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Endocrine Flashcards

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1
Q

What are the normal patterns of growth and growth velocity by age?

A
  • First year: ~25 cm/year
  • Toddler years: ~10–12 cm/year
  • Childhood: ~5–7 cm/year
  • Puberty: ~8–12 cm/year.
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2
Q

How is short stature defined and approached in pediatrics?

A
  • Height <2 SD below mean for age and sex.
  • Approach: History, examination, growth charts, labs, bone age X-ray.
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3
Q

What are the causes of proportionate short stature?

A
  • Causes:
  • Constitutional delay
  • Familial short stature
  • Chronic systemic illnesses
  • Endocrinopathies
  • Malnutrition.
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4
Q

What are the causes of disproportionate short stature?

A
  • Causes:
  • Skeletal dysplasias (e.g., achondroplasia)
  • Rickets
  • Turner syndrome
  • SHOX deficiency.
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5
Q

How should the evaluation of a child with short stature be conducted?

A
  • Evaluation:
  • Monitor growth velocity
  • Bone age
  • CBC, ESR, TSH, IGF-1/IGFBP-3
  • Karyotype (if female)
  • MRI brain (if pituitary abnormality suspected).
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6
Q

How do familial short stature, constitutional growth delay, and pathological causes differ?

A
  • Familial short stature: Normal bone age, parental height short.
  • Constitutional delay: Delayed bone age, delayed puberty.
  • Pathologic: Poor growth velocity, systemic or dysmorphic signs.
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7
Q

What are the features, diagnosis, and treatment of growth hormone deficiency in children?

A
  • Features: Short stature, delayed skeletal maturation.
  • Diagnosis: Low IGF-1, failed GH stimulation test.
  • Treatment: Daily recombinant human GH injections.
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8
Q

How does Turner syndrome present with growth failure?

A
  • Features: Short stature, webbed neck, shield chest.
  • Diagnosis: Karyotype (45,X).
  • Management: GH therapy started early.
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9
Q

What are SHOX gene mutations and their relation to short stature?

A
  • SHOX mutations cause mesomelic limb shortening.
  • Seen in Turner syndrome and isolated SHOX deficiency.
  • Leads to proportionate or disproportionate short stature.
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10
Q

What is the approach to growth hormone therapy in pediatrics?

A
  • Indications: GHD, Turner syndrome, SGA without catch-up.
  • Daily subcutaneous injections.
  • Monitor growth response and IGF-1 levels.
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11
Q

How is bone age interpreted in the evaluation of short stature?

A
  • Bone Age Interpretation:
    • Delayed bone age: Constitutional delay, GH deficiency, hypothyroidism.
    • Normal bone age: Familial short stature.
    • Advanced bone age: Precocious puberty, hyperthyroidism.
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12
Q

How should poor growth velocity be approached clinically?

A
  • Poor Growth Velocity Approach:
    • Height velocity <4 cm/year after age 3 is abnormal.
    • Evaluate systemic illnesses, nutrition, endocrine causes.
    • Repeat growth measurements every 6 months.
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13
Q

How is growth monitored in children with chronic diseases (e.g., IBD, CKD)?

A
  • Growth Monitoring in Chronic Disease:
    • Plot growth every 3–6 months.
    • Watch for growth deceleration as early marker of disease flare.
    • Adjust treatment to minimize growth suppression (e.g., steroid-sparing therapy).
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14
Q

How does celiac disease present with growth failure?

A
  • Celiac Disease and Growth Failure:
    • May present with isolated short stature without GI symptoms.
    • Screen with tissue transglutaminase IgA (TTG-IgA) and total IgA.
    • Confirm by small bowel biopsy.
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15
Q

What is psychosocial short stature (deprivation dwarfism)?

A
  • Psychosocial Short Stature (Deprivation Dwarfism):
    • Growth failure due to emotional deprivation.
    • Features: Poor growth despite adequate nutrition, bizarre eating behaviors.
    • Growth improves when child removed from adverse environment.
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16
Q

What endocrine disorders besides GH deficiency can cause short stature?

A
  • Endocrine Causes Besides GHD:
    • Hypothyroidism
    • Cushing syndrome
    • Diabetes mellitus (poorly controlled)
    • Hypopituitarism (multiple pituitary hormone deficiencies).
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17
Q

What are disorders of the IGF-1 axis, and how are they diagnosed?

A
  • Disorders of the IGF-1 Axis:
    • Primary IGF-1 deficiency (e.g., Laron syndrome).
    • Features: Severe postnatal growth failure, high GH, low IGF-1.
    • Diagnosed by IGF-1 levels and GH stimulation testing.
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18
Q

How is small for gestational age (SGA) related to growth failure?

A
  • SGA and Growth Failure:
    • ~90% catch-up by age 2 years.
    • Failure to catch up by 2–4 years suggests need for GH therapy evaluation.
    • Screen for dysmorphic syndromes if no catch-up.
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19
Q

What are examples of genetic syndromes causing short stature besides Turner syndrome?

A
  • Genetic Syndromes Causing Short Stature:
    • Noonan syndrome
    • Russell-Silver syndrome
    • Prader-Willi syndrome
    • SHOX gene haploinsufficiency without Turner syndrome.
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20
Q

What red flags suggest an urgent need for endocrinology referral in a child with short stature?

A
  • Red Flags for Endocrine Referral:
    • Height <–3 SD for age
    • Poor growth velocity (<4 cm/year)
    • Dysmorphic features
    • Severe delayed bone age
    • Signs of systemic or endocrine disease (e.g., hypothyroidism).
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21
Q

What is catch-up growth after chronic illness, and how is it monitored?

A
  • Catch-up Growth:
    • Accelerated growth after resolution of chronic illness (e.g., malnutrition, IBD, CKD).
    • Requires regular monitoring every 3–6 months.
    • Failure to catch up suggests persistent underlying disease or endocrine dysfunction.
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22
Q

How does hypothyroidism affect growth and bone maturation in children?

A
  • Hypothyroidism Effects:
    • Severe growth failure with delayed bone age.
    • Weight gain despite poor linear growth.
    • Bone age typically much less than chronological age.
    • Prompt treatment with levothyroxine improves growth.
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23
Q

How does Cushing syndrome impact linear growth in pediatrics?

A
  • Cushing Syndrome Effects:
    • Impaired linear growth despite weight gain.
    • Central obesity, round facies, thin skin, easy bruising.
    • Suppressed GH secretion secondary to hypercortisolism.
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24
Q

How does poorly controlled Type 1 diabetes mellitus affect growth?

A
  • Impact of Poorly Controlled Type 1 DM:
    • Growth deceleration due to catabolic state.
    • Pubertal delay if longstanding poor glycemic control.
    • Importance of maintaining good glycemic control to preserve growth potential.
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25
How is idiopathic short stature differentiated from pathologic causes?
- **Idiopathic Short Stature:** - Short stature with no identifiable cause after thorough evaluation. - Normal growth velocity. - Normal labs and bone age. - No systemic illness or endocrinopathy.
26
What are key differences between constitutional delay and growth hormone deficiency?
- **Constitutional Delay vs GH Deficiency:** - **Constitutional Delay:** Normal response to GH stimulation, delayed bone age, delayed puberty. - **GH Deficiency:** Abnormal GH stimulation test, low IGF-1, poor growth velocity even with normal puberty onset.
27
What roles do nutrition and psychosocial environment play in pediatric growth?
- **Nutrition and Psychosocial Factors:** - Malnutrition is a common reversible cause of growth failure. - Emotional deprivation (psychosocial dwarfism) leads to poor growth despite normal caloric intake. - Improvement occurs with nutritional rehabilitation or environmental change.
28
How is adult height predicted, and what are its limitations?
- **Adult Height Prediction:** - Methods: Mid-parental height formula, bone age estimation. - Limitations: Cannot account for chronic disease, puberty timing, or psychosocial factors precisely.
29
Which genetic syndromes besides Turner are associated with short stature?
- **Genetic Syndromes with Short Stature:** - Prader-Willi syndrome: Hypotonia, obesity, growth failure. - Noonan syndrome: Webbed neck, congenital heart defects. - Russell-Silver syndrome: IUGR, triangular face, body asymmetry.
30
Why is early diagnosis and treatment important in pediatric growth disorders?
- **Importance of Early Diagnosis:** - Early intervention can optimize final adult height. - Early treatment of underlying causes (e.g., hypothyroidism, celiac disease) prevents permanent growth failure. - Psychological impact minimized by timely management.
31
What is the difference between gigantism and acromegaly in pediatrics?
- **Gigantism vs Acromegaly:** - **Gigantism:** GH excess **before** epiphyseal closure → excessive linear growth. - **Acromegaly:** GH excess **after** epiphyseal closure → soft tissue and bone thickening. - Gigantism presents in childhood/adolescence with very tall stature.
32
What are SHOX gene duplications and how do they affect growth?
- **SHOX Gene Duplications:** - Extra SHOX gene copies can lead to tall stature. - Opposite of SHOX deletions (short stature). - May present with long limbs and mild skeletal disproportion.
33
What are the growth characteristics of Silver-Russell syndrome?
- **Silver-Russell Syndrome:** - Features: Intrauterine growth retardation (IUGR), triangular facies, body asymmetry, feeding difficulties. - Poor catch-up growth postnatally. - Diagnosis: Genetic imprinting defects (chromosome 11p15, maternal uniparental disomy of chromosome 7).
34
What is Seckel syndrome, and how does it present?
- **Seckel Syndrome:** - Also called 'bird-headed dwarfism'. - Features: Severe prenatal and postnatal growth retardation, microcephaly, intellectual disability. - Genetic disorder (autosomal recessive).
35
How do mucopolysaccharidoses (MPS) lead to growth failure?
- **Mucopolysaccharidoses (MPS) and Growth Failure:** - Lysosomal storage disorders. - Features: Short stature, joint stiffness, dysostosis multiplex. - Example syndromes: Hurler, Hunter. - Diagnosed by enzyme assays and urine GAGs.
36
How does chronic anemia (e.g., thalassemia) affect growth in children?
- **Chronic Anemia (e.g., Thalassemia) and Growth:** - Hypoxia and chronic disease state impair growth. - Iron overload (from transfusions) can cause endocrine dysfunction (e.g., GH deficiency, hypothyroidism).
37
What mechanisms cause growth failure in chronic renal disease?
- **Mechanisms of Growth Failure in CKD:** - Poor nutrition. - Metabolic acidosis. - Anemia. - GH resistance. - Bone mineral disease. - Recombinant GH therapy may improve growth if metabolic control optimized.
38
How does glucocorticoid excess (exogenous vs endogenous) impair growth?
- **Glucocorticoid Excess and Growth:** - Exogenous steroids (e.g., for asthma, IBD) and endogenous Cushing syndrome suppress GH axis. - Directly inhibit growth plate chondrocyte proliferation. - Result: Linear growth retardation with truncal obesity.
39
How does congenital heart disease affect linear growth?
- **Congenital Heart Disease and Growth:** - Poor systemic oxygenation. - Increased caloric expenditure due to cardiac workload. - Feeding difficulties. - Associated with poor linear growth and failure to thrive (FTT).
40
What is the recommended long-term follow-up for children receiving GH therapy?
- **GH Therapy Long-Term Follow-Up:** - Monitor height velocity and IGF-1 levels every 3–6 months. - Screen for scoliosis, glucose intolerance, intracranial hypertension. - Adjust GH dose based on weight and response. - Continue therapy until near-final height achieved.
41
What is the growth pattern in children born small for gestational age (SGA) without catch-up growth?
- **SGA Without Catch-Up Growth:** - ~10% of SGA infants fail to achieve catch-up growth by 2–4 years. - Often remain short without intervention. - GH therapy can be considered if height <–2.5 SD and poor growth velocity.
42
What is Bloom syndrome and how does it affect growth?
- **Bloom Syndrome:** - Autosomal recessive disorder. - Features: Short stature, photosensitivity, immunodeficiency, cancer predisposition. - Caused by mutations in BLM gene (DNA helicase).
43
What is Rothmund-Thomson syndrome and its effect on stature?
- **Rothmund-Thomson Syndrome:** - Rare genetic disorder. - Features: Short stature, poikiloderma (skin changes), skeletal abnormalities, cataracts. - Associated with RECQL4 gene mutations.
44
How does chronic gastrointestinal disease (e.g., Crohn's, celiac) affect growth?
- **Impact of GI Disease on Growth:** - Chronic inflammation, nutrient malabsorption, increased energy expenditure. - Growth failure often precedes GI symptoms. - Important to monitor height and weight serially.
45
What is the role of growth hormone (GH) therapy in idiopathic short stature (ISS)?
- **GH Therapy in Idiopathic Short Stature (ISS):** - Approved use (controversial). - Modest increase in adult height (~5–7 cm on average). - Requires careful patient selection and counseling.
46
What is constitutional tall stature, and how is it diagnosed?
- **Constitutional Tall Stature:** - Tall stature consistent with family patterns. - Normal bone age advancement. - No signs of systemic or endocrine disease. - Normal physical exam.
47
How does hyperthyroidism affect skeletal maturation and growth?
- **Hyperthyroidism and Skeletal Maturation:** - Accelerates bone age. - Can lead to premature epiphyseal closure. - May reduce final adult height despite initial tall stature.
48
What are precocious puberty variants (isolated thelarche, isolated pubarche) and their impact on growth?
- **Precocious Puberty Variants:** - **Isolated Thelarche:** Benign premature breast development without other pubertal signs. - **Isolated Pubarche:** Early pubic hair due to adrenal maturation (adrenarche). - Typically no significant impact on final height.
49
How can pathologic vs benign tall stature be differentiated?
- **Differentiating Benign vs Pathologic Tall Stature:** - Benign: Normal proportions, consistent family history, normal physical exam. - Pathologic: Dysmorphic features, rapid growth velocity, systemic symptoms (e.g., Marfan, endocrine tumors).
50
What are the ethical considerations in using GH therapy for non-GH-deficient children?
- **Ethical Considerations in GH Therapy:** - Cost vs benefit (modest height gain). - Medicalization of normal variants. - Informed consent must address realistic expectations and potential side effects.
51
What is the normal timing and sequence of pubertal development in boys and girls?
- **Normal Pubertal Timing:** - **Girls:** - Breast development (thelarche) ~10 years. - Menarche ~12.5 years (2–2.5 years after thelarche). - **Boys:** - Testicular enlargement (≥4 mL) ~11–12 years. - Followed by penile growth, pubic hair, height spurt.
52
What is precocious puberty, and how is it classified?
- **Precocious Puberty:** - Development of secondary sexual characteristics before: - Age 8 in girls. - Age 9 in boys. - **Classifications:** - Central (gonadotropin-dependent) - Peripheral (gonadotropin-independent).
53
What are common causes of central precocious puberty (CPP)?
- **Causes of Central Precocious Puberty (CPP):** - Idiopathic (most common in girls) - CNS tumors (hypothalamic hamartoma, astrocytoma) - CNS infections (meningitis, encephalitis) - Cranial irradiation or trauma.
54
What are common causes of peripheral precocious puberty (PPP)?
- **Causes of Peripheral Precocious Puberty (PPP):** - McCune-Albright syndrome - Congenital adrenal hyperplasia (CAH) - Ovarian or testicular tumors - Exogenous sex steroids.
55
How is a child with suspected early pubertal signs evaluated?
- **Evaluation of Early Pubertal Signs:** - Detailed history (timing, progression). - Physical examination (Tanner staging). - Bone age X-ray (advanced in true puberty). - Basal and stimulated LH/FSH. - Pelvic ultrasound in girls; brain MRI if central causes suspected.
56
What is the management of central precocious puberty?
- **Management of Central Precocious Puberty:** - GnRH agonist therapy (e.g., leuprolide) to suppress LH/FSH pulsatility. - Goal: Halt sexual maturation and preserve adult height potential.
57
What is the definition of delayed puberty in boys and girls?
- **Definition of Delayed Puberty:** - **Girls:** No breast development by age 13. - **Boys:** No testicular enlargement by age 14. - Also consider slow progression if puberty initiated but stalled.
58
What are the common causes of delayed puberty?
- **Common Causes of Delayed Puberty:** - Constitutional delay of growth and puberty (CDGP) (most common) - Hypogonadotropic hypogonadism (e.g., Kallmann syndrome) - Hypergonadotropic hypogonadism (e.g., Turner syndrome, Klinefelter syndrome).
59
How is the diagnostic workup for delayed puberty approached?
- **Diagnostic Workup for Delayed Puberty:** - Growth chart review. - Bone age X-ray. - LH, FSH, estradiol/testosterone levels. - Karyotype (girls: Turner; boys: Klinefelter if hypergonadotropic). - MRI brain if hypogonadotropic hypogonadism suspected.
60
How is delayed puberty managed based on etiology?
- **Management of Delayed Puberty:** - **CDGP:** Reassurance or low-dose sex steroid therapy. - **Hypogonadotropic hypogonadism:** Hormone replacement therapy. - **Hypergonadotropic hypogonadism:** Estrogen/testosterone replacement and monitoring.
61
What are the distinguishing features between central and peripheral precocious puberty on hormonal testing?
- **Central vs Peripheral Precocious Puberty on Hormonal Testing:** - **Central:** Elevated LH at baseline or after GnRH stimulation. - **Peripheral:** Low LH and FSH; high sex steroid levels independent of gonadotropins.
62
What are key clinical features of McCune-Albright syndrome?
- **Key Features of McCune-Albright Syndrome:** - Triad: Peripheral precocious puberty, café-au-lait macules, fibrous dysplasia of bone. - Caused by activating mutation in GNAS gene. - Precocious puberty often irregular and autonomous.
63
How does congenital adrenal hyperplasia (CAH) cause peripheral precocious puberty?
- **CAH and Peripheral Precocious Puberty:** - 21-hydroxylase deficiency → excess adrenal androgens. - Features: Premature pubarche, rapid growth, advanced bone age. - Salt-wasting crisis possible in classic form.
64
What is the role of brain MRI in the workup of precocious puberty?
- **Role of Brain MRI in Precocious Puberty:** - Indicated in all boys with CPP. - Indicated in girls <6 years with CPP or abnormal neurologic signs. - To evaluate for CNS lesions (hypothalamic hamartoma, tumors).
65
When should treatment be initiated for central precocious puberty?
- **When to Initiate Treatment for CPP:** - Rapid pubertal progression. - Advanced bone age threatening adult height. - Significant psychological distress. - Generally, treatment is indicated if onset <6 years or very rapid progression after 6 years.
66
What are causes of hypogonadotropic hypogonadism leading to delayed puberty?
- **Causes of Hypogonadotropic Hypogonadism:** - Kallmann syndrome - Chronic systemic disease (e.g., malnutrition, IBD) - Functional causes (stress, excessive exercise) - CNS tumors (craniopharyngioma, pituitary adenomas).
67
What are causes of hypergonadotropic hypogonadism leading to delayed puberty?
- **Causes of Hypergonadotropic Hypogonadism:** - Gonadal dysgenesis (Turner syndrome, Klinefelter syndrome) - Premature ovarian failure - Radiation or chemotherapy-induced gonadal damage.
68
How does Kallmann syndrome present in delayed puberty?
- **Kallmann Syndrome Presentation:** - Delayed or absent puberty. - Anosmia or hyposmia (loss or reduction of smell). - Hypogonadotropic hypogonadism with low LH/FSH and sex steroids.
69
What is the importance of bone age in evaluating disorders of puberty?
- **Importance of Bone Age:** - Advanced in precocious puberty. - Delayed in constitutional delay. - Helps distinguish timing and progression of pubertal disorders.
70
How should constitutional delay of growth and puberty (CDGP) be managed?
- **Management of CDGP:** - Reassurance for mild cases. - Short course of low-dose sex steroids if psychological distress or extreme delay. - Careful monitoring for spontaneous pubertal progression.
71
What are normal variants of puberty, and how are they differentiated from true precocious puberty?
- **Normal Variants of Puberty:** - **Premature adrenarche:** Early pubic/axillary hair without other pubertal changes. - **Premature thelarche:** Isolated breast development. - No rapid progression, no bone age advancement, no pubertal LH rise.
72
What clinical features suggest pathologic puberty rather than normal variation?
- **Red Flags for Pathologic Puberty:** - Very rapid progression. - Neurologic signs (e.g., headache, visual changes). - Severe bone age advancement. - Signs of virilization (deepening voice, clitoromegaly). - Growth deceleration (suggests systemic disease).
73
What is the role of GnRH stimulation testing in evaluating puberty disorders?
- **GnRH Stimulation Testing:** - Distinguishes central vs peripheral puberty. - **Central:** Pubertal LH rise (>5–8 IU/L after GnRH). - **Peripheral:** No significant LH response; high sex steroids.
74
How do ovarian cysts lead to early puberty in girls?
- **Ovarian Cysts and Early Puberty:** - Estrogen secretion from functional ovarian cysts. - May cause isolated breast development or vaginal bleeding. - Usually transient and self-resolving.
75
What is testotoxicosis (familial male-limited precocious puberty)?
- **Testotoxicosis:** - Activating mutation of LH receptor. - Gonadotropin-independent testosterone production. - Early virilization without elevated LH/FSH. - Treated with androgen blockade (e.g., bicalutamide) + aromatase inhibitors.
76
How does hypothyroidism impact pubertal timing?
- **Hypothyroidism and Puberty:** - Severe hypothyroidism may paradoxically cause precocious puberty (Van Wyk-Grumbach syndrome). - Features: Breast development, galactorrhea, delayed bone age. - Mechanism: TSH cross-reactivity with FSH receptors.
77
What is the approach to gynecomastia in adolescent boys?
- **Approach to Gynecomastia in Boys:** - Assess timing, size, and tenderness. - Review medications, drug use (anabolic steroids, marijuana). - Evaluate for underlying endocrinopathies if atypical.
78
How can physiologic pubertal gynecomastia be differentiated from pathologic causes?
- **Physiologic vs Pathologic Gynecomastia:** - **Physiologic:** - Bilateral, symmetric. - Appears around Tanner stage 2–3. - Resolves within 1–2 years. - **Pathologic:** - Unilateral, rapid growth, systemic signs (e.g., testicular mass, liver disease).
79
What genetic conditions can cause delayed puberty?
- **Genetic Causes of Delayed Puberty:** - Kallmann syndrome (anosmia + hypogonadotropic hypogonadism) - Turner syndrome (45,X) - Klinefelter syndrome (47,XXY) - Mutations in genes regulating GnRH neuron migration.
80
What is the psychological impact of disorders of puberty on affected children?
- **Psychological Impact:** - Early puberty: Low self-esteem, peer problems, risk-taking behaviors. - Delayed puberty: Anxiety, depression, bullying. - Importance of psychological support and counseling.
81
How does obesity affect the timing of puberty in children?
- **Obesity and Puberty:** - In girls: Associated with earlier onset of puberty (thelarche, menarche). - In boys: May delay puberty onset. - Mechanism: Increased peripheral aromatization of androgens to estrogens.
82
What is the role of leptin and nutrition in puberty onset?
- **Role of Leptin and Nutrition:** - Leptin produced by adipose tissue is essential for puberty initiation. - Severe malnutrition or low body fat can delay or suppress puberty. - Adequate nutritional status signals hypothalamic-pituitary-gonadal (HPG) axis activation.
83
How can chronic illness impact pubertal development?
- **Impact of Chronic Illness:** - Chronic diseases (e.g., IBD, CF, CKD) can delay puberty. - Mechanisms: Inflammation, poor nutrition, chronic stress on HPG axis. - Growth failure often accompanies pubertal delay.
84
What is aromatase excess syndrome, and how does it cause early puberty?
- **Aromatase Excess Syndrome:** - Increased conversion of androgens to estrogens. - Features: Gynecomastia in boys, early thelarche/menarche in girls. - Caused by duplications involving the CYP19A1 gene.
85
Which ovarian tumors are associated with precocious puberty in girls?
- **Ovarian Tumors Associated with Precocious Puberty:** - Granulosa cell tumors - Theca cell tumors - Produce excess estrogen → early breast development and bleeding.
86
Which testicular tumors are associated with precocious puberty in boys?
- **Testicular Tumors Associated with Precocious Puberty:** - Leydig cell tumors (secrete testosterone). - Germ cell tumors producing hCG (mimics LH stimulation of Leydig cells).
87
How can constitutional delay of growth and puberty be distinguished from permanent hypogonadism?
- **Constitutional Delay vs Permanent Hypogonadism:** - Constitutional: Delayed bone age, spontaneous puberty expected. - Permanent hypogonadism: Persistently low sex steroids, elevated gonadotropins (in hypergonadotropic forms).
88
What is the role of sex steroid priming in the evaluation of delayed puberty?
- **Sex Steroid Priming:** - Short course of low-dose estrogen (girls) or testosterone (boys) before dynamic pituitary testing. - Improves diagnostic accuracy by sensitizing the HPG axis.
89
What is the role of inhibin B and anti-Müllerian hormone (AMH) in assessing pubertal status?
- **Inhibin B and AMH:** - Markers of gonadal function. - Low inhibin B and AMH suggest impaired gonadal function. - Useful adjuncts when gonadotropin levels are equivocal.
90
How should families be counseled about pubertal disorders?
- **Family Counseling:** - Provide reassurance about common normal variants. - Emphasize the importance of monitoring growth and development. - Discuss treatment options clearly if intervention needed. - Address psychological and social impacts of pubertal disorders.
91
What are the basic components of normal thyroid physiology?
- **Normal Thyroid Physiology:** - Hypothalamus releases TRH → stimulates pituitary to secrete TSH → stimulates thyroid gland. - Thyroid produces thyroxine (T4) and triiodothyronine (T3). - T4 converted to T3 in peripheral tissues. - Negative feedback regulates TRH and TSH secretion.
92
What are the causes of congenital hypothyroidism?
- **Causes of Congenital Hypothyroidism:** - Thyroid dysgenesis (aplasia, ectopia, hypoplasia) (~85%). - Dyshormonogenesis (defects in hormone synthesis). - Maternal iodine deficiency. - Maternal TSH receptor-blocking antibodies. - Inborn errors of thyroid hormone transport/metabolism.
93
What are the clinical features of congenital hypothyroidism?
- **Clinical Features of Congenital Hypothyroidism:** - Often asymptomatic at birth (due to maternal T4). - Prolonged jaundice. - Poor feeding, constipation. - Hypotonia, macroglossia. - Large anterior fontanelle. - Umbilical hernia.
94
How is congenital hypothyroidism diagnosed and managed?
- **Diagnosis and Management of Congenital Hypothyroidism:** - Diagnosed by newborn screening (elevated TSH, low T4). - Confirmatory venous TSH and free T4. - Immediate initiation of levothyroxine therapy. - Target: Normalize T4 quickly (within 2 weeks) to avoid intellectual disability.
95
What are the common causes of acquired hypothyroidism in children?
- **Common Causes of Acquired Hypothyroidism:** - Hashimoto thyroiditis (autoimmune thyroiditis) (most common). - Post-surgical hypothyroidism. - Radiation-induced. - Thyroid hormone resistance (rare).
96
What are the clinical features and diagnosis of Hashimoto thyroiditis?
- **Clinical Features and Diagnosis of Hashimoto Thyroiditis:** - Features: Goiter, growth deceleration, fatigue, constipation, cold intolerance. - Labs: Elevated TSH, low free T4, positive anti-thyroid peroxidase (TPO) antibodies. - Ultrasound: Heterogeneous thyroid texture.
97
What are the causes of hyperthyroidism in children?
- **Causes of Hyperthyroidism in Children:** - Graves disease (most common). - Toxic multinodular goiter. - Toxic adenoma. - Thyroiditis (transient hyperthyroid phase).
98
What are the clinical features and complications of pediatric Graves disease?
- **Clinical Features and Complications of Pediatric Graves Disease:** - Symptoms: Weight loss, heat intolerance, palpitations, anxiety, tremors. - Signs: Goiter, tachycardia, hypertension, ophthalmopathy (exophthalmos). - Complications: Growth acceleration, bone age advancement, cardiac arrhythmias.
99
How is hyperthyroidism diagnosed in children?
- **Diagnosis of Hyperthyroidism:** - Low TSH, elevated free T4 and/or T3. - Positive TSH receptor antibodies (TRAb) in Graves disease. - Thyroid ultrasound and uptake scan if diagnosis unclear.
100
What are the management options for pediatric hyperthyroidism?
- **Management Options for Pediatric Hyperthyroidism:** - **Medical:** Methimazole (first-line). - **Beta-blockers:** For symptom control. - **Definitive:** Radioactive iodine ablation (RAI) or total thyroidectomy in selected cases. - Regular monitoring for treatment response and side effects.
101
What are the side effects and monitoring considerations for methimazole therapy in children?
- **Methimazole Side Effects:** - Minor: Rash, arthralgia, GI upset. - Major (rare): Agranulocytosis, hepatotoxicity, vasculitis. - **Monitoring:** CBC and liver function tests if symptoms suggestive. - Parents must be advised to seek urgent care for sore throat or fever.
102
When is radioactive iodine (RAI) therapy preferred for pediatric Graves disease?
- **Radioactive Iodine Therapy in Children:** - Preferred in children >10 years or those with poor response/intolerance to antithyroid drugs. - Contraindicated in young children (<5 years) and severe ophthalmopathy. - Induces hypothyroidism, requiring lifelong levothyroxine.
103
What are the indications for thyroidectomy in children with hyperthyroidism?
- **Indications for Thyroidectomy:** - Large goiter causing compressive symptoms. - Suspicion of malignancy. - Severe ophthalmopathy. - Poor compliance with medical therapy. - Experienced pediatric thyroid surgeon required to minimize complications (e.g., hypoparathyroidism, vocal cord paralysis).
104
What is subclinical hypothyroidism, and how is it managed in pediatrics?
- **Subclinical Hypothyroidism:** - Elevated TSH with normal free T4. - Often mild and asymptomatic. - Management: Monitor vs treat depending on TSH level (>10 mIU/L usually treated) and clinical context.
105
What are the features of thyroiditis in children, and how is it classified?
- **Thyroiditis Classification:** - **Hashimoto thyroiditis:** Chronic lymphocytic. - **Subacute (de Quervain) thyroiditis:** Painful, viral/post-viral. - **Painless (silent) thyroiditis:** Autoimmune, transient. - **Suppurative (infectious) thyroiditis:** Bacterial infection.
106
How does painless (silent) thyroiditis present, and what is its natural history?
- **Painless (Silent) Thyroiditis:** - Presents with transient hyperthyroidism followed by hypothyroidism. - Self-limited course (3–6 months). - Positive anti-TPO antibodies often present. - Supportive management unless severe symptoms.
107
What is suppurative (infectious) thyroiditis, and how does it present in children?
- **Suppurative Thyroiditis:** - Acute onset neck pain, fever, dysphagia. - Tender thyroid gland. - Common organisms: Staphylococcus aureus, Streptococcus spp. - Management: IV antibiotics, surgical drainage if abscess forms.
108
What is thyroid hormone resistance syndrome, and how does it present?
- **Thyroid Hormone Resistance Syndrome:** - Mutation in thyroid hormone receptor beta (TRβ). - Features: Elevated free T4/T3 with non-suppressed TSH. - Variable clinical presentation: Goiter, hyperactivity, tachycardia without classic hyperthyroid symptoms.
109
What is the role of thyroid ultrasound in pediatric thyroid disorders?
- **Role of Thyroid Ultrasound:** - Evaluate goiter size and characteristics. - Differentiate solid vs cystic nodules. - Guide fine-needle aspiration (FNA) for suspicious nodules. - Monitor known thyroid nodules over time.
110
When should thyroid nodules in children be evaluated by fine-needle aspiration (FNA)?
- **When to Perform FNA on Thyroid Nodules:** - Nodules >1 cm with suspicious ultrasound features (microcalcifications, irregular margins, hypoechogenicity). - Rapidly growing nodules. - Suspicion based on clinical or family history (e.g., MEN syndromes).
111
What are the differences between Graves ophthalmopathy and other causes of eye symptoms in children?
- **Graves Ophthalmopathy vs Other Causes:** - Graves: Bilateral proptosis, lid lag, periorbital edema. - Different from infections (cellulitis) or tumors (unilateral, painful). - Graves ophthalmopathy can occur independently of thyroid function control.
112
How does neonatal thyrotoxicosis occur, and what are its clinical features?
- **Neonatal Thyrotoxicosis:** - Caused by maternal TSH receptor-stimulating antibodies crossing placenta. - Symptoms: Irritability, tachycardia, poor feeding, failure to thrive, goiter, exophthalmos. - Seen in babies of mothers with Graves disease.
113
How is neonatal thyrotoxicosis diagnosed and managed?
- **Diagnosis and Management of Neonatal Thyrotoxicosis:** - Diagnosis: Low TSH, elevated free T4/T3, positive TSH receptor antibodies. - Management: Beta-blockers (propranolol), methimazole. - Usually self-limited (maternal antibodies clear over weeks to months).
114
What is ectopic thyroid tissue, and how does it present in pediatrics?
- **Ectopic Thyroid Tissue:** - Thyroid tissue located outside the normal anatomic position (e.g., lingual thyroid). - Presents as midline mass; may cause hypothyroidism. - Confirmed by radionuclide scan. - May require thyroid hormone replacement.
115
What is thyroglossal duct cyst, and what is its relation to thyroid pathology?
- **Thyroglossal Duct Cyst:** - Midline neck mass, moves with swallowing or tongue protrusion. - Results from incomplete involution of the thyroglossal duct. - Surgical removal (Sistrunk procedure) to prevent infection/recurrence.
116
How is hypothyroidism due to iodine deficiency diagnosed and managed?
- **Iodine Deficiency Hypothyroidism:** - Common in regions with low dietary iodine. - Features: Goiter, hypothyroidism. - Diagnosed clinically and via urinary iodine levels. - Managed with iodine supplementation and/or levothyroxine if needed.
117
What is transient congenital hypothyroidism, and how is it differentiated from permanent cases?
- **Transient Congenital Hypothyroidism:** - Temporary hypothyroidism due to maternal antibodies, iodine exposure, or immaturity. - Retest thyroid function at age 3 years after stopping therapy. - Permanent CH requires lifelong levothyroxine.
118
What is the importance of early treatment initiation in congenital hypothyroidism?
- **Importance of Early Treatment in Congenital Hypothyroidism:** - Initiate therapy ideally before 2 weeks of age. - Prevents intellectual disability and promotes normal neurodevelopment. - Close monitoring during infancy for dose adjustment.
119
What are the risk factors for thyroid carcinoma in children?
- **Risk Factors for Pediatric Thyroid Cancer:** - History of radiation exposure. - Family history of thyroid cancer. - Genetic syndromes (e.g., MEN 2, Cowden syndrome). - Suspicious nodule characteristics (solid, hypoechoic, microcalcifications).
120
What is the prognosis of pediatric thyroid cancer compared to adults?
- **Prognosis of Pediatric Thyroid Cancer:** - Generally excellent prognosis despite frequent lymph node metastasis. - Higher recurrence rate than adults but low mortality. - Long-term follow-up necessary.
121
What familial syndromes are associated with pediatric thyroid cancer?
- **Familial Syndromes and Thyroid Cancer:** - MEN 2A and 2B (medullary thyroid carcinoma). - Familial medullary thyroid carcinoma (FMTC). - PTEN hamartoma syndrome (Cowden syndrome). - DICER1 syndrome (thyroid neoplasia).
122
What are the differences between papillary and follicular thyroid carcinoma in children?
- **Papillary vs Follicular Thyroid Carcinoma:** - **Papillary:** Most common; lymphatic spread; excellent prognosis. - **Follicular:** Less common; hematogenous spread (lungs, bones); slightly worse prognosis. - Both require long-term surveillance.
123
How is thyroid function commonly affected in Down syndrome?
- **Thyroid Function in Down Syndrome:** - Increased risk of hypothyroidism (both congenital and acquired). - Often associated with Hashimoto thyroiditis. - Routine thyroid function screening recommended.
124
What is sick euthyroid syndrome (non-thyroidal illness syndrome)?
- **Sick Euthyroid Syndrome:** - Abnormal thyroid labs in critically ill patients without intrinsic thyroid disease. - Typically low T3, normal/low T4, normal/low TSH. - No treatment needed; resolves with recovery from illness.
125
How does amiodarone cause thyroid dysfunction in children?
- **Amiodarone-Induced Thyroid Dysfunction:** - Hypothyroidism: Inhibition of T4 to T3 conversion, high iodine load. - Hyperthyroidism: Inflammatory destruction of thyroid tissue. - Requires regular monitoring of thyroid function tests.
126
What are the effects of lithium on thyroid function?
- **Effects of Lithium on Thyroid:** - Inhibits thyroid hormone release. - Increases risk of hypothyroidism and goiter. - Routine monitoring required in children on chronic lithium therapy.
127
How does radiation exposure increase the risk of thyroid disease in pediatrics?
- **Radiation and Thyroid Risk:** - Increases risk of thyroid nodules, hypothyroidism, and thyroid carcinoma. - Particularly high risk if exposed at young age. - Long-term surveillance with thyroid exams and ultrasound if indicated.
128
What is the role of calcitonin in pediatric thyroid pathology?
- **Calcitonin Role in Pediatric Thyroid Disease:** - Produced by thyroid C-cells. - Marker for medullary thyroid carcinoma. - Measured in high-risk familial cases (e.g., MEN 2).
129
What is MCT8 deficiency, and how does it affect thyroid hormone transport?
- **MCT8 Deficiency:** - Defect in monocarboxylate transporter 8 (MCT8), a thyroid hormone transporter. - Severe neurodevelopmental delay + abnormal thyroid labs (high T3, low T4, normal/slightly elevated TSH).
130
How should thyroid nodules in children with a history of malignancy be evaluated?
- **Thyroid Nodules After Prior Malignancy:** - Higher risk of malignancy. - Require prompt evaluation with ultrasound and FNA. - History of radiation therapy increases risk further.
131
What are the key hormones regulating calcium homeostasis?
- **Calcium Regulation Hormones:** - **Parathyroid hormone (PTH):** Increases serum calcium by bone resorption, renal reabsorption, and activating vitamin D. - **Vitamin D:** Increases intestinal calcium and phosphate absorption. - **Calcitonin:** Lowers serum calcium by inhibiting bone resorption (minor role).
132
What are the causes of hypocalcemia in neonates?
- **Causes of Hypocalcemia in Neonates:** - Early onset (<72h): Prematurity, birth asphyxia, maternal diabetes, sepsis. - Late onset (>72h): Hypoparathyroidism, DiGeorge syndrome, high phosphate intake (e.g., cow’s milk).
133
What are the causes of hypocalcemia in older children?
- **Causes of Hypocalcemia in Older Children:** - Hypoparathyroidism (autoimmune, postsurgical). - Vitamin D deficiency or resistance. - Chronic kidney disease (secondary hyperparathyroidism). - Pseudohypoparathyroidism (PTH resistance).
134
What are the clinical features of hypocalcemia in children?
- **Clinical Features of Hypocalcemia:** - Neuromuscular irritability: Tetany, carpopedal spasm, laryngospasm. - Seizures. - Chvostek and Trousseau signs. - QT prolongation on ECG.
135
How is acute symptomatic hypocalcemia managed?
- **Management of Acute Symptomatic Hypocalcemia:** - IV calcium gluconate (slow infusion; monitor cardiac rhythm). - Oral calcium supplementation after stabilization. - Correct underlying cause (e.g., magnesium deficiency).
136
What are the causes of hypercalcemia in pediatrics?
- **Causes of Hypercalcemia in Pediatrics:** - Hyperparathyroidism (rare in children). - Malignancy (leukemia, lymphoma). - Vitamin D intoxication. - Granulomatous diseases (sarcoidosis, TB). - Williams syndrome.
137
What are the clinical features and complications of hypercalcemia?
- **Clinical Features and Complications of Hypercalcemia:** - Polyuria, polydipsia, dehydration. - Abdominal pain, vomiting, constipation. - Muscle weakness, confusion. - Nephrocalcinosis, kidney stones.
138
How is severe hypercalcemia managed in children?
- **Management of Severe Hypercalcemia:** - Aggressive IV hydration with normal saline. - Loop diuretics (after hydration). - Bisphosphonates (e.g., pamidronate) in refractory cases. - Treat underlying cause.
139
What are the types and pathophysiology of rickets?
- **Types and Pathophysiology of Rickets:** - Nutritional rickets: Vitamin D deficiency → decreased calcium/phosphate absorption. - Genetic rickets: Disorders of vitamin D metabolism or phosphate handling (e.g., X-linked hypophosphatemia).
140
What are the clinical features and diagnosis of nutritional rickets?
- **Clinical Features and Diagnosis of Nutritional Rickets:** - Features: Delayed closure of fontanelles, craniotabes, bowed legs, wrist widening. - Labs: Low 25(OH) vitamin D, low-normal calcium, low phosphate, elevated alkaline phosphatase, elevated PTH. - X-rays: Metaphyseal cupping, fraying, widening.
141
What are the biochemical findings in nutritional rickets?
- **Biochemical Findings in Nutritional Rickets:** - Low 25(OH) vitamin D. - Low to normal serum calcium. - Low serum phosphate. - Elevated alkaline phosphatase. - Elevated PTH (secondary hyperparathyroidism).
142
What is hypophosphatemic rickets, and how does it differ from nutritional rickets?
- **Hypophosphatemic vs Nutritional Rickets:** - **Hypophosphatemic:** Normal calcium, low phosphate, normal vitamin D. - **Nutritional:** Low vitamin D, low-normal calcium, low phosphate. - Hypophosphatemic rickets is often genetic and resistant to vitamin D.
143
How is X-linked hypophosphatemic rickets diagnosed and managed?
- **X-linked Hypophosphatemic Rickets:** - Mutation in PHEX gene → impaired phosphate reabsorption. - Labs: Low serum phosphate, normal calcium, elevated FGF23. - Management: Phosphate supplements + active vitamin D (calcitriol).
144
What are the clinical features of vitamin D–dependent rickets type 1 and type 2?
- **Vitamin D–Dependent Rickets:** - **Type 1:** Deficiency of 1α-hydroxylase enzyme (cannot activate vitamin D). - **Type 2:** End-organ resistance to vitamin D. - Both present with severe rickets, hypocalcemia, hypophosphatemia, and elevated PTH.
145
What is the pathophysiology of pseudohypoparathyroidism?
- **Pseudohypoparathyroidism Pathophysiology:** - End-organ resistance to PTH. - Labs: Hypocalcemia, hyperphosphatemia, elevated PTH. - Caused by mutations affecting Gsα protein signaling.
146
What are the features of Albright hereditary osteodystrophy?
- **Features of Albright Hereditary Osteodystrophy (AHO):** - Short stature. - Obesity. - Brachydactyly (shortened 4th/5th metacarpals). - Developmental delay. - Associated with pseudohypoparathyroidism type 1a.
147
What is primary hyperparathyroidism in pediatrics, and how does it present?
- **Primary Hyperparathyroidism in Pediatrics:** - Rare; most often due to parathyroid adenoma. - Features: Hypercalcemia symptoms (polyuria, dehydration, bone pain, fractures). - Labs: Elevated calcium, elevated PTH, low phosphate.
148
How does secondary hyperparathyroidism differ from tertiary hyperparathyroidism?
- **Secondary vs Tertiary Hyperparathyroidism:** - **Secondary:** Compensatory PTH elevation in response to hypocalcemia (e.g., CKD). - **Tertiary:** Autonomous PTH secretion after long-standing secondary hyperparathyroidism (e.g., post-transplant).
149
What are causes of secondary hyperparathyroidism in children?
- **Causes of Secondary Hyperparathyroidism in Children:** - Chronic kidney disease (most common). - Vitamin D deficiency. - Malabsorption syndromes (e.g., celiac disease, cystic fibrosis).
150
What are key radiographic features of rickets?
- **Radiographic Features of Rickets:** - Widened, cupped, and frayed metaphyses. - Bowing of long bones. - Delayed bone age. - Generalized osteopenia.
151
What are the causes and features of osteogenesis imperfecta (OI) in children?
- **Causes and Features of Osteogenesis Imperfecta:** - Genetic defect in type I collagen (COL1A1, COL1A2 mutations). - Features: Fragile bones, blue sclerae, dentinogenesis imperfecta, hearing loss. - Autosomal dominant inheritance (most common forms).
152
What are the clinical types of osteogenesis imperfecta?
- **Clinical Types of OI:** - **Type I:** Mild, normal stature. - **Type II:** Perinatal lethal. - **Type III:** Severe, progressively deforming. - **Type IV:** Moderate severity. - Other rarer types involve recessive inheritance.
153
How is osteogenesis imperfecta diagnosed and managed?
- **Diagnosis and Management of OI:** - Diagnosis: Clinical features + bone density scans, genetic testing. - Management: Bisphosphonates (e.g., pamidronate), fracture prevention, physical therapy. - Surgical interventions for deformities (e.g., rodding).
154
What is juvenile osteoporosis, and how does it present?
- **Juvenile Osteoporosis:** - Rare, idiopathic condition. - Presents with bone pain, fractures, vertebral compression. - Usually resolves spontaneously around puberty. - Supportive management (calcium, vitamin D, physical therapy).
155
What are the causes of pathologic fractures in pediatrics?
- **Causes of Pathologic Fractures in Children:** - Osteogenesis imperfecta. - Nutritional rickets. - Juvenile osteoporosis. - Chronic illnesses (e.g., renal osteodystrophy, leukemia).
156
What is the evaluation approach for a child with recurrent fractures?
- **Evaluation of Recurrent Fractures:** - Detailed history and physical exam. - Labs: Calcium, phosphate, vitamin D, PTH. - Bone density scan (DEXA). - Skeletal survey if non-accidental trauma suspected.
157
What is fibrous dysplasia, and how does it present?
- **Fibrous Dysplasia:** - Replacement of normal bone with fibrous tissue. - Presents with bone pain, fractures, deformities. - Radiology: Ground-glass appearance on X-ray.
158
What are features of McCune-Albright syndrome related to bone health?
- **Bone Features in McCune-Albright Syndrome:** - Polyostotic fibrous dysplasia (multiple bones affected). - Pathologic fractures. - Associated with café-au-lait spots and endocrine abnormalities (precocious puberty).
159
What is osteopetrosis, and how does it affect calcium metabolism?
- **Osteopetrosis:** - Defective osteoclast-mediated bone resorption. - Features: Dense but brittle bones, hypocalcemia, anemia, hepatosplenomegaly. - Severe infantile forms may be fatal without bone marrow transplant.
160
What are the typical lab findings in hypoparathyroidism?
- **Lab Findings in Hypoparathyroidism:** - Low serum calcium. - High serum phosphate. - Low or inappropriately normal PTH levels. - Normal kidney function.
161
What are features and causes of hyperparathyroidism-jaw tumor syndrome?
- **Hyperparathyroidism-Jaw Tumor Syndrome:** - Rare autosomal dominant disorder. - Mutation in CDC73 gene. - Features: Parathyroid tumors, ossifying jaw fibromas, renal and uterine tumors.
162
What is the differential diagnosis of neonatal severe hyperparathyroidism?
- **Neonatal Severe Hyperparathyroidism Differential:** - Homozygous inactivating mutations in calcium-sensing receptor (CaSR). - Maternal hyperparathyroidism. - Genetic syndromes (e.g., familial hyperparathyroidism).
163
How does renal osteodystrophy develop in children with chronic kidney disease (CKD)?
- **Renal Osteodystrophy in CKD:** - CKD leads to phosphate retention, hypocalcemia, secondary hyperparathyroidism. - Disordered bone turnover and mineralization. - Elevated PTH and alkaline phosphatase.
164
What are the skeletal changes seen in renal osteodystrophy?
- **Skeletal Changes in Renal Osteodystrophy:** - Osteitis fibrosa cystica (high turnover bone disease). - Adynamic bone disease (low turnover if PTH suppression excessive). - Growth retardation, deformities.
165
How does hypomagnesemia affect calcium and PTH levels?
- **Hypomagnesemia Effects:** - Hypomagnesemia impairs PTH secretion and PTH action. - Leads to hypocalcemia and hypokalemia. - Must correct magnesium deficiency to normalize calcium.
166
What is tumor-induced osteomalacia, and how does it present?
- **Tumor-Induced Osteomalacia:** - Rare paraneoplastic syndrome. - Tumors produce excess FGF23 → phosphate wasting, low vitamin D. - Features: Bone pain, fractures, muscle weakness. - Labs: Hypophosphatemia, low 1,25(OH)2D, elevated FGF23.
167
What is the role of fibroblast growth factor 23 (FGF23) in phosphate metabolism?
- **FGF23 Role in Phosphate Metabolism:** - Secreted by osteocytes. - Inhibits renal phosphate reabsorption. - Suppresses 1α-hydroxylase, reducing active vitamin D levels. - Elevated in hypophosphatemic disorders.
168
What are features of familial hypocalciuric hypercalcemia (FHH)?
- **Familial Hypocalciuric Hypercalcemia (FHH) Features:** - Autosomal dominant CaSR mutation. - Mild hypercalcemia, low urinary calcium excretion. - Normal or mildly elevated PTH. - Asymptomatic; no treatment needed.
169
How is FHH distinguished from primary hyperparathyroidism?
- **Distinguishing FHH from Primary Hyperparathyroidism:** - **FHH:** Low urine calcium/creatinine clearance ratio (<0.01). - **Primary HPT:** Higher urinary calcium excretion (>0.02). - Family history helpful.
170
What are the genetic causes of primary hypoparathyroidism?
- **Genetic Causes of Primary Hypoparathyroidism:** - Autoimmune polyendocrine syndromes (APS-1). - Mutations in PTH gene. - Mutations in GCM2 gene (critical for parathyroid development).
171
What is the mechanism and features of hypocalcemia in DiGeorge syndrome?
- **DiGeorge Syndrome Hypocalcemia:** - 22q11.2 deletion → thymic aplasia/hypoplasia and parathyroid hypoplasia. - Features: Hypocalcemia (seizures, tetany), immunodeficiency, congenital heart defects.
172
How does vitamin D intoxication present clinically and biochemically in children?
- **Vitamin D Intoxication in Children:** - Clinical: Vomiting, poor feeding, constipation, polyuria, dehydration. - Biochemical: Hypercalcemia, low PTH, elevated 25(OH)D. - Management: Stop vitamin D, IV fluids, bisphosphonates if needed.
173
What are causes of elevated alkaline phosphatase in pediatrics besides bone disease?
- **Other Causes of Elevated Alkaline Phosphatase:** - Liver disease (hepatitis, biliary obstruction). - Rapid growth periods (puberty). - Hemolysis. - Placental production in pregnancy.
174
What are clinical and biochemical features of X-linked hypophosphatemia (XLH)?
- **X-linked Hypophosphatemia (XLH) Features:** - PHEX mutation → elevated FGF23. - Hypophosphatemia, normal calcium. - Rickets/osteomalacia, bone pain, dental abscesses.
175
What is the treatment strategy for X-linked hypophosphatemia?
- **Treatment of XLH:** - Oral phosphate supplements. - Active vitamin D (calcitriol or alfacalcidol). - Newer therapy: Burosumab (anti-FGF23 monoclonal antibody).
176
What is autosomal dominant hypophosphatemic rickets (ADHR), and how does it differ from XLH?
- **ADHR vs XLH:** - ADHR caused by FGF23 gene mutation (activating). - Later onset possible. - Clinical course may fluctuate with growth, puberty, and illness.
177
What is tumor-induced osteomalacia and how is it different from genetic hypophosphatemic rickets?
- **Tumor-Induced Osteomalacia vs Genetic Hypophosphatemia:** - Tumor-induced: Adult or late childhood onset, localized tumor producing FGF23. - Genetic rickets: Present from infancy or early childhood.
178
What is the presentation and management of hypophosphatasia in pediatrics?
- **Hypophosphatasia Presentation and Management:** - Deficiency of tissue non-specific alkaline phosphatase. - Features: Poor bone mineralization, fractures, craniosynostosis, dental problems. - Management: Enzyme replacement therapy (asfotase alfa).
179
What are skeletal manifestations of hyperparathyroidism in children?
- **Skeletal Manifestations of Hyperparathyroidism:** - Subperiosteal bone resorption. - Brown tumors. - Osteopenia/osteoporosis. - Pathologic fractures.
180
What is milk-alkali syndrome, and how does it cause hypercalcemia?
- **Milk-Alkali Syndrome:** - Excessive intake of calcium and absorbable alkali (e.g., antacids). - Hypercalcemia, metabolic alkalosis, renal impairment. - Treatment: Discontinue offending agents, IV hydration.
181
What are the skeletal complications of untreated rickets?
- **Skeletal Complications of Untreated Rickets:** - Permanent bowing of legs. - Short stature. - Genu valgum/varum. - Pelvic deformities. - Increased fracture risk.
182
What is the difference between calcipenic and phosphopenic rickets?
- **Calcipenic vs Phosphopenic Rickets:** - **Calcipenic:** Due to vitamin D deficiency → hypocalcemia → secondary hyperparathyroidism → hypophosphatemia. - **Phosphopenic:** Due to primary renal phosphate wasting (e.g., XLH); normal calcium, low phosphate.
183
How does chronic hypocalcemia affect dental development?
- **Chronic Hypocalcemia and Dental Development:** - Enamel hypoplasia. - Delayed eruption of teeth. - Increased dental caries. - Dental abscesses in absence of trauma (seen in XLH).
184
What is the role of magnesium in PTH secretion and action?
- **Magnesium's Role in PTH:** - Required for normal PTH secretion. - Severe hypomagnesemia → impaired PTH secretion and resistance at target tissues. - Correction of magnesium essential before correcting calcium.
185
What are typical findings in pseudopseudohypoparathyroidism?
- **Pseudopseudohypoparathyroidism:** - Physical phenotype of Albright hereditary osteodystrophy (short stature, brachydactyly) WITHOUT biochemical PTH resistance. - Normal calcium, phosphate, and PTH levels.
186
What endocrinopathies are associated with autoimmune polyendocrine syndrome type 1 (APS-1)?
- **APS-1 Endocrinopathies:** - Chronic mucocutaneous candidiasis. - Hypoparathyroidism. - Primary adrenal insufficiency. - Other autoimmune diseases (e.g., type 1 diabetes).
187
What is the skeletal impact of untreated hypoparathyroidism in children?
- **Skeletal Impact of Untreated Hypoparathyroidism:** - Increased bone mineral density (hypermineralization). - Risk of basal ganglia calcifications. - Possible increased fracture risk despite high bone density due to brittle bones.
188
What factors regulate FGF23 secretion in the body?
- **Regulation of FGF23 Secretion:** - Stimulated by high serum phosphate. - Stimulated by 1,25(OH)2 vitamin D. - Inhibited by hypophosphatemia.
189
What are the differences between vitamin D–dependent rickets type 1 and type 2 regarding lab findings?
- **Vitamin D–Dependent Rickets Type 1 vs Type 2 Labs:** - **Type 1:** Low 1,25(OH)2D (impaired synthesis). - **Type 2:** High 1,25(OH)2D (end-organ resistance).
190
What bone diseases are associated with celiac disease?
- **Bone Diseases Associated with Celiac Disease:** - Secondary osteoporosis due to malabsorption. - Increased fracture risk. - Nutritional rickets if vitamin D/calcium deficiency severe.
191
What are the neurological manifestations of chronic hypocalcemia in children?
- **Neurological Manifestations of Chronic Hypocalcemia:** - Seizures. - Tetany. - Neuromuscular irritability. - Psychiatric symptoms: anxiety, depression. - Basal ganglia calcifications (long term).
192
What is the pathogenesis of basal ganglia calcifications in hypoparathyroidism?
- **Basal Ganglia Calcifications in Hypoparathyroidism:** - Chronic low calcium and high phosphate levels promote calcium-phosphate deposition in brain tissue. - Leads to intracranial calcifications, primarily basal ganglia.
193
What skeletal features are seen in untreated hypophosphatemic rickets?
- **Skeletal Features of Untreated Hypophosphatemic Rickets:** - Leg bowing (genu varum). - Short stature. - Rachitic rosary. - Dental anomalies (abscesses, hypoplasia).
194
How does chronic hypercalcemia affect renal function?
- **Chronic Hypercalcemia and Renal Function:** - Nephrocalcinosis (calcium deposition in renal parenchyma). - Polyuria, dehydration. - Progressive renal insufficiency if untreated.
195
What endocrine syndromes are associated with medullary thyroid carcinoma and parathyroid disease?
- **Endocrine Syndromes with Parathyroid Disease:** - **MEN 1:** Parathyroid tumors, pancreatic tumors, pituitary tumors. - **MEN 2A:** Medullary thyroid carcinoma, pheochromocytoma, parathyroid hyperplasia.
196
How does malabsorption affect bone mineralization in children?
- **Malabsorption and Bone Health:** - Vitamin D and calcium malabsorption → secondary osteoporosis. - Common in celiac disease, cystic fibrosis, IBD. - Leads to poor bone mineralization and fracture risk.
197
What are causes of secondary osteoporosis in pediatrics?
- **Causes of Secondary Osteoporosis in Children:** - Chronic inflammatory diseases (e.g., JIA). - Glucocorticoid therapy. - Malabsorption syndromes. - Endocrine disorders (e.g., hypogonadism, hyperthyroidism).
198
What is the typical bone profile in chronic kidney disease–mineral and bone disorder (CKD-MBD)?
- **Bone Profile in CKD-MBD:** - Elevated phosphate. - Low or normal calcium. - Elevated PTH (secondary hyperparathyroidism). - Elevated alkaline phosphatase.
199
How does bisphosphonate therapy help in pediatric bone disorders?
- **Bisphosphonate Therapy in Pediatric Bone Disorders:** - Inhibits osteoclast-mediated bone resorption. - Increases bone density. - Reduces fracture rates in conditions like OI and juvenile osteoporosis.
200
What precautions should be taken during bisphosphonate therapy in children?
- **Precautions During Bisphosphonate Therapy:** - Monitor renal function. - Risk of hypocalcemia — ensure adequate vitamin D/calcium status. - Dental examination before initiation (risk of osteonecrosis of jaw rare but serious).
201
What is the basic anatomy and function of the adrenal gland?
- **Adrenal Gland Anatomy and Function:** - Located atop each kidney. - Adrenal cortex: Produces steroid hormones (cortisol, aldosterone, androgens). - Adrenal medulla: Produces catecholamines (epinephrine, norepinephrine).
202
What are the zones of the adrenal cortex and their hormone products?
- **Adrenal Cortex Zones:** - **Zona glomerulosa:** Aldosterone (salt balance). - **Zona fasciculata:** Cortisol (stress response, metabolism). - **Zona reticularis:** Androgens (sex steroids).
203
What is congenital adrenal hyperplasia (CAH)?
- **Congenital Adrenal Hyperplasia (CAH):** - Group of autosomal recessive disorders causing enzyme deficiencies in cortisol synthesis. - Leads to cortisol deficiency, ± aldosterone deficiency, ± androgen excess. - 21-hydroxylase deficiency accounts for >90% of cases.
204
What are the clinical features of classic 21-hydroxylase deficiency?
- **Classic 21-Hydroxylase Deficiency Features:** - Salt-wasting form: Hypovolemia, hyponatremia, hyperkalemia, shock. - Simple virilizing form: Ambiguous genitalia in girls, early puberty in boys. - Dehydration, failure to thrive if untreated.
205
How is classic 21-hydroxylase deficiency diagnosed?
- **Diagnosis of 21-Hydroxylase Deficiency:** - Elevated 17-hydroxyprogesterone (screened on newborn screening). - Electrolyte disturbances (salt-wasting form). - Genetic testing for CYP21A2 mutations (confirmatory).
206
How is classic CAH (salt-wasting and simple virilizing) managed?
- **Management of Classic CAH:** - Glucocorticoid replacement (hydrocortisone). - Mineralocorticoid replacement (fludrocortisone) and salt supplementation (if salt-wasting). - Stress dose steroids during illness/surgery. - Regular growth and hormone monitoring.
207
What is non-classic CAH, and how does it present?
- **Non-Classic CAH Presentation:** - Milder 21-hydroxylase deficiency. - Features: Premature adrenarche, hirsutism, menstrual irregularities, infertility. - Often diagnosed in adolescence or adulthood.
208
What is Addison disease in children, and what are its causes?
- **Addison Disease (Primary Adrenal Insufficiency):** - Destruction/dysfunction of adrenal cortex. - Causes: Autoimmune adrenalitis (most common), infections (TB), genetic syndromes (e.g., X-linked adrenoleukodystrophy).
209
What are the clinical features of adrenal crisis?
- **Clinical Features of Adrenal Crisis:** - Severe dehydration, hypotension, shock. - Hypoglycemia. - Hyponatremia, hyperkalemia. - Vomiting, abdominal pain.
210
How is acute adrenal crisis managed in children?
- **Management of Acute Adrenal Crisis:** - Immediate IV fluids (normal saline bolus). - IV hydrocortisone. - Correct hypoglycemia if present. - Identify and treat underlying precipitating factors.
211
What are causes of secondary adrenal insufficiency in children?
- **Causes of Secondary Adrenal Insufficiency:** - Pituitary tumors. - Craniopharyngioma. - Post-surgical or post-radiation. - Prolonged glucocorticoid therapy (suppression of HPA axis).
212
What is the difference between primary and secondary adrenal insufficiency?
- **Primary vs Secondary Adrenal Insufficiency:** - **Primary:** Problem in adrenal gland → Low cortisol, high ACTH. - **Secondary:** Problem in pituitary → Low cortisol, low/normal ACTH. - Aldosterone production preserved in secondary forms.
213
What is congenital adrenal hypoplasia, and how does it present?
- **Congenital Adrenal Hypoplasia:** - Rare X-linked disorder (DAX1/NR0B1 mutations). - Presents with adrenal insufficiency in infancy (salt-wasting crisis). - May also have hypogonadotropic hypogonadism later.
214
What is adrenal hemorrhage in neonates, and how does it present clinically?
- **Adrenal Hemorrhage in Neonates:** - Risk factors: Birth trauma, sepsis, hypoxia. - Presents with anemia, shock, abdominal mass. - May lead to adrenal insufficiency if bilateral.
215
What are the causes and features of Cushing syndrome in children?
- **Causes and Features of Cushing Syndrome:** - Causes: Exogenous steroids (most common), adrenal tumors, pituitary ACTH-producing tumors. - Features: Growth failure, obesity, moon facies, hypertension, striae, bruising.
216
What is the difference between Cushing disease and Cushing syndrome?
- **Cushing Disease vs Cushing Syndrome:** - **Cushing Syndrome:** General term for cortisol excess. - **Cushing Disease:** Specifically due to pituitary ACTH-secreting tumor.
217
How is Cushing syndrome diagnosed in pediatrics?
- **Diagnosis of Cushing Syndrome:** - Screening: 24-hour urinary free cortisol, low-dose dexamethasone suppression test, late-night salivary cortisol. - Confirmatory: ACTH level, imaging (MRI brain, adrenal imaging).
218
What is the management of Cushing disease in children?
- **Management of Cushing Disease:** - Surgical resection of pituitary adenoma (transsphenoidal surgery). - Medical therapy (ketoconazole, metyrapone) if surgery unsuccessful. - Lifelong follow-up for recurrence or adrenal insufficiency.
219
What is the most common adrenal tumor in children?
- **Most Common Adrenal Tumor in Children:** - Neuroblastoma (arises from adrenal medulla).
220
What are features of adrenocortical tumors (ACTs) in pediatrics?
- **Features of Adrenocortical Tumors (ACTs):** - Rare in children. - Can produce cortisol (Cushingoid features), androgens (virilization), or estrogens (precocious puberty). - Often large, heterogeneous adrenal mass on imaging.
221
What is the basic anatomy and function of the adrenal gland?
- **Adrenal Gland Anatomy and Function:** - Located atop each kidney. - Adrenal cortex: Produces steroid hormones (cortisol, aldosterone, androgens). - Adrenal medulla: Produces catecholamines (epinephrine, norepinephrine).
222
What are the zones of the adrenal cortex and their hormone products?
- **Adrenal Cortex Zones:** - **Zona glomerulosa:** Aldosterone (salt balance). - **Zona fasciculata:** Cortisol (stress response, metabolism). - **Zona reticularis:** Androgens (sex steroids).
223
What is congenital adrenal hyperplasia (CAH)?
- **Congenital Adrenal Hyperplasia (CAH):** - Group of autosomal recessive disorders causing enzyme deficiencies in cortisol synthesis. - Leads to cortisol deficiency, ± aldosterone deficiency, ± androgen excess. - 21-hydroxylase deficiency accounts for >90% of cases.
224
What are the clinical features of classic 21-hydroxylase deficiency?
- **Classic 21-Hydroxylase Deficiency Features:** - Salt-wasting form: Hypovolemia, hyponatremia, hyperkalemia, shock. - Simple virilizing form: Ambiguous genitalia in girls, early puberty in boys. - Dehydration, failure to thrive if untreated.
225
How is classic 21-hydroxylase deficiency diagnosed?
- **Diagnosis of 21-Hydroxylase Deficiency:** - Elevated 17-hydroxyprogesterone (screened on newborn screening). - Electrolyte disturbances (salt-wasting form). - Genetic testing for CYP21A2 mutations (confirmatory).
226
How is classic CAH (salt-wasting and simple virilizing) managed?
- **Management of Classic CAH:** - Glucocorticoid replacement (hydrocortisone). - Mineralocorticoid replacement (fludrocortisone) and salt supplementation (if salt-wasting). - Stress dose steroids during illness/surgery. - Regular growth and hormone monitoring.
227
What is non-classic CAH, and how does it present?
- **Non-Classic CAH Presentation:** - Milder 21-hydroxylase deficiency. - Features: Premature adrenarche, hirsutism, menstrual irregularities, infertility. - Often diagnosed in adolescence or adulthood.
228
What is Addison disease in children, and what are its causes?
- **Addison Disease (Primary Adrenal Insufficiency):** - Destruction/dysfunction of adrenal cortex. - Causes: Autoimmune adrenalitis (most common), infections (TB), genetic syndromes (e.g., X-linked adrenoleukodystrophy).
229
What are the clinical features of adrenal crisis?
- **Clinical Features of Adrenal Crisis:** - Severe dehydration, hypotension, shock. - Hypoglycemia. - Hyponatremia, hyperkalemia. - Vomiting, abdominal pain.
230
How is acute adrenal crisis managed in children?
- **Management of Acute Adrenal Crisis:** - Immediate IV fluids (normal saline bolus). - IV hydrocortisone. - Correct hypoglycemia if present. - Identify and treat underlying precipitating factors.
231
What are causes of secondary adrenal insufficiency in children?
- **Causes of Secondary Adrenal Insufficiency:** - Pituitary tumors. - Craniopharyngioma. - Post-surgical or post-radiation. - Prolonged glucocorticoid therapy (suppression of HPA axis).
232
What is the difference between primary and secondary adrenal insufficiency?
- **Primary vs Secondary Adrenal Insufficiency:** - **Primary:** Problem in adrenal gland → Low cortisol, high ACTH. - **Secondary:** Problem in pituitary → Low cortisol, low/normal ACTH. - Aldosterone production preserved in secondary forms.
233
What is congenital adrenal hypoplasia, and how does it present?
- **Congenital Adrenal Hypoplasia:** - Rare X-linked disorder (DAX1/NR0B1 mutations). - Presents with adrenal insufficiency in infancy (salt-wasting crisis). - May also have hypogonadotropic hypogonadism later.
234
What is adrenal hemorrhage in neonates, and how does it present clinically?
- **Adrenal Hemorrhage in Neonates:** - Risk factors: Birth trauma, sepsis, hypoxia. - Presents with anemia, shock, abdominal mass. - May lead to adrenal insufficiency if bilateral.
235
What are the causes and features of Cushing syndrome in children?
- **Causes and Features of Cushing Syndrome:** - Causes: Exogenous steroids (most common), adrenal tumors, pituitary ACTH-producing tumors. - Features: Growth failure, obesity, moon facies, hypertension, striae, bruising.
236
What is the difference between Cushing disease and Cushing syndrome?
- **Cushing Disease vs Cushing Syndrome:** - **Cushing Syndrome:** General term for cortisol excess. - **Cushing Disease:** Specifically due to pituitary ACTH-secreting tumor.
237
How is Cushing syndrome diagnosed in pediatrics?
- **Diagnosis of Cushing Syndrome:** - Screening: 24-hour urinary free cortisol, low-dose dexamethasone suppression test, late-night salivary cortisol. - Confirmatory: ACTH level, imaging (MRI brain, adrenal imaging).
238
What is the management of Cushing disease in children?
- **Management of Cushing Disease:** - Surgical resection of pituitary adenoma (transsphenoidal surgery). - Medical therapy (ketoconazole, metyrapone) if surgery unsuccessful. - Lifelong follow-up for recurrence or adrenal insufficiency.
239
What is the most common adrenal tumor in children?
- **Most Common Adrenal Tumor in Children:** - Neuroblastoma (arises from adrenal medulla).
240
What are features of adrenocortical tumors (ACTs) in pediatrics?
- **Features of Adrenocortical Tumors (ACTs):** - Rare in children. - Can produce cortisol (Cushingoid features), androgens (virilization), or estrogens (precocious puberty). - Often large, heterogeneous adrenal mass on imaging.
241
What are the causes of adrenal calcifications in neonates?
- **Causes of Adrenal Calcifications in Neonates:** - Adrenal hemorrhage (most common). - Infections (e.g., CMV, toxoplasmosis). - Congenital adrenal hyperplasia (rare).
242
What is adrenal insufficiency in septic neonates, and how is it managed?
- **Adrenal Insufficiency in Septic Neonates:** - Sepsis (especially meningococcemia) can cause adrenal hemorrhage and insufficiency. - Management: Early IV hydrocortisone + supportive therapy (fluids, vasopressors).
243
What are the features of Waterhouse-Friderichsen syndrome?
- **Waterhouse-Friderichsen Syndrome:** - Acute adrenal failure due to bilateral adrenal hemorrhage. - Classically associated with Neisseria meningitidis sepsis. - Presents with shock, purpura, DIC, rapid deterioration.
244
What are the causes and features of hyperaldosteronism in pediatrics?
- **Hyperaldosteronism Causes and Features:** - Primary: Aldosterone-producing adenoma, familial hyperaldosteronism. - Features: Hypertension, hypokalemia, metabolic alkalosis.
245
What is the difference between primary and secondary hyperaldosteronism?
- **Primary vs Secondary Hyperaldosteronism:** - **Primary:** Adrenal gland pathology (autonomous aldosterone production). - **Secondary:** Due to increased renin (e.g., renal artery stenosis, nephrotic syndrome).
246
What is glucocorticoid-remediable aldosteronism (GRA)?
- **Glucocorticoid-Remediable Aldosteronism (GRA):** - Familial hyperaldosteronism type 1. - Chimeric gene duplication causes aldosterone production under ACTH control. - Treated with low-dose glucocorticoids to suppress ACTH.
247
How does 11β-hydroxylase deficiency present in congenital adrenal hyperplasia?
- **11β-Hydroxylase Deficiency Presentation:** - CAH variant. - Features: Hypertension (due to deoxycorticosterone accumulation), virilization, low renin. - Elevated 11-deoxycortisol levels.
248
What are the features of 17α-hydroxylase deficiency in CAH?
- **17α-Hydroxylase Deficiency Features:** - Rare form of CAH. - Features: Hypertension, hypokalemia, sexual infantilism (lack of puberty). - Labs: Low cortisol, low androgens, high ACTH.
249
What are the causes of hypercortisolism due to adrenal tumors in children?
- **Hypercortisolism Due to Adrenal Tumors:** - Adrenocortical adenomas or carcinomas can produce excess cortisol. - Presentation: Cushingoid features without elevated ACTH (ACTH-independent Cushing syndrome).
250
What is the approach to adrenal incidentalomas in pediatrics?
- **Approach to Adrenal Incidentalomas:** - Assess for hormonal activity (cortisol, androgens, aldosterone if hypertensive). - Imaging features (size >4 cm, irregular borders) may suggest malignancy. - Surgical removal if functional or suspicious.
251
What is the basic anatomy and function of the adrenal gland?
- **Adrenal Gland Anatomy and Function:** - Located atop each kidney. - Adrenal cortex: Produces steroid hormones (cortisol, aldosterone, androgens). - Adrenal medulla: Produces catecholamines (epinephrine, norepinephrine).
252
What are the zones of the adrenal cortex and their hormone products?
- **Adrenal Cortex Zones:** - **Zona glomerulosa:** Aldosterone (salt balance). - **Zona fasciculata:** Cortisol (stress response, metabolism). - **Zona reticularis:** Androgens (sex steroids).
253
What is congenital adrenal hyperplasia (CAH)?
- **Congenital Adrenal Hyperplasia (CAH):** - Group of autosomal recessive disorders causing enzyme deficiencies in cortisol synthesis. - Leads to cortisol deficiency, ± aldosterone deficiency, ± androgen excess. - 21-hydroxylase deficiency accounts for >90% of cases.
254
What are the clinical features of classic 21-hydroxylase deficiency?
- **Classic 21-Hydroxylase Deficiency Features:** - Salt-wasting form: Hypovolemia, hyponatremia, hyperkalemia, shock. - Simple virilizing form: Ambiguous genitalia in girls, early puberty in boys. - Dehydration, failure to thrive if untreated.
255
How is classic 21-hydroxylase deficiency diagnosed?
- **Diagnosis of 21-Hydroxylase Deficiency:** - Elevated 17-hydroxyprogesterone (screened on newborn screening). - Electrolyte disturbances (salt-wasting form). - Genetic testing for CYP21A2 mutations (confirmatory).
256
How is classic CAH (salt-wasting and simple virilizing) managed?
- **Management of Classic CAH:** - Glucocorticoid replacement (hydrocortisone). - Mineralocorticoid replacement (fludrocortisone) and salt supplementation (if salt-wasting). - Stress dose steroids during illness/surgery. - Regular growth and hormone monitoring.
257
What is non-classic CAH, and how does it present?
- **Non-Classic CAH Presentation:** - Milder 21-hydroxylase deficiency. - Features: Premature adrenarche, hirsutism, menstrual irregularities, infertility. - Often diagnosed in adolescence or adulthood.
258
What is Addison disease in children, and what are its causes?
- **Addison Disease (Primary Adrenal Insufficiency):** - Destruction/dysfunction of adrenal cortex. - Causes: Autoimmune adrenalitis (most common), infections (TB), genetic syndromes (e.g., X-linked adrenoleukodystrophy).
259
What are the clinical features of adrenal crisis?
- **Clinical Features of Adrenal Crisis:** - Severe dehydration, hypotension, shock. - Hypoglycemia. - Hyponatremia, hyperkalemia. - Vomiting, abdominal pain.
260
How is acute adrenal crisis managed in children?
- **Management of Acute Adrenal Crisis:** - Immediate IV fluids (normal saline bolus). - IV hydrocortisone. - Correct hypoglycemia if present. - Identify and treat underlying precipitating factors.
261
What are causes of secondary adrenal insufficiency in children?
- **Causes of Secondary Adrenal Insufficiency:** - Pituitary tumors. - Craniopharyngioma. - Post-surgical or post-radiation. - Prolonged glucocorticoid therapy (suppression of HPA axis).
262
What is the difference between primary and secondary adrenal insufficiency?
- **Primary vs Secondary Adrenal Insufficiency:** - **Primary:** Problem in adrenal gland → Low cortisol, high ACTH. - **Secondary:** Problem in pituitary → Low cortisol, low/normal ACTH. - Aldosterone production preserved in secondary forms.
263
What is congenital adrenal hypoplasia, and how does it present?
- **Congenital Adrenal Hypoplasia:** - Rare X-linked disorder (DAX1/NR0B1 mutations). - Presents with adrenal insufficiency in infancy (salt-wasting crisis). - May also have hypogonadotropic hypogonadism later.
264
What is adrenal hemorrhage in neonates, and how does it present clinically?
- **Adrenal Hemorrhage in Neonates:** - Risk factors: Birth trauma, sepsis, hypoxia. - Presents with anemia, shock, abdominal mass. - May lead to adrenal insufficiency if bilateral.
265
What are the causes and features of Cushing syndrome in children?
- **Causes and Features of Cushing Syndrome:** - Causes: Exogenous steroids (most common), adrenal tumors, pituitary ACTH-producing tumors. - Features: Growth failure, obesity, moon facies, hypertension, striae, bruising.
266
What is the difference between Cushing disease and Cushing syndrome?
- **Cushing Disease vs Cushing Syndrome:** - **Cushing Syndrome:** General term for cortisol excess. - **Cushing Disease:** Specifically due to pituitary ACTH-secreting tumor.
267
How is Cushing syndrome diagnosed in pediatrics?
- **Diagnosis of Cushing Syndrome:** - Screening: 24-hour urinary free cortisol, low-dose dexamethasone suppression test, late-night salivary cortisol. - Confirmatory: ACTH level, imaging (MRI brain, adrenal imaging).
268
What is the management of Cushing disease in children?
- **Management of Cushing Disease:** - Surgical resection of pituitary adenoma (transsphenoidal surgery). - Medical therapy (ketoconazole, metyrapone) if surgery unsuccessful. - Lifelong follow-up for recurrence or adrenal insufficiency.
269
What is the most common adrenal tumor in children?
- **Most Common Adrenal Tumor in Children:** - Neuroblastoma (arises from adrenal medulla).
270
What are features of adrenocortical tumors (ACTs) in pediatrics?
- **Features of Adrenocortical Tumors (ACTs):** - Rare in children. - Can produce cortisol (Cushingoid features), androgens (virilization), or estrogens (precocious puberty). - Often large, heterogeneous adrenal mass on imaging.
271
What is the pathophysiology of adrenal insufficiency in autoimmune polyendocrine syndrome type 1 (APS-1)?
- **Adrenal Insufficiency in APS-1:** - APS-1 caused by mutations in the AIRE gene. - Features: Adrenal insufficiency (due to autoimmune adrenalitis), chronic mucocutaneous candidiasis, hypoparathyroidism, and other autoimmune conditions.
272
What are the features of an adrenal crisis in a child with known adrenal insufficiency?
- **Adrenal Crisis in Known Adrenal Insufficiency:** - Sudden worsening of symptoms: Fever, vomiting, hypotension, and confusion. - Caused by illness, infection, or missed medication dose. - Immediate treatment: IV hydrocortisone, fluids, and electrolytes.
273
What is the role of cortisol in the stress response in children?
- **Cortisol Role in Stress Response:** - Cortisol increases glucose production via gluconeogenesis. - Increases blood pressure by enhancing vascular response to catecholamines. - Reduces inflammation and modulates immune response.
274
What are common causes of primary aldosteronism in pediatric patients?
- **Common Causes of Primary Aldosteronism in Children:** - Aldosterone-producing adenomas. - Bilateral adrenal hyperplasia. - Familial hyperaldosteronism. - Features: Hypertension, hypokalemia, metabolic alkalosis.
275
How does congenital adrenal hyperplasia affect adrenal androgen secretion?
- **Congenital Adrenal Hyperplasia and Adrenal Androgen Secretion:** - 21-hydroxylase deficiency leads to excess androgen production. - Results in virilization (ambiguous genitalia in females, early puberty in males).
276
What is the role of the adrenal medulla in pediatric endocrinology?
- **Role of Adrenal Medulla in Pediatric Endocrinology:** - Produces catecholamines (epinephrine and norepinephrine). - Key in fight-or-flight response. - Medullary tumors (e.g., pheochromocytomas) can cause episodic hypertension and paroxysmal symptoms.
277
What are the typical findings in a child with an adrenal adenoma?
- **Adrenal Adenoma in Children:** - Benign tumor of the adrenal cortex. - Can produce cortisol (Cushing syndrome), aldosterone (hypertension), or androgens (virilization). - Diagnosis: Imaging (CT/MRI) and biochemical tests for hormone production.
278
What is the role of dexamethasone suppression test in diagnosing Cushing syndrome in children?
- **Dexamethasone Suppression Test in Cushing Syndrome:** - Tests feedback inhibition of ACTH. - **Cushing syndrome:** Lack of suppression with dexamethasone. - Helps differentiate between ACTH-dependent and ACTH-independent causes of Cushing syndrome.
279
What is the impact of adrenal tumors on pediatric growth and development?
- **Impact of Adrenal Tumors on Growth and Development:** - Can lead to early puberty or precocious puberty. - Cortisol-producing tumors may result in Cushingoid features (e.g., obesity, growth failure).
280
What are the diagnostic criteria for 3β-hydroxysteroid dehydrogenase deficiency in CAH?
- **Diagnostic Criteria for 3β-Hydroxysteroid Dehydrogenase Deficiency in CAH:** - Elevated 17-hydroxyprogesterone and androgens. - Lack of glucocorticoid and mineralocorticoid production. - Clinical features: Ambiguous genitalia, electrolyte imbalances, virilization.
281
What is the basic anatomy and function of the adrenal gland?
- **Adrenal Gland Anatomy and Function:** - Located atop each kidney. - Adrenal cortex: Produces steroid hormones (cortisol, aldosterone, androgens). - Adrenal medulla: Produces catecholamines (epinephrine, norepinephrine).
282
What are the zones of the adrenal cortex and their hormone products?
- **Adrenal Cortex Zones:** - **Zona glomerulosa:** Aldosterone (salt balance). - **Zona fasciculata:** Cortisol (stress response, metabolism). - **Zona reticularis:** Androgens (sex steroids).
283
What is congenital adrenal hyperplasia (CAH)?
- **Congenital Adrenal Hyperplasia (CAH):** - Group of autosomal recessive disorders causing enzyme deficiencies in cortisol synthesis. - Leads to cortisol deficiency, ± aldosterone deficiency, ± androgen excess. - 21-hydroxylase deficiency accounts for >90% of cases.
284
What are the clinical features of classic 21-hydroxylase deficiency?
- **Classic 21-Hydroxylase Deficiency Features:** - Salt-wasting form: Hypovolemia, hyponatremia, hyperkalemia, shock. - Simple virilizing form: Ambiguous genitalia in girls, early puberty in boys. - Dehydration, failure to thrive if untreated.
285
How is classic 21-hydroxylase deficiency diagnosed?
- **Diagnosis of 21-Hydroxylase Deficiency:** - Elevated 17-hydroxyprogesterone (screened on newborn screening). - Electrolyte disturbances (salt-wasting form). - Genetic testing for CYP21A2 mutations (confirmatory).
286
How is classic CAH (salt-wasting and simple virilizing) managed?
- **Management of Classic CAH:** - Glucocorticoid replacement (hydrocortisone). - Mineralocorticoid replacement (fludrocortisone) and salt supplementation (if salt-wasting). - Stress dose steroids during illness/surgery. - Regular growth and hormone monitoring.
287
What is non-classic CAH, and how does it present?
- **Non-Classic CAH Presentation:** - Milder 21-hydroxylase deficiency. - Features: Premature adrenarche, hirsutism, menstrual irregularities, infertility. - Often diagnosed in adolescence or adulthood.
288
What is Addison disease in children, and what are its causes?
- **Addison Disease (Primary Adrenal Insufficiency):** - Destruction/dysfunction of adrenal cortex. - Causes: Autoimmune adrenalitis (most common), infections (TB), genetic syndromes (e.g., X-linked adrenoleukodystrophy).
289
What are the clinical features of adrenal crisis?
- **Clinical Features of Adrenal Crisis:** - Severe dehydration, hypotension, shock. - Hypoglycemia. - Hyponatremia, hyperkalemia. - Vomiting, abdominal pain.
290
How is acute adrenal crisis managed in children?
- **Management of Acute Adrenal Crisis:** - Immediate IV fluids (normal saline bolus). - IV hydrocortisone. - Correct hypoglycemia if present. - Identify and treat underlying precipitating factors.
291
What are causes of secondary adrenal insufficiency in children?
- **Causes of Secondary Adrenal Insufficiency:** - Pituitary tumors. - Craniopharyngioma. - Post-surgical or post-radiation. - Prolonged glucocorticoid therapy (suppression of HPA axis).
292
What is the difference between primary and secondary adrenal insufficiency?
- **Primary vs Secondary Adrenal Insufficiency:** - **Primary:** Problem in adrenal gland → Low cortisol, high ACTH. - **Secondary:** Problem in pituitary → Low cortisol, low/normal ACTH. - Aldosterone production preserved in secondary forms.
293
What is congenital adrenal hypoplasia, and how does it present?
- **Congenital Adrenal Hypoplasia:** - Rare X-linked disorder (DAX1/NR0B1 mutations). - Presents with adrenal insufficiency in infancy (salt-wasting crisis). - May also have hypogonadotropic hypogonadism later.
294
What is adrenal hemorrhage in neonates, and how does it present clinically?
- **Adrenal Hemorrhage in Neonates:** - Risk factors: Birth trauma, sepsis, hypoxia. - Presents with anemia, shock, abdominal mass. - May lead to adrenal insufficiency if bilateral.
295
What are the causes and features of Cushing syndrome in children?
- **Causes and Features of Cushing Syndrome:** - Causes: Exogenous steroids (most common), adrenal tumors, pituitary ACTH-producing tumors. - Features: Growth failure, obesity, moon facies, hypertension, striae, bruising.
296
What is the difference between Cushing disease and Cushing syndrome?
- **Cushing Disease vs Cushing Syndrome:** - **Cushing Syndrome:** General term for cortisol excess. - **Cushing Disease:** Specifically due to pituitary ACTH-secreting tumor.
297
How is Cushing syndrome diagnosed in pediatrics?
- **Diagnosis of Cushing Syndrome:** - Screening: 24-hour urinary free cortisol, low-dose dexamethasone suppression test, late-night salivary cortisol. - Confirmatory: ACTH level, imaging (MRI brain, adrenal imaging).
298
What is the management of Cushing disease in children?
- **Management of Cushing Disease:** - Surgical resection of pituitary adenoma (transsphenoidal surgery). - Medical therapy (ketoconazole, metyrapone) if surgery unsuccessful. - Lifelong follow-up for recurrence or adrenal insufficiency.
299
What is the most common adrenal tumor in children?
- **Most Common Adrenal Tumor in Children:** - Neuroblastoma (arises from adrenal medulla).
300
What are features of adrenocortical tumors (ACTs) in pediatrics?
- **Features of Adrenocortical Tumors (ACTs):** - Rare in children. - Can produce cortisol (Cushingoid features), androgens (virilization), or estrogens (precocious puberty). - Often large, heterogeneous adrenal mass on imaging.
301
What are the causes of adrenal calcifications in neonates?
- **Causes of Adrenal Calcifications in Neonates:** - Adrenal hemorrhage (most common). - Infections (e.g., CMV, toxoplasmosis). - Congenital adrenal hyperplasia (rare).
302
What is adrenal insufficiency in septic neonates, and how is it managed?
- **Adrenal Insufficiency in Septic Neonates:** - Sepsis (especially meningococcemia) can cause adrenal hemorrhage and insufficiency. - Management: Early IV hydrocortisone + supportive therapy (fluids, vasopressors).
303
What are the features of Waterhouse-Friderichsen syndrome?
- **Waterhouse-Friderichsen Syndrome:** - Acute adrenal failure due to bilateral adrenal hemorrhage. - Classically associated with Neisseria meningitidis sepsis. - Presents with shock, purpura, DIC, rapid deterioration.
304
What are the causes and features of hyperaldosteronism in pediatrics?
- **Hyperaldosteronism Causes and Features:** - Primary: Aldosterone-producing adenoma, familial hyperaldosteronism. - Features: Hypertension, hypokalemia, metabolic alkalosis.
305
What is the difference between primary and secondary hyperaldosteronism?
- **Primary vs Secondary Hyperaldosteronism:** - **Primary:** Adrenal gland pathology (autonomous aldosterone production). - **Secondary:** Due to increased renin (e.g., renal artery stenosis, nephrotic syndrome).
306
What is glucocorticoid-remediable aldosteronism (GRA)?
- **Glucocorticoid-Remediable Aldosteronism (GRA):** - Familial hyperaldosteronism type 1. - Chimeric gene duplication causes aldosterone production under ACTH control. - Treated with low-dose glucocorticoids to suppress ACTH.
307
How does 11β-hydroxylase deficiency present in congenital adrenal hyperplasia?
- **11β-Hydroxylase Deficiency Presentation:** - CAH variant. - Features: Hypertension (due to deoxycorticosterone accumulation), virilization, low renin. - Elevated 11-deoxycortisol levels.
308
What are the features of 17α-hydroxylase deficiency in CAH?
- **17α-Hydroxylase Deficiency Features:** - Rare form of CAH. - Features: Hypertension, hypokalemia, sexual infantilism (lack of puberty). - Labs: Low cortisol, low androgens, high ACTH.
309
What are the causes of hypercortisolism due to adrenal tumors in children?
- **Hypercortisolism Due to Adrenal Tumors:** - Adrenocortical adenomas or carcinomas can produce excess cortisol. - Presentation: Cushingoid features without elevated ACTH (ACTH-independent Cushing syndrome).
310
What is the approach to adrenal incidentalomas in pediatrics?
- **Approach to Adrenal Incidentalomas:** - Assess for hormonal activity (cortisol, androgens, aldosterone if hypertensive). - Imaging features (size >4 cm, irregular borders) may suggest malignancy. - Surgical removal if functional or suspicious.
311
What is the pathophysiology of adrenal insufficiency in autoimmune polyendocrine syndrome type 1 (APS-1)?
- **Adrenal Insufficiency in APS-1:** - APS-1 caused by mutations in the AIRE gene. - Features: Adrenal insufficiency (due to autoimmune adrenalitis), chronic mucocutaneous candidiasis, hypoparathyroidism, and other autoimmune conditions.
312
What are the features of an adrenal crisis in a child with known adrenal insufficiency?
- **Adrenal Crisis in Known Adrenal Insufficiency:** - Sudden worsening of symptoms: Fever, vomiting, hypotension, and confusion. - Caused by illness, infection, or missed medication dose. - Immediate treatment: IV hydrocortisone, fluids, and electrolytes.
313
What is the role of cortisol in the stress response in children?
- **Cortisol Role in Stress Response:** - Cortisol increases glucose production via gluconeogenesis. - Increases blood pressure by enhancing vascular response to catecholamines. - Reduces inflammation and modulates immune response.
314
What are common causes of primary aldosteronism in pediatric patients?
- **Common Causes of Primary Aldosteronism in Children:** - Aldosterone-producing adenomas. - Bilateral adrenal hyperplasia. - Familial hyperaldosteronism. - Features: Hypertension, hypokalemia, metabolic alkalosis.
315
How does congenital adrenal hyperplasia affect adrenal androgen secretion?
- **Congenital Adrenal Hyperplasia and Adrenal Androgen Secretion:** - 21-hydroxylase deficiency leads to excess androgen production. - Results in virilization (ambiguous genitalia in females, early puberty in males).
316
What is the role of the adrenal medulla in pediatric endocrinology?
- **Role of Adrenal Medulla in Pediatric Endocrinology:** - Produces catecholamines (epinephrine and norepinephrine). - Key in fight-or-flight response. - Medullary tumors (e.g., pheochromocytomas) can cause episodic hypertension and paroxysmal symptoms.
317
What are the typical findings in a child with an adrenal adenoma?
- **Adrenal Adenoma in Children:** - Benign tumor of the adrenal cortex. - Can produce cortisol (Cushing syndrome), aldosterone (hypertension), or androgens (virilization). - Diagnosis: Imaging (CT/MRI) and biochemical tests for hormone production.
318
What is the role of dexamethasone suppression test in diagnosing Cushing syndrome in children?
- **Dexamethasone Suppression Test in Cushing Syndrome:** - Tests feedback inhibition of ACTH. - **Cushing syndrome:** Lack of suppression with dexamethasone. - Helps differentiate between ACTH-dependent and ACTH-independent causes of Cushing syndrome.
319
What is the impact of adrenal tumors on pediatric growth and development?
- **Impact of Adrenal Tumors on Growth and Development:** - Can lead to early puberty or precocious puberty. - Cortisol-producing tumors may result in Cushingoid features (e.g., obesity, growth failure).
320
What are the diagnostic criteria for 3β-hydroxysteroid dehydrogenase deficiency in CAH?
- **Diagnostic Criteria for 3β-Hydroxysteroid Dehydrogenase Deficiency in CAH:** - Elevated 17-hydroxyprogesterone and androgens. - Lack of glucocorticoid and mineralocorticoid production. - Clinical features: Ambiguous genitalia, electrolyte imbalances, virilization.
321
What is the difference between Cushing syndrome and pseudo-Cushing syndrome?
- **Cushing Syndrome vs Pseudo-Cushing Syndrome:** - **Cushing Syndrome:** ACTH-dependent or ACTH-independent hypercortisolism, typically due to adrenal tumors or pituitary adenomas. - **Pseudo-Cushing:** Associated with severe illness, depression, or alcoholism; cortisol levels are high, but suppression tests are positive.
322
How does bilateral adrenal hyperplasia present in pediatric patients?
- **Bilateral Adrenal Hyperplasia in Pediatrics:** - Adrenal glands become enlarged and produce excessive amounts of cortisol. - Often associated with primary hyperaldosteronism (aldosterone excess). - Features: Hypertension, hypokalemia, and hypernatremia.
323
What are the adrenal manifestations of McCune-Albright syndrome?
- **Adrenal Manifestations of McCune-Albright Syndrome:** - Polyostotic fibrous dysplasia (bone lesions), café-au-lait spots, and precocious puberty. - Adrenal involvement can include virilization and adrenocortical tumors.
324
How is adrenal insufficiency differentiated from Addison's disease in children?
- **Adrenal Insufficiency vs Addison's Disease in Children:** - **Adrenal Insufficiency:** General term for reduced cortisol production, may include autoimmune or secondary causes. - **Addison's Disease:** Specific cause is autoimmune destruction of the adrenal cortex; involves both glucocorticoid and mineralocorticoid deficiency.
325
What are the major diagnostic features of an adrenal tumor in a child?
- **Adrenal Tumor Diagnostic Features:** - Imaging (CT/MRI): Size, shape, and density of the adrenal mass. - Biochemical: Hormonal testing (cortisol, aldosterone, androgens) for functional tumors. - Malignant tumors may present with symptoms of excess hormone production and rapid growth.
326
How does glucocorticoid treatment affect the diagnosis of adrenal insufficiency?
- **Glucocorticoid Treatment and Adrenal Insufficiency Diagnosis:** - Long-term glucocorticoid therapy can suppress the HPA axis. - Must discontinue glucocorticoids gradually to assess for underlying adrenal insufficiency. - ACTH stimulation tests are used to assess adrenal reserve.
327
What are the complications of untreated congenital adrenal hyperplasia (CAH) in infancy?
- **Complications of Untreated CAH in Infancy:** - Salt-wasting crisis: Severe hyponatremia, hyperkalemia, shock. - Virilization in females (ambiguous genitalia). - Dehydration, failure to thrive, metabolic disturbances.
328
What is the role of ACTH stimulation testing in diagnosing adrenal disorders?
- **ACTH Stimulation Testing in Adrenal Disorders:** - Used to assess adrenal function by measuring cortisol levels after synthetic ACTH injection. - Normal response: Rapid rise in cortisol. - Delayed or blunted response indicates adrenal insufficiency.
329
How does 17α-hydroxylase deficiency present in children with CAH?
- **17α-Hydroxylase Deficiency in CAH:** - Results in cortisol and sex hormone deficiencies. - Features: Hypertension (due to excess mineralocorticoids), sexual infantilism, and low testosterone/estrogen levels. - Elevated ACTH levels due to loss of feedback inhibition.
330
What are the steps in the management of primary aldosteronism in pediatrics?
- **Management of Primary Aldosteronism in Pediatrics:** - Surgical removal of aldosterone-producing adenoma. - Medical management with aldosterone antagonists (e.g., spironolactone) if surgery not possible. - Correct electrolyte imbalances (hypokalemia).
331
What is the basic anatomy and function of the pituitary gland?
- **Pituitary Gland Anatomy and Function:** - Located at the base of the brain, the pituitary is a small gland that controls various endocrine functions. - Divided into anterior and posterior parts, with the anterior secreting key hormones like GH, ACTH, TSH, FSH, LH, and prolactin, and the posterior secreting oxytocin and vasopressin.
332
What are the main hormones secreted by the anterior pituitary?
- **Main Hormones Secreted by Anterior Pituitary:** - **Growth Hormone (GH):** Stimulates growth and development. - **Thyroid Stimulating Hormone (TSH):** Stimulates thyroid hormone production. - **Adrenocorticotropic Hormone (ACTH):** Stimulates cortisol production in the adrenal glands. - **Gonadotropins (FSH, LH):** Regulate gonadal function. - **Prolactin:** Stimulates milk production.
333
What is the role of growth hormone (GH) in pediatric development?
- **Role of Growth Hormone in Pediatric Development:** - GH stimulates linear growth by promoting cartilage and bone formation. - Increases protein synthesis and overall body growth. - Essential for normal pubertal development and metabolic function.
334
What are the causes of hypopituitarism in children?
- **Causes of Hypopituitarism in Children:** - Genetic disorders (e.g., mutations in GH receptor gene, PROP1 mutations). - Brain tumors (e.g., craniopharyngioma, glioma). - Head trauma or surgery near the pituitary. - Infections, inflammation (e.g., meningitis). - Congenital malformations of the pituitary or hypothalamus.
335
How does growth hormone deficiency (GHD) present in children?
- **Clinical Features of Growth Hormone Deficiency (GHD):** - Poor growth (height <3rd percentile). - Delayed bone age. - Short stature with normal weight-to-height ratio. - Low energy levels, fatigue. - Delayed puberty if untreated.
336
What are the key diagnostic tests for growth hormone deficiency?
- **Key Diagnostic Tests for GHD:** - **Growth measurements:** Serial height measurements over time. - **GH stimulation test:** GH response to pharmacological agents (e.g., arginine, clonidine). - **IGF-1 levels:** Low levels support diagnosis. - **MRI of pituitary:** To assess structural abnormalities.
337
What is the management approach for growth hormone deficiency?
- **Management of Growth Hormone Deficiency:** - **Growth hormone replacement therapy (GHRT):** Recombinant human GH (subcutaneous injections). - Dosing based on age, weight, and GH levels. - Monitor growth response regularly. - Address underlying causes of hypopituitarism if identified.
338
What are common causes of hyperprolactinemia in pediatric patients?
- **Common Causes of Hyperprolactinemia in Pediatric Patients:** - Prolactinomas (benign pituitary tumors). - Hypothyroidism (secondary hyperprolactinemia). - Medications (e.g., antipsychotics, antidepressants). - Stress or chronic illness. - Pregnancy and breastfeeding.
339
How is a prolactinoma diagnosed and treated in children?
- **Diagnosis and Treatment of Prolactinomas:** - **Diagnosis:** Elevated prolactin levels, MRI to identify pituitary tumor. - **Treatment:** Dopamine agonists (e.g., cabergoline) to decrease prolactin levels and shrink the tumor. - Surgery or radiation if medications fail.
340
What are the differences between congenital and acquired hypopituitarism?
- **Congenital vs Acquired Hypopituitarism:** - **Congenital:** Present at birth, often due to genetic mutations or structural malformations (e.g., septo-optic dysplasia). - **Acquired:** Results from trauma, tumors, infections, or other acquired conditions during childhood.
341
What is the basic anatomy and function of the pituitary gland?
- **Pituitary Gland Anatomy and Function:** - Located at the base of the brain, the pituitary is a small gland that controls various endocrine functions. - Divided into anterior and posterior parts, with the anterior secreting key hormones like GH, ACTH, TSH, FSH, LH, and prolactin, and the posterior secreting oxytocin and vasopressin.
342
What are the main hormones secreted by the anterior pituitary?
- **Main Hormones Secreted by Anterior Pituitary:** - **Growth Hormone (GH):** Stimulates growth and development. - **Thyroid Stimulating Hormone (TSH):** Stimulates thyroid hormone production. - **Adrenocorticotropic Hormone (ACTH):** Stimulates cortisol production in the adrenal glands. - **Gonadotropins (FSH, LH):** Regulate gonadal function. - **Prolactin:** Stimulates milk production.
343
What is the role of growth hormone (GH) in pediatric development?
- **Role of Growth Hormone in Pediatric Development:** - GH stimulates linear growth by promoting cartilage and bone formation. - Increases protein synthesis and overall body growth. - Essential for normal pubertal development and metabolic function.
344
What are the causes of hypopituitarism in children?
- **Causes of Hypopituitarism in Children:** - Genetic disorders (e.g., mutations in GH receptor gene, PROP1 mutations). - Brain tumors (e.g., craniopharyngioma, glioma). - Head trauma or surgery near the pituitary. - Infections, inflammation (e.g., meningitis). - Congenital malformations of the pituitary or hypothalamus.
345
How does growth hormone deficiency (GHD) present in children?
- **Clinical Features of Growth Hormone Deficiency (GHD):** - Poor growth (height <3rd percentile). - Delayed bone age. - Short stature with normal weight-to-height ratio. - Low energy levels, fatigue. - Delayed puberty if untreated.
346
What are the key diagnostic tests for growth hormone deficiency?
- **Key Diagnostic Tests for GHD:** - **Growth measurements:** Serial height measurements over time. - **GH stimulation test:** GH response to pharmacological agents (e.g., arginine, clonidine). - **IGF-1 levels:** Low levels support diagnosis. - **MRI of pituitary:** To assess structural abnormalities.
347
What is the management approach for growth hormone deficiency?
- **Management of Growth Hormone Deficiency:** - **Growth hormone replacement therapy (GHRT):** Recombinant human GH (subcutaneous injections). - Dosing based on age, weight, and GH levels. - Monitor growth response regularly. - Address underlying causes of hypopituitarism if identified.
348
What are common causes of hyperprolactinemia in pediatric patients?
- **Common Causes of Hyperprolactinemia in Pediatric Patients:** - Prolactinomas (benign pituitary tumors). - Hypothyroidism (secondary hyperprolactinemia). - Medications (e.g., antipsychotics, antidepressants). - Stress or chronic illness. - Pregnancy and breastfeeding.
349
How is a prolactinoma diagnosed and treated in children?
- **Diagnosis and Treatment of Prolactinomas:** - **Diagnosis:** Elevated prolactin levels, MRI to identify pituitary tumor. - **Treatment:** Dopamine agonists (e.g., cabergoline) to decrease prolactin levels and shrink the tumor. - Surgery or radiation if medications fail.
350
What are the differences between congenital and acquired hypopituitarism?
- **Congenital vs Acquired Hypopituitarism:** - **Congenital:** Present at birth, often due to genetic mutations or structural malformations (e.g., septo-optic dysplasia). - **Acquired:** Results from trauma, tumors, infections, or other acquired conditions during childhood.
351
What are the signs and symptoms of growth hormone excess in children?
- **Signs and Symptoms of GH Excess:** - Gigantism in children (excessive growth of long bones, tall stature). - Acromegaly in adolescents/adults (enlargement of hands, feet, and facial features). - Symptoms: Headaches, sweating, sleep apnea, joint pain, and soft tissue swelling.
352
What is the most common cause of growth hormone excess (gigantism/acromegaly) in children?
- **Most Common Cause of GH Excess in Children:** - Pituitary adenomas (benign tumors of the pituitary gland). - Most are somatotroph adenomas that secrete excess GH. - Rarely, can be associated with genetic syndromes like McCune-Albright syndrome.
353
How is growth hormone excess diagnosed in children?
- **Diagnosis of GH Excess in Children:** - **Screening tests:** Elevated serum IGF-1 (insulin-like growth factor). - **Confirmatory tests:** Oral glucose tolerance test (GH should decrease normally in response to glucose, but remains elevated in GH excess).
354
What is the treatment for growth hormone excess in children?
- **Treatment for Growth Hormone Excess:** - Surgery: Transsphenoidal resection of the pituitary adenoma. - Medical treatment: Somatostatin analogs (octreotide, lanreotide) to suppress GH secretion. - Dopamine agonists (bromocriptine) and GH receptor antagonists (pegvisomant) can also be used.
355
What is the role of prolactin in pediatric endocrine health?
- **Role of Prolactin in Pediatric Endocrine Health:** - Prolactin stimulates breast development and lactation during pregnancy and after birth. - In non-pregnant females and males, prolactin levels are generally low but can affect the menstrual cycle and fertility.
356
What are the causes of hyperprolactinemia in children?
- **Causes of Hyperprolactinemia in Children:** - Prolactinomas (benign pituitary tumors). - Medications (antipsychotics, antidepressants). - Hypothyroidism (secondary increase in TRH leading to increased prolactin). - Stress, pituitary stalk compression, and kidney disease.
357
What are the clinical features of a prolactinoma in children?
- **Clinical Features of a Prolactinoma in Children:** - Females: Menstrual irregularities, galactorrhea (milk production).- Males: Erectile dysfunction, infertility, gynecomastia. - Both sexes: Visual disturbances (if tumor compresses optic chiasm).
358
What are the diagnostic tests used to confirm a prolactinoma in children?
- **Diagnostic Tests for Prolactinoma:** - Serum prolactin levels (significantly elevated in prolactinoma). - MRI of the pituitary gland to visualize tumor size and location.
359
How is a prolactinoma treated in pediatric patients?
- **Treatment of Prolactinoma in Pediatrics:** - Medical treatment: Dopamine agonists (cabergoline, bromocriptine) to reduce prolactin levels and shrink the tumor. - Surgical resection if the tumor is resistant to medication or if causing visual disturbances.
360
What is Sheehan syndrome, and how does it present in children?
- **Sheehan Syndrome in Children:** - Rare cause of pituitary insufficiency following postpartum hemorrhage. - Presents with symptoms of hypopituitarism, including growth failure, hypothyroidism, adrenal insufficiency, and secondary amenorrhea. - Diagnosis: MRI of pituitary, pituitary hormone testing.
361
What is the basic anatomy and function of the pituitary gland?
- **Pituitary Gland Anatomy and Function:** - Located at the base of the brain, the pituitary is a small gland that controls various endocrine functions. - Divided into anterior and posterior parts, with the anterior secreting key hormones like GH, ACTH, TSH, FSH, LH, and prolactin, and the posterior secreting oxytocin and vasopressin.
362
What are the main hormones secreted by the anterior pituitary?
- **Main Hormones Secreted by Anterior Pituitary:** - **Growth Hormone (GH):** Stimulates growth and development. - **Thyroid Stimulating Hormone (TSH):** Stimulates thyroid hormone production. - **Adrenocorticotropic Hormone (ACTH):** Stimulates cortisol production in the adrenal glands. - **Gonadotropins (FSH, LH):** Regulate gonadal function. - **Prolactin:** Stimulates milk production.
363
What is the role of growth hormone (GH) in pediatric development?
- **Role of Growth Hormone in Pediatric Development:** - GH stimulates linear growth by promoting cartilage and bone formation. - Increases protein synthesis and overall body growth. - Essential for normal pubertal development and metabolic function.
364
What are the causes of hypopituitarism in children?
- **Causes of Hypopituitarism in Children:** - Genetic disorders (e.g., mutations in GH receptor gene, PROP1 mutations). - Brain tumors (e.g., craniopharyngioma, glioma). - Head trauma or surgery near the pituitary. - Infections, inflammation (e.g., meningitis). - Congenital malformations of the pituitary or hypothalamus.
365
How does growth hormone deficiency (GHD) present in children?
- **Clinical Features of Growth Hormone Deficiency (GHD):** - Poor growth (height <3rd percentile). - Delayed bone age. - Short stature with normal weight-to-height ratio. - Low energy levels, fatigue. - Delayed puberty if untreated.
366
What are the key diagnostic tests for growth hormone deficiency?
- **Key Diagnostic Tests for GHD:** - **Growth measurements:** Serial height measurements over time. - **GH stimulation test:** GH response to pharmacological agents (e.g., arginine, clonidine). - **IGF-1 levels:** Low levels support diagnosis. - **MRI of pituitary:** To assess structural abnormalities.
367
What is the management approach for growth hormone deficiency?
- **Management of Growth Hormone Deficiency:** - **Growth hormone replacement therapy (GHRT):** Recombinant human GH (subcutaneous injections). - Dosing based on age, weight, and GH levels. - Monitor growth response regularly. - Address underlying causes of hypopituitarism if identified.
368
What are common causes of hyperprolactinemia in pediatric patients?
- **Common Causes of Hyperprolactinemia in Pediatric Patients:** - Prolactinomas (benign pituitary tumors). - Hypothyroidism (secondary hyperprolactinemia). - Medications (e.g., antipsychotics, antidepressants). - Stress or chronic illness. - Pregnancy and breastfeeding.
369
How is a prolactinoma diagnosed and treated in children?
- **Diagnosis and Treatment of Prolactinomas:** - **Diagnosis:** Elevated prolactin levels, MRI to identify pituitary tumor. - **Treatment:** Dopamine agonists (e.g., cabergoline) to decrease prolactin levels and shrink the tumor. - Surgery or radiation if medications fail.
370
What are the differences between congenital and acquired hypopituitarism?
- **Congenital vs Acquired Hypopituitarism:** - **Congenital:** Present at birth, often due to genetic mutations or structural malformations (e.g., septo-optic dysplasia). - **Acquired:** Results from trauma, tumors, infections, or other acquired conditions during childhood.
371
What are the signs and symptoms of growth hormone excess in children?
- **Signs and Symptoms of GH Excess:** - Gigantism in children (excessive growth of long bones, tall stature). - Acromegaly in adolescents/adults (enlargement of hands, feet, and facial features). - Symptoms: Headaches, sweating, sleep apnea, joint pain, and soft tissue swelling.
372
What is the most common cause of growth hormone excess (gigantism/acromegaly) in children?
- **Most Common Cause of GH Excess in Children:** - Pituitary adenomas (benign tumors of the pituitary gland). - Most are somatotroph adenomas that secrete excess GH. - Rarely, can be associated with genetic syndromes like McCune-Albright syndrome.
373
How is growth hormone excess diagnosed in children?
- **Diagnosis of GH Excess in Children:** - **Screening tests:** Elevated serum IGF-1 (insulin-like growth factor). - **Confirmatory tests:** Oral glucose tolerance test (GH should decrease normally in response to glucose, but remains elevated in GH excess).
374
What is the treatment for growth hormone excess in children?
- **Treatment for Growth Hormone Excess:** - Surgery: Transsphenoidal resection of the pituitary adenoma. - Medical treatment: Somatostatin analogs (octreotide, lanreotide) to suppress GH secretion. - Dopamine agonists (bromocriptine) and GH receptor antagonists (pegvisomant) can also be used.
375
What is the role of prolactin in pediatric endocrine health?
- **Role of Prolactin in Pediatric Endocrine Health:** - Prolactin stimulates breast development and lactation during pregnancy and after birth. - In non-pregnant females and males, prolactin levels are generally low but can affect the menstrual cycle and fertility.
376
What are the causes of hyperprolactinemia in children?
- **Causes of Hyperprolactinemia in Children:** - Prolactinomas (benign pituitary tumors). - Medications (antipsychotics, antidepressants). - Hypothyroidism (secondary increase in TRH leading to increased prolactin). - Stress, pituitary stalk compression, and kidney disease.
377
What are the clinical features of a prolactinoma in children?
- **Clinical Features of a Prolactinoma in Children:** - Females: Menstrual irregularities, galactorrhea (milk production).- Males: Erectile dysfunction, infertility, gynecomastia. - Both sexes: Visual disturbances (if tumor compresses optic chiasm).
378
What are the diagnostic tests used to confirm a prolactinoma in children?
- **Diagnostic Tests for Prolactinoma:** - Serum prolactin levels (significantly elevated in prolactinoma). - MRI of the pituitary gland to visualize tumor size and location.
379
How is a prolactinoma treated in pediatric patients?
- **Treatment of Prolactinoma in Pediatrics:** - Medical treatment: Dopamine agonists (cabergoline, bromocriptine) to reduce prolactin levels and shrink the tumor. - Surgical resection if the tumor is resistant to medication or if causing visual disturbances.
380
What is Sheehan syndrome, and how does it present in children?
- **Sheehan Syndrome in Children:** - Rare cause of pituitary insufficiency following postpartum hemorrhage. - Presents with symptoms of hypopituitarism, including growth failure, hypothyroidism, adrenal insufficiency, and secondary amenorrhea. - Diagnosis: MRI of pituitary, pituitary hormone testing.
381
What is the basic anatomy and function of the gonads (ovaries and testes)?
- **Anatomy and Function of Gonads:** - **Ovaries:** Produce eggs, estrogen, and progesterone. Regulate menstrual cycles and support pregnancy. - **Testes:** Produce sperm and testosterone. Regulate male secondary sexual characteristics, spermatogenesis, and libido.
382
What is the difference between primary and secondary hypogonadism?
- **Primary vs Secondary Hypogonadism:** - **Primary Hypogonadism:** Gonadal failure due to intrinsic gonadal disease (e.g., Turner syndrome, Klinefelter syndrome). - **Secondary Hypogonadism:** Due to pituitary or hypothalamic dysfunction (e.g., GnRH deficiency, tumors).
383
What are the clinical features of Turner syndrome in girls?
- **Clinical Features of Turner Syndrome:** - Short stature, webbed neck, low-set ears, and broad chest. - Primary amenorrhea, lack of secondary sexual characteristics. - Congenital heart defects (e.g., coarctation of the aorta), renal abnormalities.
384
What is the management approach for Turner syndrome?
- **Management of Turner Syndrome:** - Growth hormone therapy for short stature. - Estrogen replacement therapy for puberty induction. - Regular monitoring for cardiac and renal issues. - Fertility options (egg donation or oocyte preservation) if desired.
385
What is Klinefelter syndrome and how does it affect males?
- **Klinefelter Syndrome and Effects in Males:** - 47,XXY karyotype, leading to an extra X chromosome in males. - Features: Tall stature, hypogonadism, infertility, learning difficulties. - Decreased testosterone levels, gynecomastia, and reduced secondary male sexual characteristics.
386
What is the clinical presentation and management of Klinefelter syndrome?
- **Clinical Presentation and Management of Klinefelter Syndrome:** - Testosterone replacement therapy to induce secondary sexual characteristics. - Addressing infertility (sperm banking or assisted reproductive technologies). - Speech therapy and educational support for learning difficulties.
387
What is androgen insensitivity syndrome and its presentation in children?
- **Androgen Insensitivity Syndrome (AIS):** - A condition where the body is unable to respond to androgens (testosterone) despite having XY chromosomes. - Features in females: Normal external female genitalia, absent menstruation, normal breast development, absent pubic hair.
388
How is androgen insensitivity syndrome diagnosed and managed?
- **Diagnosis and Management of AIS:** - Diagnosis: Karyotype analysis (46,XY), serum testosterone levels, and absence of uterus on pelvic ultrasound. - Management: Gonadectomy after puberty to prevent gonadal tumors, estrogen replacement for feminization.
389
What are disorders of sexual differentiation (DSDs) and how are they classified?
- **Disorders of Sexual Differentiation (DSDs):** - Conditions where there is discordance between chromosomal, gonadal, and phenotypic sex. - Classified as 46,XY DSD, 46,XX DSD, or sex chromosome DSD (e.g., Turner, Klinefelter syndrome).
390
What are the causes and diagnosis of precocious puberty in children?
- **Causes and Diagnosis of Precocious Puberty:** - Early activation of the hypothalamic-pituitary-gonadal axis. - Causes: Central (idiopathic, CNS lesions), peripheral (gonadal tumors, McCune-Albright syndrome). - Diagnosis: Bone age radiographs, GnRH stimulation test, MRI of the brain.
391
What is delayed puberty, and what are its causes?
- **Delayed Puberty and Causes:** - Delay in the onset of puberty (lack of secondary sexual characteristics by age 14 in girls or age 15 in boys). - Causes: Constitutional delay (most common), hypogonadotropic hypogonadism, hypergonadotropic hypogonadism, chronic illness, malnutrition.
392
What are the features of constitutional delay of growth and puberty (CDGP)?
- **Features of Constitutional Delay of Growth and Puberty (CDGP):** - Normal growth velocity until delayed puberty. - Delayed bone age. - Family history of delayed puberty. - Normal development after puberty onset (late but normal growth and maturation).
393
What is the management approach for constitutional delay of growth and puberty?
- **Management of Constitutional Delay of Growth and Puberty:** - **No treatment necessary** for most cases. - If necessary, low-dose estrogen or testosterone therapy can be used to induce puberty and address psychosocial concerns.
394
What is the difference between central and peripheral precocious puberty?
- **Central vs Peripheral Precocious Puberty:** - **Central Precocious Puberty:** Early activation of hypothalamic-pituitary-gonadal axis (e.g., idiopathic, CNS lesions). - **Peripheral Precocious Puberty:** Early secretion of sex steroids (e.g., ovarian or adrenal tumors).
395
How is central precocious puberty diagnosed and treated?
- **Diagnosis and Treatment of Central Precocious Puberty:** - Diagnosis: Bone age radiographs, GnRH stimulation test (increased LH and FSH). - Treatment: GnRH analogs (leuprolide) to suppress puberty and prevent early epiphyseal closure.
396
What are the causes of androgen insensitivity syndrome (AIS)?
- **Causes of Androgen Insensitivity Syndrome (AIS):** - Mutations in the androgen receptor gene (AR) on the X chromosome. - Complete AIS: XY chromosomes with female phenotype. - Partial AIS: Mild degree of virilization or ambiguous genitalia.
397
What are the clinical features of Turner syndrome in the newborn period?
- **Clinical Features of Turner Syndrome in the Newborn Period:** - Lymphedema, webbed neck, low-set ears, and wide-spaced nipples. - Short stature and infertility. - Congenital heart defects (e.g., coarctation of the aorta) may be present.
398
What is the role of genetic testing in diagnosing gonadal disorders?
- **Role of Genetic Testing in Diagnosing Gonadal Disorders:** - Genetic testing can identify chromosomal abnormalities (e.g., 46,XX DSD, 46,XY DSD, Turner syndrome, Klinefelter syndrome). - Identifying mutations in androgen receptor genes for AIS or mutations in CYP21A2 for CAH.
399
What are the features of non-classical congenital adrenal hyperplasia (CAH) in females?
- **Features of Non-Classical CAH in Females:** - Present with mild virilization: hirsutism, acne, menstrual irregularities. - Typically diagnosed in adolescence or adulthood. - Elevated 17-hydroxyprogesterone during stress or after ACTH stimulation.
400
What is the management of ambiguous genitalia in a newborn with suspected DSD (disorders of sex development)?
- **Management of Ambiguous Genitalia in a Newborn with Suspected DSD:** - Immediate comprehensive evaluation including genetic testing, hormone levels (testosterone, estrogen, androgens), and imaging (ultrasound). - Multidisciplinary team approach (endocrinologist, geneticist, surgeon) for gender assignment, counseling, and treatment options.
401
What is the basic anatomy and function of the gonads (ovaries and testes)?
- **Anatomy and Function of Gonads:** - **Ovaries:** Produce eggs, estrogen, and progesterone. Regulate menstrual cycles and support pregnancy. - **Testes:** Produce sperm and testosterone. Regulate male secondary sexual characteristics, spermatogenesis, and libido.
402
What is the difference between primary and secondary hypogonadism?
- **Primary vs Secondary Hypogonadism:** - **Primary Hypogonadism:** Gonadal failure due to intrinsic gonadal disease (e.g., Turner syndrome, Klinefelter syndrome). - **Secondary Hypogonadism:** Due to pituitary or hypothalamic dysfunction (e.g., GnRH deficiency, tumors).
403
What are the clinical features of Turner syndrome in girls?
- **Clinical Features of Turner Syndrome:** - Short stature, webbed neck, low-set ears, and broad chest. - Primary amenorrhea, lack of secondary sexual characteristics. - Congenital heart defects (e.g., coarctation of the aorta), renal abnormalities.
404
What is the management approach for Turner syndrome?
- **Management of Turner Syndrome:** - Growth hormone therapy for short stature. - Estrogen replacement therapy for puberty induction. - Regular monitoring for cardiac and renal issues. - Fertility options (egg donation or oocyte preservation) if desired.
405
What is Klinefelter syndrome and how does it affect males?
- **Klinefelter Syndrome and Effects in Males:** - 47,XXY karyotype, leading to an extra X chromosome in males. - Features: Tall stature, hypogonadism, infertility, learning difficulties. - Decreased testosterone levels, gynecomastia, and reduced secondary male sexual characteristics.
406
What is the clinical presentation and management of Klinefelter syndrome?
- **Clinical Presentation and Management of Klinefelter Syndrome:** - Testosterone replacement therapy to induce secondary sexual characteristics. - Addressing infertility (sperm banking or assisted reproductive technologies). - Speech therapy and educational support for learning difficulties.
407
What is androgen insensitivity syndrome and its presentation in children?
- **Androgen Insensitivity Syndrome (AIS):** - A condition where the body is unable to respond to androgens (testosterone) despite having XY chromosomes. - Features in females: Normal external female genitalia, absent menstruation, normal breast development, absent pubic hair.
408
How is androgen insensitivity syndrome diagnosed and managed?
- **Diagnosis and Management of AIS:** - Diagnosis: Karyotype analysis (46,XY), serum testosterone levels, and absence of uterus on pelvic ultrasound. - Management: Gonadectomy after puberty to prevent gonadal tumors, estrogen replacement for feminization.
409
What are disorders of sexual differentiation (DSDs) and how are they classified?
- **Disorders of Sexual Differentiation (DSDs):** - Conditions where there is discordance between chromosomal, gonadal, and phenotypic sex. - Classified as 46,XY DSD, 46,XX DSD, or sex chromosome DSD (e.g., Turner, Klinefelter syndrome).
410
What are the causes and diagnosis of precocious puberty in children?
- **Causes and Diagnosis of Precocious Puberty:** - Early activation of the hypothalamic-pituitary-gonadal axis. - Causes: Central (idiopathic, CNS lesions), peripheral (gonadal tumors, McCune-Albright syndrome). - Diagnosis: Bone age radiographs, GnRH stimulation test, MRI of the brain.
411
What is delayed puberty, and what are its causes?
- **Delayed Puberty and Causes:** - Delay in the onset of puberty (lack of secondary sexual characteristics by age 14 in girls or age 15 in boys). - Causes: Constitutional delay (most common), hypogonadotropic hypogonadism, hypergonadotropic hypogonadism, chronic illness, malnutrition.
412
What are the features of constitutional delay of growth and puberty (CDGP)?
- **Features of Constitutional Delay of Growth and Puberty (CDGP):** - Normal growth velocity until delayed puberty. - Delayed bone age. - Family history of delayed puberty. - Normal development after puberty onset (late but normal growth and maturation).
413
What is the management approach for constitutional delay of growth and puberty?
- **Management of Constitutional Delay of Growth and Puberty:** - **No treatment necessary** for most cases. - If necessary, low-dose estrogen or testosterone therapy can be used to induce puberty and address psychosocial concerns.
414
What is the difference between central and peripheral precocious puberty?
- **Central vs Peripheral Precocious Puberty:** - **Central Precocious Puberty:** Early activation of hypothalamic-pituitary-gonadal axis (e.g., idiopathic, CNS lesions). - **Peripheral Precocious Puberty:** Early secretion of sex steroids (e.g., ovarian or adrenal tumors).
415
How is central precocious puberty diagnosed and treated?
- **Diagnosis and Treatment of Central Precocious Puberty:** - Diagnosis: Bone age radiographs, GnRH stimulation test (increased LH and FSH). - Treatment: GnRH analogs (leuprolide) to suppress puberty and prevent early epiphyseal closure.
416
What are the causes of androgen insensitivity syndrome (AIS)?
- **Causes of Androgen Insensitivity Syndrome (AIS):** - Mutations in the androgen receptor gene (AR) on the X chromosome. - Complete AIS: XY chromosomes with female phenotype. - Partial AIS: Mild degree of virilization or ambiguous genitalia.
417
What are the clinical features of Turner syndrome in the newborn period?
- **Clinical Features of Turner Syndrome in the Newborn Period:** - Lymphedema, webbed neck, low-set ears, and wide-spaced nipples. - Short stature and infertility. - Congenital heart defects (e.g., coarctation of the aorta) may be present.
418
What is the role of genetic testing in diagnosing gonadal disorders?
- **Role of Genetic Testing in Diagnosing Gonadal Disorders:** - Genetic testing can identify chromosomal abnormalities (e.g., 46,XX DSD, 46,XY DSD, Turner syndrome, Klinefelter syndrome). - Identifying mutations in androgen receptor genes for AIS or mutations in CYP21A2 for CAH.
419
What are the features of non-classical congenital adrenal hyperplasia (CAH) in females?
- **Features of Non-Classical CAH in Females:** - Present with mild virilization: hirsutism, acne, menstrual irregularities. - Typically diagnosed in adolescence or adulthood. - Elevated 17-hydroxyprogesterone during stress or after ACTH stimulation.
420
What is the management of ambiguous genitalia in a newborn with suspected DSD (disorders of sex development)?
- **Management of Ambiguous Genitalia in a Newborn with Suspected DSD:** - Immediate comprehensive evaluation including genetic testing, hormone levels (testosterone, estrogen, androgens), and imaging (ultrasound). - Multidisciplinary team approach (endocrinologist, geneticist, surgeon) for gender assignment, counseling, and treatment options.
421
What are the common causes of delayed puberty in boys?
- **Common Causes of Delayed Puberty in Boys:** - Constitutional delay (most common). - Hypogonadotropic hypogonadism (e.g., Kallmann syndrome). - Hypergonadotropic hypogonadism (e.g., Klinefelter syndrome).
422
How does constitutional delay of puberty differ from hypogonadotropic hypogonadism?
- **Constitutional Delay vs Hypogonadotropic Hypogonadism:** - **Constitutional Delay:** Family history of late puberty, normal growth velocity, delayed bone age. - **Hypogonadotropic Hypogonadism:** Secondary failure of the hypothalamus or pituitary (e.g., Kallmann syndrome, idiopathic).
423
What are the features of McCune-Albright syndrome in pediatric patients?
- **Features of McCune-Albright Syndrome:** - **Classic triad:** Polyostotic fibrous dysplasia, café-au-lait spots, and precocious puberty. - Gonadotropin-independent precocious puberty due to activating mutations in the GNAS gene.
424
What is the role of GnRH analogs in the treatment of precocious puberty?
- **Role of GnRH Analogs in Precocious Puberty:** - Used to suppress the premature activation of the hypothalamic-pituitary-gonadal axis. - Prevents early bone maturation and helps normalize growth velocity. - Medications: Leuprolide, triptorelin.
425
What are the causes of hypergonadotropic hypogonadism?
- **Causes of Hypergonadotropic Hypogonadism:** - Gonadal failure (e.g., Turner syndrome, Klinefelter syndrome, autoimmune gonadal damage). - Results in elevated FSH and LH with low gonadal hormones (e.g., estrogen or testosterone).
426
What is the role of genetic testing in diagnosing gonadal disorders?
- **Role of Genetic Testing in Diagnosing Gonadal Disorders:** - Identifies chromosomal abnormalities (e.g., 46,XX or 46,XY DSD, Turner syndrome, Klinefelter syndrome). - Helps with identifying mutations in the androgen receptor gene for AIS or in the CYP21A2 gene for CAH.
427
What are the key features of Turner syndrome in adolescence?
- **Key Features of Turner Syndrome in Adolescence:** - Short stature, lack of pubertal development, and infertility. - Cardiovascular abnormalities (e.g., coarctation of the aorta). - Management: Estrogen replacement therapy to induce puberty and optimize bone health.
428
What is the typical treatment plan for a child with Klinefelter syndrome?
- **Treatment Plan for Klinefelter Syndrome:** - Testosterone replacement therapy to induce secondary sexual characteristics and promote growth. - Fertility options, such as sperm banking. - Educational support for developmental and learning difficulties.
429
What are the management strategies for ambiguous genitalia in a newborn with DSD?
- **Management Strategies for Ambiguous Genitalia in DSD:** - Multidisciplinary team approach (endocrinologists, geneticists, surgeons). - Genetic testing to determine chromosomal sex and appropriate gender assignment. - Hormone therapy and/or surgery as needed for gender affirmation and reproductive function.
430
How does 46,XY DSD with complete androgen insensitivity syndrome (CAIS) present in childhood?
- **46,XY DSD with Complete Androgen Insensitivity Syndrome (CAIS) Presentation:** - XY chromosomes with female external genitalia. - Normal breast development, absent pubic and axillary hair. - Diagnosis: Karyotyping, androgen receptor gene mutation analysis, and pelvic ultrasound.
431
What are the causes and diagnosis of delayed puberty in girls?
- **Causes and Diagnosis of Delayed Puberty in Girls:** - Causes: Constitutional delay, Turner syndrome, hypogonadotropic hypogonadism, anorexia nervosa, and chronic illness. - Diagnosis: Evaluation of growth curve, bone age, and serum gonadotropin levels (FSH, LH).
432
How is hypogonadotropic hypogonadism treated in children?
- **Treatment of Hypogonadotropic Hypogonadism in Children:** - Hormone replacement therapy: Estrogen for girls and testosterone for boys to induce puberty. - GnRH therapy or pulsatile GnRH for some cases to stimulate gonadal function and normal puberty progression.
433
What is the role of GnRH testing in evaluating puberty disorders?
- **Role of GnRH Testing in Puberty Disorders:** - GnRH stimulation test to assess pituitary response to GnRH, with evaluation of LH/FSH secretion. - Used to differentiate between central (hypothalamic/pituitary) vs peripheral (gonadal or other) causes of delayed puberty.
434
What are the features of 46,XX DSD with ovotesticular disorder?
- **Features of 46,XX DSD with Ovotesticular Disorder:** - Gonads have both ovarian and testicular tissue (ovotestes). - Features may include ambiguous genitalia, infertility, and variable secondary sexual characteristics. - Diagnosis: Karyotype and gonadal biopsy.
435
What is the management of ambiguous genitalia with suspected 46,XY DSD?
- **Management of Ambiguous Genitalia with 46,XY DSD:** - Multidisciplinary approach: genetic counseling, evaluation of chromosomal sex, endocrine testing, and imaging. - Gender assignment based on clinical and psychological factors, hormone therapy, and possibly surgery.
436
How is Turner syndrome diagnosed during childhood?
- **Diagnosis of Turner Syndrome in Childhood:** - Clinical features: Short stature, webbed neck, low-set ears. - Diagnosis: Karyotype analysis (45,X or mosaicism). - Confirmed by chromosome analysis and often by ultrasound (e.g., coarctation of the aorta).
437
What are the effects of ovarian failure in adolescents with Turner syndrome?
- **Effects of Ovarian Failure in Turner Syndrome Adolescents:** - Lack of spontaneous puberty (absence of menstruation). - Need for estrogen replacement therapy for pubertal induction and bone health. - Fertility is usually absent, though assisted reproductive techniques can be considered.
438
How does Klinefelter syndrome affect fertility in males?
- **Effect of Klinefelter Syndrome on Male Fertility:** - 47,XXY karyotype; males have small testes, low testosterone, and azoospermia (no sperm production). - Testosterone replacement therapy is used, but fertility is typically not achievable naturally; sperm retrieval techniques can sometimes be considered.
439
What is the diagnostic approach for precocious puberty in males?
- **Diagnostic Approach to Precocious Puberty in Males:** - Evaluation of growth and pubertal markers, including bone age radiographs and gonadotropin levels (LH, FSH). - MRI brain (especially if CNS lesion is suspected, such as hypothalamic hamartomas).
440
What is the treatment for precocious puberty due to hypothalamic hamartoma?
- **Treatment of Precocious Puberty Due to Hypothalamic Hamartoma:** - GnRH analogs (e.g., leuprolide) to suppress early puberty. - Surgery (if hamartoma is operable) or other interventions to manage the underlying cause.
441
What is the basic anatomy and function of the parathyroid glands?
- **Anatomy and Function of Parathyroid Glands:** - The parathyroid glands are typically four small glands located on the posterior surface of the thyroid gland. - Function: Secrete parathyroid hormone (PTH) to regulate calcium and phosphate levels in the blood and bone.
442
How does parathyroid hormone (PTH) regulate calcium and phosphate metabolism?
- **PTH Regulation of Calcium and Phosphate Metabolism:** - PTH increases calcium levels by promoting calcium release from bones, increasing renal reabsorption of calcium, and enhancing calcium absorption in the gut (via vitamin D activation). - It decreases phosphate levels by promoting phosphate excretion by the kidneys.
443
What are the causes of hypoparathyroidism in children?
- **Causes of Hypoparathyroidism in Children:** - Genetic causes (e.g., DiGeorge syndrome, mutations in the PTH gene). - Post-surgical (e.g., after thyroid or parathyroid surgery). - Autoimmune conditions (e.g., autoimmune polyendocrine syndrome type 1).
444
What are the clinical features of hypoparathyroidism in children?
- **Clinical Features of Hypoparathyroidism in Children:** - Symptoms due to hypocalcemia: Tetany, muscle cramps, seizures, and Chvostek's sign (twitching of facial muscles).
445
How is hypoparathyroidism diagnosed in children?
- **Diagnosis of Hypoparathyroidism in Children:** - Low serum calcium, high serum phosphate, and low PTH levels. - Genetic testing if a hereditary cause is suspected. - Urinary calcium levels may be helpful.
446
What are the causes of hyperparathyroidism in children?
- **Causes of Hyperparathyroidism in Children:** - Primary hyperparathyroidism: Parathyroid adenomas, hyperplasia, or parathyroid carcinoma. - Secondary hyperparathyroidism: Often due to chronic kidney disease leading to calcium and phosphate imbalances.
447
What are the features of parathyroid adenoma and hyperplasia?
- **Features of Parathyroid Adenoma and Hyperplasia:** - **Adenoma:** A benign tumor that results in excessive PTH secretion. - **Hyperplasia:** Enlargement of all parathyroid glands, often due to chronic hypocalcemia. - Features: Hypercalcemia, nephrolithiasis, bone pain, and osteoporosis.
448
What is the role of calcium in the body, and how is it regulated by PTH?
- **Role of Calcium in the Body and Regulation by PTH:** - Calcium is vital for muscle contraction, nerve conduction, and bone health. - PTH raises calcium levels by increasing bone resorption, renal calcium reabsorption, and activating vitamin D for intestinal absorption.
449
What are the treatment options for hypercalcemia in children?
- **Treatment Options for Hypercalcemia in Children:** - **Hydration:** IV fluids to correct dehydration and promote calcium excretion. - **Loop diuretics (e.g., furosemide):** To enhance calcium excretion. - **Bisphosphonates:** To inhibit bone resorption in severe cases. - **Surgical resection:** For parathyroid adenomas.
450
What is pseudo-hypoparathyroidism, and how is it diagnosed and managed?
- **Pseudo-hypoparathyroidism Diagnosis and Management:** - Caused by end-organ resistance to PTH, resulting in low calcium and high phosphate despite high PTH levels. - Features: Short stature, obesity, round face, and brachydactyly (shortened fingers and toes). - Management: Calcium and vitamin D supplementation.
451
What are the common causes of hypercalcemia in children?
- **Common Causes of Hypercalcemia in Children:** - Primary hyperparathyroidism (parathyroid adenoma or hyperplasia). - Malignancy (e.g., osteolytic bone lesions, paraneoplastic hypercalcemia). - Hypervitaminosis D. - Granulomatous diseases (e.g., sarcoidosis).
452
How is hyperparathyroidism diagnosed in children?
- **Diagnosis of Hyperparathyroidism in Children:** - Elevated serum calcium and parathyroid hormone (PTH) levels. - Imaging of the parathyroid glands (ultrasound, sestamibi scan, or CT/MRI). - Urinary calcium excretion can help assess the severity of hypercalcemia.
453
What is the treatment for hypocalcemia due to hypoparathyroidism in children?
- **Treatment for Hypocalcemia Due to Hypoparathyroidism:** - **Calcium supplementation:** Oral or IV calcium depending on severity. - **Vitamin D supplementation** to improve calcium absorption. - **PTH replacement therapy:** Recombinant human PTH (if available).
454
What are the features of pseudohypoparathyroidism in children?
- **Features of Pseudohypoparathyroidism:** - End-organ resistance to PTH despite elevated levels. - Features: Short stature, round face, brachydactyly, obesity, and learning difficulties. - Diagnosis: Elevated PTH and low calcium levels.
455
How is secondary hyperparathyroidism due to chronic kidney disease managed in children?
- **Management of Secondary Hyperparathyroidism due to Chronic Kidney Disease:** - **Phosphate binders** to decrease serum phosphate levels. - **Calcitriol** (active form of vitamin D) to suppress PTH secretion. - **Renal transplantation** may correct the hyperparathyroidism.
456
What is the role of vitamin D in calcium and phosphate homeostasis?
- **Role of Vitamin D in Calcium and Phosphate Homeostasis:** - Vitamin D enhances calcium and phosphate absorption from the intestines. - Activates osteoblasts for bone mineralization. - Deficiency leads to hypocalcemia and increased PTH secretion.
457
What are the clinical features of parathyroid carcinoma?
- **Clinical Features of Parathyroid Carcinoma:** - Rare, malignant tumor of the parathyroid gland. - Features: Severe hypercalcemia, neck mass, and invasive behavior into surrounding structures. - Diagnosis confirmed by histopathology following resection.
458
How does parathyroid hormone (PTH) secretion affect bone remodeling?
- **PTH Secretion and Bone Remodeling:** - PTH increases bone resorption by activating osteoclasts, releasing calcium from bones. - Chronic PTH elevation (as in hyperparathyroidism) leads to osteopenia and osteoporosis.
459
What are the laboratory findings in primary hyperparathyroidism?
- **Laboratory Findings in Primary Hyperparathyroidism:** - Elevated serum calcium and PTH levels. - Low serum phosphate. - Elevated urinary calcium (hypercalciuria).
460
What are the complications of untreated hypoparathyroidism in children?
- **Complications of Untreated Hypoparathyroidism:** - Chronic hypocalcemia can lead to tetany, seizures, and developmental delays. - Long-term complications: Cataracts, basal ganglia calcifications, and heart arrhythmias.
461
What is the basic anatomy and function of the parathyroid glands?
- **Anatomy and Function of Parathyroid Glands:** - The parathyroid glands are typically four small glands located on the posterior surface of the thyroid gland. - Function: Secrete parathyroid hormone (PTH) to regulate calcium and phosphate levels in the blood and bone.
462
How does parathyroid hormone (PTH) regulate calcium and phosphate metabolism?
- **PTH Regulation of Calcium and Phosphate Metabolism:** - PTH increases calcium levels by promoting calcium release from bones, increasing renal reabsorption of calcium, and enhancing calcium absorption in the gut (via vitamin D activation). - It decreases phosphate levels by promoting phosphate excretion by the kidneys.
463
What are the causes of hypoparathyroidism in children?
- **Causes of Hypoparathyroidism in Children:** - Genetic causes (e.g., DiGeorge syndrome, mutations in the PTH gene). - Post-surgical (e.g., after thyroid or parathyroid surgery). - Autoimmune conditions (e.g., autoimmune polyendocrine syndrome type 1).
464
What are the clinical features of hypoparathyroidism in children?
- **Clinical Features of Hypoparathyroidism in Children:** - Symptoms due to hypocalcemia: Tetany, muscle cramps, seizures, and Chvostek's sign (twitching of facial muscles).
465
How is hypoparathyroidism diagnosed in children?
- **Diagnosis of Hypoparathyroidism in Children:** - Low serum calcium, high serum phosphate, and low PTH levels. - Genetic testing if a hereditary cause is suspected. - Urinary calcium levels may be helpful.
466
What are the causes of hyperparathyroidism in children?
- **Causes of Hyperparathyroidism in Children:** - Primary hyperparathyroidism: Parathyroid adenomas, hyperplasia, or parathyroid carcinoma. - Secondary hyperparathyroidism: Often due to chronic kidney disease leading to calcium and phosphate imbalances.
467
What are the features of parathyroid adenoma and hyperplasia?
- **Features of Parathyroid Adenoma and Hyperplasia:** - **Adenoma:** A benign tumor that results in excessive PTH secretion. - **Hyperplasia:** Enlargement of all parathyroid glands, often due to chronic hypocalcemia. - Features: Hypercalcemia, nephrolithiasis, bone pain, and osteoporosis.
468
What is the role of calcium in the body, and how is it regulated by PTH?
- **Role of Calcium in the Body and Regulation by PTH:** - Calcium is vital for muscle contraction, nerve conduction, and bone health. - PTH raises calcium levels by increasing bone resorption, renal calcium reabsorption, and activating vitamin D for intestinal absorption.
469
What are the treatment options for hypercalcemia in children?
- **Treatment Options for Hypercalcemia in Children:** - **Hydration:** IV fluids to correct dehydration and promote calcium excretion. - **Loop diuretics (e.g., furosemide):** To enhance calcium excretion. - **Bisphosphonates:** To inhibit bone resorption in severe cases. - **Surgical resection:** For parathyroid adenomas.
470
What is pseudo-hypoparathyroidism, and how is it diagnosed and managed?
- **Pseudo-hypoparathyroidism Diagnosis and Management:** - Caused by end-organ resistance to PTH, resulting in low calcium and high phosphate despite high PTH levels. - Features: Short stature, obesity, round face, and brachydactyly (shortened fingers and toes). - Management: Calcium and vitamin D supplementation.
471
What are the common causes of hypercalcemia in children?
- **Common Causes of Hypercalcemia in Children:** - Primary hyperparathyroidism (parathyroid adenoma or hyperplasia). - Malignancy (e.g., osteolytic bone lesions, paraneoplastic hypercalcemia). - Hypervitaminosis D. - Granulomatous diseases (e.g., sarcoidosis).
472
How is hyperparathyroidism diagnosed in children?
- **Diagnosis of Hyperparathyroidism in Children:** - Elevated serum calcium and parathyroid hormone (PTH) levels. - Imaging of the parathyroid glands (ultrasound, sestamibi scan, or CT/MRI). - Urinary calcium excretion can help assess the severity of hypercalcemia.
473
What is the treatment for hypocalcemia due to hypoparathyroidism in children?
- **Treatment for Hypocalcemia Due to Hypoparathyroidism:** - **Calcium supplementation:** Oral or IV calcium depending on severity. - **Vitamin D supplementation** to improve calcium absorption. - **PTH replacement therapy:** Recombinant human PTH (if available).
474
What are the features of pseudohypoparathyroidism in children?
- **Features of Pseudohypoparathyroidism:** - End-organ resistance to PTH despite elevated levels. - Features: Short stature, round face, brachydactyly, obesity, and learning difficulties. - Diagnosis: Elevated PTH and low calcium levels.
475
How is secondary hyperparathyroidism due to chronic kidney disease managed in children?
- **Management of Secondary Hyperparathyroidism due to Chronic Kidney Disease:** - **Phosphate binders** to decrease serum phosphate levels. - **Calcitriol** (active form of vitamin D) to suppress PTH secretion. - **Renal transplantation** may correct the hyperparathyroidism.
476
What is the role of vitamin D in calcium and phosphate homeostasis?
- **Role of Vitamin D in Calcium and Phosphate Homeostasis:** - Vitamin D enhances calcium and phosphate absorption from the intestines. - Activates osteoblasts for bone mineralization. - Deficiency leads to hypocalcemia and increased PTH secretion.
477
What are the clinical features of parathyroid carcinoma?
- **Clinical Features of Parathyroid Carcinoma:** - Rare, malignant tumor of the parathyroid gland. - Features: Severe hypercalcemia, neck mass, and invasive behavior into surrounding structures. - Diagnosis confirmed by histopathology following resection.
478
How does parathyroid hormone (PTH) secretion affect bone remodeling?
- **PTH Secretion and Bone Remodeling:** - PTH increases bone resorption by activating osteoclasts, releasing calcium from bones. - Chronic PTH elevation (as in hyperparathyroidism) leads to osteopenia and osteoporosis.
479
What are the laboratory findings in primary hyperparathyroidism?
- **Laboratory Findings in Primary Hyperparathyroidism:** - Elevated serum calcium and PTH levels. - Low serum phosphate. - Elevated urinary calcium (hypercalciuria).
480
What are the complications of untreated hypoparathyroidism in children?
- **Complications of Untreated Hypoparathyroidism:** - Chronic hypocalcemia can lead to tetany, seizures, and developmental delays. - Long-term complications: Cataracts, basal ganglia calcifications, and heart arrhythmias.

Paediatrics (20 decks)

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