Endocrine Flashcards
(251 cards)
1
Q
What is congenital hypothyroidism?
A
A condition present at birth where the thyroid gland fails to produce sufficient thyroid hormone, critical for brain development and growth.
2
Q
What are the most common causes of congenital hypothyroidism?
A
Thyroid dysgenesis (agenesis, ectopia, hypoplasia), dyshormonogenesis (defect in hormone synthesis), maternal antithyroid drugs or TSH receptor-blocking antibodies.
3
Q
What are the typical clinical features of untreated congenital hypothyroidism in neonates?
A
Prolonged jaundice, constipation, hypotonia, macroglossia, umbilical hernia, poor feeding, hoarse cry, large fontanelles, and delayed milestones.
4
Q
What is the most reliable diagnostic test for congenital hypothyroidism?
A
Newborn screening using TSH and/or T4 measurement, confirmed by serum TSH and free T4 levels.
5
Q
What are the diagnostic criteria for congenital hypothyroidism on lab testing?
A
Elevated TSH and low free T4 levels.
6
Q
When should treatment for congenital hypothyroidism be initiated?
A
Within the first 2 weeks of life, ideally within the first 10–14 days, to prevent neurodevelopmental delay.
7
Q
What is the standard treatment for congenital hypothyroidism?
A
Oral levothyroxine at a dose of 10–15 mcg/kg/day.
8
Q
What monitoring is needed after starting treatment for congenital hypothyroidism?
A
Serum TSH and free T4 every 2 weeks until normalization, then monthly until 6 months, every 2–3 months until 3 years, and 3–6 monthly thereafter.
9
Q
What imaging studies are useful in congenital hypothyroidism?
A
Thyroid ultrasound and radionuclide (technetium-99m or iodine-123) scan to assess gland location and function.
10
Q
What is the prognosis of congenital hypothyroidism if treated early?
A
Normal neurodevelopmental outcomes if treatment begins early and is well-monitored.
11
Q
What is acquired hypothyroidism in children?
A
A condition where the thyroid gland produces insufficient thyroid hormone after the neonatal period, typically due to autoimmune thyroiditis.
12
Q
What is the most common cause of acquired hypothyroidism in children?
A
Hashimoto’s thyroiditis (chronic lymphocytic thyroiditis).
13
Q
What are the clinical features of acquired hypothyroidism in children?
A
Fatigue, weight gain, cold intolerance, constipation, dry skin, delayed puberty, bradycardia, and poor linear growth.
14
Q
What are the common physical findings in acquired hypothyroidism?
A
Goiter, delayed reflex relaxation, puffiness of the face, and short stature.
15
Q
How is acquired hypothyroidism diagnosed?
A
Elevated TSH and low free T4. Positive thyroid autoantibodies (anti-TPO and anti-thyroglobulin) suggest autoimmune etiology.
16
Q
What is the role of thyroid ultrasound in acquired hypothyroidism?
A
To assess for goiter, nodules, or structural abnormalities of the thyroid gland.
17
Q
What is the treatment for acquired hypothyroidism in children?
A
Oral levothyroxine at an initial dose of 2–4 mcg/kg/day.
18
Q
How often should thyroid function tests be monitored after starting therapy?
A
Every 6–8 weeks initially, then every 6 months once stable.
19
Q
What are potential complications of untreated acquired hypothyroidism?
A
Poor growth, intellectual impairment, delayed puberty, and myxedema.
20
Q
Can acquired hypothyroidism in children resolve spontaneously?
A
Rarely. Hashimoto’s thyroiditis often leads to permanent hypothyroidism, requiring lifelong treatment.
21
Q
What is the most common cause of hyperthyroidism in children?
A
Graves’ disease, an autoimmune disorder where TSH receptor antibodies stimulate excessive thyroid hormone production.
22
Q
What are the clinical features of pediatric hyperthyroidism?
A
Weight loss despite increased appetite, heat intolerance, palpitations, tremors, anxiety, poor concentration, and hyperactivity.
23
Q
What are physical examination findings in a child with hyperthyroidism?
A
Goiter, tachycardia, widened pulse pressure, lid lag, exophthalmos (in Graves’), and fine tremor.
24
Q
What lab findings are consistent with hyperthyroidism?
A
Low TSH, elevated free T4 and/or T3 levels.
25
What autoantibodies are associated with Graves' disease?
TSH receptor antibodies (TRAb), thyroid-stimulating immunoglobulins (TSI), and sometimes anti-TPO antibodies.
26
What imaging modality is used to confirm Graves' disease?
Thyroid scintigraphy (radioactive iodine uptake scan) showing diffuse increased uptake.
27
What are the treatment options for pediatric hyperthyroidism?
Antithyroid drugs (methimazole), beta-blockers for symptom control, radioactive iodine ablation, and thyroidectomy.
28
What is the preferred first-line treatment for most children with Graves’ disease?
Methimazole, due to its efficacy and lower risk profile compared to radioactive iodine or surgery.
29
What are potential side effects of methimazole?
Agranulocytosis, rash, hepatotoxicity, and arthralgia.
30
When is thyroidectomy indicated in pediatric hyperthyroidism?
Large goiter, suspicion of malignancy, poor medication compliance, or failure of medical therapy.
31
How common are thyroid nodules in children?
Less common than in adults, but when present, they carry a higher risk of malignancy (~20-25%).
32
What are the risk factors for thyroid cancer in children?
History of radiation exposure, family history of thyroid cancer or MEN syndrome, rapid nodule growth, and firm, fixed nodules.
33
What are the clinical features of a suspicious thyroid nodule?
Painless neck mass, hoarseness, dysphagia, cervical lymphadenopathy, or rapid growth.
34
What is the first-line imaging modality for evaluating a thyroid nodule in children?
High-resolution neck ultrasound to assess size, echogenicity, vascularity, calcifications, and lymph node involvement.
35
What features on ultrasound suggest malignancy in a thyroid nodule?
Hypoechogenicity, microcalcifications, irregular margins, taller-than-wide shape, and increased central vascularity.
36
What is the role of fine-needle aspiration (FNA) in pediatric thyroid nodules?
FNA is used for cytological evaluation of nodules >1 cm with suspicious features or any size with risk factors.
37
What is the most common type of thyroid cancer in children?
Papillary thyroid carcinoma.
38
How is papillary thyroid carcinoma in children typically managed?
Total thyroidectomy, followed by radioactive iodine therapy and lifelong thyroid hormone suppression therapy.
39
What are the indications for radioactive iodine therapy in pediatric thyroid cancer?
Residual disease, metastases, or high-risk histology after surgery.
40
What is the prognosis for pediatric thyroid cancer?
Generally excellent with high survival rates, though recurrence is more common than in adults.
41
What are the major hormones regulating calcium and phosphate metabolism?
Parathyroid hormone (PTH), vitamin D (calcitriol), and calcitonin.
42
What is the most common cause of hypocalcemia in neonates?
Early-onset: prematurity, maternal diabetes, perinatal asphyxia; Late-onset: hypoparathyroidism, DiGeorge syndrome, high phosphate intake.
43
What are the clinical signs of hypocalcemia in children?
Tetany, muscle cramps, carpopedal spasm, seizures, Chvostek and Trousseau signs.
44
What are the key laboratory findings in hypocalcemia?
Low serum calcium, high phosphate (if due to hypoparathyroidism), low or inappropriately normal PTH.
45
What is the acute treatment of symptomatic hypocalcemia?
IV calcium gluconate 10% at 0.5–1 mL/kg slowly under ECG monitoring.
46
What are common causes of hypercalcemia in pediatrics?
Hyperparathyroidism, Williams syndrome, vitamin D intoxication, malignancy, subcutaneous fat necrosis.
47
What are the symptoms of pediatric hypercalcemia?
Polyuria, polydipsia, nausea, vomiting, constipation, lethargy, muscle weakness, confusion.
48
What is the initial management of hypercalcemia in children?
Hydration with IV saline, loop diuretics (e.g., furosemide), and addressing the underlying cause.
49
What are the typical findings in rickets due to vitamin D deficiency?
Delayed closure of fontanelles, frontal bossing, rachitic rosary, bowing of legs, widened wrists and ankles.
50
How is vitamin D deficiency rickets treated?
Cholecalciferol or ergocalciferol with calcium supplementation; maintenance vitamin D after correction.
51
What is congenital adrenal hyperplasia (CAH)?
A group of autosomal recessive disorders characterized by defects in adrenal steroidogenesis, most commonly 21-hydroxylase deficiency.
52
What enzyme is most commonly deficient in CAH?
21-hydroxylase (90–95% of cases).
53
What are the types of CAH based on 21-hydroxylase deficiency?
Classic salt-wasting, classic simple virilizing, and non-classic (late-onset) forms.
54
What are the clinical features of salt-wasting CAH in neonates?
Vomiting, dehydration, hyponatremia, hyperkalemia, hypotension, and shock due to aldosterone deficiency.
55
What is the presentation of simple virilizing CAH?
Ambiguous genitalia in females, early virilization in males, without salt-wasting crisis.
56
How is non-classic CAH usually detected?
Signs of androgen excess in later childhood or adolescence: hirsutism, premature pubarche, acne, and menstrual irregularities.
57
What lab abnormalities are seen in 21-hydroxylase deficiency?
Elevated 17-hydroxyprogesterone, low cortisol, low aldosterone (in salt-wasting), high ACTH.
58
What is the confirmatory test for CAH?
ACTH stimulation test showing exaggerated increase in 17-hydroxyprogesterone.
59
What is the treatment for classic CAH?
Hydrocortisone (glucocorticoid), fludrocortisone (mineralocorticoid), and sodium supplementation in infancy.
60
What are long-term considerations in CAH management?
Growth monitoring, bone age assessment, pubertal progression, fertility counseling, and stress-dose steroid education.
61
What is adrenal insufficiency?
A condition where the adrenal glands do not produce enough cortisol, and sometimes aldosterone.
62
What are the primary types of adrenal insufficiency?
Primary (Addison's disease), secondary (pituitary ACTH deficiency), and tertiary (hypothalamic CRH deficiency).
63
What are the causes of primary adrenal insufficiency in children?
Autoimmune adrenalitis, congenital adrenal hyperplasia, infections (TB, fungal), adrenal hemorrhage, or genetic syndromes (e.g., Allgrove).
64
What are the symptoms of adrenal insufficiency in children?
Fatigue, weight loss, abdominal pain, vomiting, hypotension, hyperpigmentation, salt craving, and hypoglycemia.
65
What are lab findings in primary adrenal insufficiency?
Low cortisol, high ACTH, low sodium, high potassium, and metabolic acidosis.
66
How is adrenal insufficiency diagnosed?
Low morning serum cortisol and elevated ACTH; confirmed with ACTH stimulation test (short Synacthen test).
67
How does adrenal crisis present in children?
Severe hypotension, shock, vomiting, hypoglycemia, dehydration, and altered mental status.
68
What is the emergency treatment for adrenal crisis?
IV hydrocortisone, rapid fluid resuscitation with normal saline, and correction of hypoglycemia and electrolytes.
69
What is the long-term management of adrenal insufficiency?
Hydrocortisone replacement (10–12 mg/m²/day), fludrocortisone for aldosterone deficiency, and stress dosing during illness or surgery.
70
What education is crucial for families of children with adrenal insufficiency?
Emergency steroid use, stress dosing, wearing medical alert ID, and carrying injectable hydrocortisone.
71
What defines precocious puberty in children?
Onset of secondary sexual characteristics before age 8 in girls and before age 9 in boys.
72
What are the types of precocious puberty?
Central (gonadotropin-dependent) and peripheral (gonadotropin-independent) precocious puberty.
73
What are common causes of central precocious puberty?
Idiopathic (especially in girls), CNS tumors (e.g., hypothalamic hamartoma), CNS infections, trauma, or radiation.
74
What are causes of peripheral precocious puberty?
Congenital adrenal hyperplasia, adrenal or gonadal tumors, McCune-Albright syndrome, exogenous sex steroids.
75
What are initial investigations in a child with suspected precocious puberty?
Bone age, LH/FSH levels (basal and after GnRH stimulation), estradiol/testosterone levels, and brain MRI if central origin is suspected.
76
What is the treatment of central precocious puberty?
GnRH analogs (e.g., leuprolide) to suppress premature activation of the hypothalamic-pituitary-gonadal axis.
77
What is delayed puberty?
No breast development by age 13 or no menarche by 15 in girls; no testicular enlargement by age 14 in boys.
78
What are common causes of delayed puberty?
Constitutional delay, hypogonadotropic hypogonadism (e.g., Kallmann syndrome), hypergonadotropic hypogonadism (e.g., Turner or Klinefelter syndrome).
79
How is delayed puberty evaluated?
Bone age, LH/FSH, estradiol/testosterone levels, karyotype, and MRI of brain if central cause is suspected.
80
What is the treatment for delayed puberty?
Depends on cause: sex steroid replacement (e.g., estrogen or testosterone) for induction, and treatment of underlying cause.
81
What are the main categories of growth disorders in children?
Familial short stature, constitutional growth delay, and pathological causes (endocrine, systemic, genetic).
82
What defines short stature?
Height below the 3rd percentile or more than 2 standard deviations below the mean for age and sex.
83
What are key features of familial short stature?
Normal birth weight/length, normal growth velocity, bone age equal to chronological age, and family history of short stature.
84
What are features of constitutional growth delay?
Delayed growth in childhood with delayed puberty and bone age, but eventual normal adult height.
85
What are endocrine causes of short stature?
Growth hormone deficiency, hypothyroidism, Cushing’s syndrome, and poorly controlled diabetes.
86
What systemic diseases can lead to growth failure?
Chronic renal disease, inflammatory bowel disease, congenital heart disease, and malnutrition.
87
What are genetic causes of short stature?
Turner syndrome, Noonan syndrome, Prader-Willi syndrome, SHOX gene mutations.
88
How is growth hormone deficiency diagnosed?
Growth failure, low IGF-1/IGFBP-3, poor GH response on stimulation tests (e.g., insulin tolerance test).
89
What is the treatment for growth hormone deficiency?
Daily subcutaneous recombinant human growth hormone (rhGH) injections.
90
How is bone age assessed and interpreted in growth disorders?
Via X-ray of left hand/wrist; delayed in constitutional delay, normal in familial short stature, variable in pathological causes.
91
What are the main types of diabetes mellitus in children?
Type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM), and monogenic diabetes (e.g., MODY, neonatal diabetes).
92
What is the most common type of diabetes in children?
Type 1 diabetes mellitus.
93
What is the pathophysiology of type 1 diabetes mellitus?
Autoimmune destruction of pancreatic beta cells leading to absolute insulin deficiency.
94
What are the typical symptoms of type 1 diabetes?
Polyuria, polydipsia, weight loss, fatigue, and sometimes diabetic ketoacidosis (DKA).
95
What tests are used to diagnose diabetes in children?
Fasting glucose ≥126 mg/dL, 2-hour OGTT glucose ≥200 mg/dL, HbA1c ≥6.5%, or random glucose ≥200 mg/dL with symptoms.
96
What antibodies are commonly positive in T1DM?
GAD, IA-2, insulin autoantibodies, and ZnT8 antibodies.
97
How is T1DM managed in children?
Basal-bolus insulin regimen or insulin pump, glucose monitoring, carb counting, and diabetes education.
98
What are acute complications of diabetes in children?
Hypoglycemia, hyperglycemia, and diabetic ketoacidosis (DKA).
99
What is diabetic ketoacidosis (DKA)?
A life-threatening complication of T1DM with hyperglycemia, ketosis, and metabolic acidosis.
100
What is the treatment of DKA?
Fluid resuscitation, insulin infusion, correction of electrolytes (especially potassium), and close monitoring.
101
What defines obesity in children?
BMI ≥95th percentile for age and sex based on CDC or WHO growth charts.
102
What defines overweight in children?
BMI between the 85th and 94th percentile for age and sex.
103
What are the major causes of obesity in children?
Excess caloric intake, sedentary lifestyle, genetic predisposition, endocrine disorders (rare), and some medications.
104
What are common complications of pediatric obesity?
Type 2 diabetes, dyslipidemia, hypertension, fatty liver disease, sleep apnea, and orthopedic issues.
105
What is metabolic syndrome in children?
A cluster of conditions including central obesity, insulin resistance, hypertension, dyslipidemia, and impaired glucose tolerance.
106
How is metabolic syndrome diagnosed in pediatrics?
Using modified adult criteria: elevated waist circumference, triglycerides, low HDL, hypertension, and high fasting glucose.
107
What lab tests are recommended for obese children?
Fasting glucose, lipid panel, liver function tests, HbA1c, and sometimes insulin and thyroid function tests.
108
What is the first-line treatment for pediatric obesity?
Lifestyle modification including dietary changes, increased physical activity, behavior therapy, and family involvement.
109
When is pharmacologic treatment considered for pediatric obesity?
In adolescents with BMI ≥95th percentile and comorbidities after failed lifestyle interventions.
110
What are the medications approved for obesity in adolescents?
Orlistat and liraglutide (for select cases); metformin is used off-label for insulin resistance or T2DM.
111
What is hypoglycemia in neonates?
Plasma glucose <45 mg/dL (2.5 mmol/L) in symptomatic or high-risk neonates.
112
What are common causes of neonatal hypoglycemia?
Hyperinsulinism (e.g., infants of diabetic mothers), intrauterine growth restriction, prematurity, perinatal stress, metabolic disorders.
113
What is the Whipple’s triad for hypoglycemia?
Symptoms of hypoglycemia, low plasma glucose, and resolution of symptoms after glucose normalization.
114
What are the symptoms of hypoglycemia in infants and children?
Jitteriness, lethargy, seizures, poor feeding, sweating, pallor, irritability, and coma.
115
What endocrine disorders can cause hypoglycemia?
Adrenal insufficiency, growth hormone deficiency, congenital hyperinsulinism.
116
What metabolic disorders are associated with hypoglycemia?
Glycogen storage diseases, fatty acid oxidation disorders, organic acidemias.
117
What initial labs should be obtained during hypoglycemia?
Glucose, insulin, C-peptide, beta-hydroxybutyrate, cortisol, growth hormone, lactate, ammonia, and free fatty acids.
118
What is congenital hyperinsulinism?
A condition with unregulated insulin secretion causing persistent hypoglycemia in neonates and infants.
119
What is the treatment for hypoglycemia due to hyperinsulinism?
Diazoxide, frequent feeds, dextrose infusion, or surgery (e.g., pancreatectomy) in resistant cases.
120
What is the emergency treatment for symptomatic hypoglycemia?
IV dextrose 10% (D10W) at 2 mL/kg bolus, followed by continuous infusion, or glucagon IM if no IV access.
121
What is McCune-Albright syndrome?
A genetic disorder caused by GNAS mutation characterized by precocious puberty, café-au-lait spots, and fibrous dysplasia of bone.
122
What endocrine abnormalities are seen in McCune-Albright syndrome?
Gonadotropin-independent precocious puberty, hyperthyroidism, growth hormone excess, and Cushing syndrome.
123
What is Prader-Willi syndrome?
A genetic disorder due to paternal deletion on chromosome 15q11-q13 characterized by hypotonia, hyperphagia, obesity, and hypogonadism.
124
What are the endocrine issues in Prader-Willi syndrome?
Growth hormone deficiency, hypogonadism, central adrenal insufficiency, and hypothyroidism.
125
What is Beckwith-Wiedemann syndrome?
An overgrowth syndrome with features like macrosomia, macroglossia, organomegaly, hemihypertrophy, and increased tumor risk (e.g., Wilms tumor).
126
What endocrine features are associated with Beckwith-Wiedemann syndrome?
Neonatal hypoglycemia due to hyperinsulinism, increased IGF-2 expression, and risk of adrenal tumors.
127
What is Turner syndrome?
A chromosomal disorder (45,X) in females characterized by short stature, gonadal dysgenesis, and various congenital anomalies.
128
What endocrine problems are seen in Turner syndrome?
Primary ovarian failure, hypothyroidism (Hashimoto), and growth hormone deficiency.
129
What is Klinefelter syndrome?
A chromosomal disorder in males (47,XXY) with tall stature, small testes, gynecomastia, and infertility.
130
What endocrine issue is most common in Klinefelter syndrome?
Hypergonadotropic hypogonadism with low testosterone and high LH/FSH.
131
What are the main functions of the anterior pituitary?
Secretion of ACTH, TSH, GH, LH, FSH, and prolactin.
132
What are causes of hypopituitarism in children?
Congenital (e.g., septo-optic dysplasia), tumors (e.g., craniopharyngioma), trauma, infection, irradiation, and genetic mutations.
133
What are the features of panhypopituitarism?
Deficiency of multiple pituitary hormones causing growth failure, adrenal insufficiency, hypothyroidism, delayed puberty, and hypoglycemia.
134
What are the signs of growth hormone deficiency?
Short stature, delayed bone age, increased fat mass, and poor linear growth with normal head circumference.
135
What test is used to diagnose growth hormone deficiency?
GH stimulation tests (e.g., insulin tolerance test, arginine, clonidine); low IGF-1 and IGFBP-3 levels.
136
What are the clinical features of prolactinoma in children?
Headache, visual disturbances, galactorrhea, delayed puberty, and hypogonadism.
137
How is a pituitary adenoma diagnosed?
MRI of the pituitary with hormonal evaluation (e.g., prolactin, IGF-1, cortisol, TSH, LH/FSH).
138
What is the treatment of prolactinoma in pediatrics?
Dopamine agonists such as cabergoline or bromocriptine; surgery if resistant or compressive symptoms.
139
What is central diabetes insipidus (DI)?
Deficiency of ADH (vasopressin) causing polyuria, polydipsia, and hypernatremia.
140
How is central DI diagnosed and treated?
Water deprivation test followed by desmopressin (DDAVP) response; treatment with intranasal or oral DDAVP.
141
What are common endocrine causes of pediatric hypertension?
Primary hyperaldosteronism, Cushing syndrome, pheochromocytoma, congenital adrenal hyperplasia (CAH), and hyperthyroidism.
142
What is primary hyperaldosteronism?
Excess aldosterone production causing hypertension, hypokalemia, metabolic alkalosis, and low renin levels.
143
How is primary hyperaldosteronism diagnosed?
Elevated aldosterone-to-renin ratio (ARR), confirmed with saline suppression or fludrocortisone suppression test.
144
What are the features of Cushing syndrome in children?
Weight gain, growth failure, moon face, central obesity, hirsutism, purple striae, and hypertension.
145
What tests are used to diagnose Cushing syndrome?
Low-dose dexamethasone suppression test, late-night salivary cortisol, 24-hour urinary free cortisol.
146
What is pheochromocytoma?
A catecholamine-secreting tumor from adrenal medulla or sympathetic ganglia causing episodic hypertension, headache, sweating, and palpitations.
147
How is pheochromocytoma diagnosed?
Elevated plasma or 24-hour urinary metanephrines and catecholamines; confirmed with imaging (MRI or MIBG scan).
148
What is the treatment of pheochromocytoma?
Alpha-adrenergic blockade (phenoxybenzamine) followed by beta-blockade and surgical excision.
149
How does hyperthyroidism cause hypertension?
Increased cardiac output and sensitivity to catecholamines elevate systolic blood pressure.
150
What is Liddle syndrome?
A rare genetic disorder causing pseudohyperaldosteronism due to increased sodium reabsorption, leading to hypertension and hypokalemia.
151
What are common pediatric endocrine tumors?
Pheochromocytoma, paraganglioma, pituitary adenoma, thyroid carcinoma, and adrenocortical tumors.
152
What is the most common endocrine tumor in children?
Papillary thyroid carcinoma.
153
What is a pheochromocytoma?
A catecholamine-secreting tumor of the adrenal medulla presenting with hypertension, headache, sweating, and palpitations.
154
How is a paraganglioma different from pheochromocytoma?
Paragangliomas are extra-adrenal catecholamine-secreting tumors of the sympathetic or parasympathetic ganglia.
155
What genetic syndromes are associated with pheochromocytoma and paraganglioma?
MEN 2A/2B, VHL syndrome, NF1, and SDH gene mutations.
156
What are features of pituitary adenomas in children?
Symptoms depend on hormone produced: GH (gigantism), prolactin (galactorrhea, amenorrhea), ACTH (Cushing's disease).
157
What is the most common functional pituitary adenoma in children?
Prolactinoma.
158
How are adrenocortical tumors classified?
Benign adenomas or malignant carcinomas, may produce excess cortisol, androgens, or aldosterone.
159
What syndromes are associated with adrenocortical tumors in children?
Beckwith-Wiedemann syndrome and Li-Fraumeni syndrome.
160
How are endocrine tumors evaluated in children?
Clinical symptoms, hormonal assays, imaging (MRI/CT), and genetic testing when syndromic associations are suspected.
161
What defines short stature in pediatrics?
Height more than 2 standard deviations below the mean or below the 3rd percentile for age and sex.
162
What are the physiological (non-pathologic) causes of short stature?
Familial short stature and constitutional growth delay.
163
What is familial short stature?
A growth pattern in which the child has short parents, normal growth velocity, and bone age consistent with chronological age.
164
What is constitutional growth delay?
A delay in growth and puberty with eventual attainment of normal adult height; associated with delayed bone age.
165
What are pathological causes of short stature?
Endocrine disorders (e.g., GH deficiency, hypothyroidism), chronic diseases (e.g., IBD, renal failure), genetic syndromes (e.g., Turner syndrome), and skeletal dysplasias.
166
What are red flags in the evaluation of short stature?
Decreasing height velocity, crossing percentiles downward, dysmorphic features, or chronic systemic symptoms.
167
What initial investigations should be done for a child with short stature?
Bone age X-ray, CBC, ESR, renal and liver function tests, TSH, free T4, IGF-1, IGFBP-3, celiac screen, and karyotype in girls.
168
What is the role of bone age in evaluating short stature?
Helps differentiate between constitutional delay (delayed bone age), familial short stature (normal bone age), and pathological causes.
169
What conditions are associated with disproportionate short stature?
Skeletal dysplasias such as achondroplasia.
170
When is growth hormone therapy indicated in short stature?
In confirmed GH deficiency, Turner syndrome, chronic renal insufficiency, Prader-Willi syndrome, and idiopathic short stature with poor predicted adult height.
171
What defines tall stature in children?
Height greater than 2 standard deviations above the mean or above the 97th percentile for age and sex.
172
What are common physiological causes of tall stature?
Familial tall stature and constitutional advancement of growth.
173
What are common pathological causes of tall stature?
Endocrine causes (e.g., hyperthyroidism, GH excess), genetic syndromes (e.g., Marfan, Sotos, Klinefelter), and cerebral gigantism.
174
What are features of Marfan syndrome?
Tall stature, long limbs, arachnodactyly, joint hypermobility, lens dislocation, and aortic root dilation.
175
What are features of Klinefelter syndrome?
Tall stature, small testes, gynecomastia, infertility, and learning difficulties in males with 47,XXY karyotype.
176
What is Sotos syndrome (cerebral gigantism)?
A genetic condition causing rapid growth in early childhood, macrocephaly, developmental delay, and advanced bone age.
177
What are the clinical features of growth hormone excess in children?
Gigantism with rapid linear growth, coarse facial features, enlarged hands and feet, and sometimes visual disturbances.
178
How is growth hormone excess diagnosed?
Elevated IGF-1 levels and failure to suppress GH during oral glucose tolerance test (OGTT).
179
What imaging is needed in suspected GH excess?
MRI of the pituitary to evaluate for adenoma.
180
What is the treatment for GH excess in children?
Surgical resection of pituitary adenoma, medical therapy (e.g., somatostatin analogs), and radiation if necessary.
181
What are the main disorders related to growth hormone (GH)?
GH deficiency, GH insensitivity (Laron syndrome), and GH excess (gigantism in children).
182
What is growth hormone deficiency (GHD)?
A condition where the pituitary fails to produce sufficient GH, leading to growth failure and short stature.
183
What are causes of GH deficiency?
Congenital (e.g., pituitary aplasia, genetic mutations) or acquired (e.g., tumors, trauma, infections, radiation).
184
What are the clinical features of GH deficiency?
Proportionate short stature, delayed bone age, increased fat mass, immature facies, and normal head circumference.
185
How is GH deficiency diagnosed?
Low IGF-1 and IGFBP-3 levels; confirmed with GH stimulation tests (e.g., insulin, arginine, clonidine).
186
What is the treatment for GH deficiency?
Daily subcutaneous injections of recombinant human growth hormone (rhGH).
187
What is Laron syndrome?
A rare autosomal recessive disorder with GH receptor insensitivity, characterized by short stature despite high GH levels and low IGF-1.
188
How is Laron syndrome diagnosed?
High GH levels with low IGF-1 and poor response to GH stimulation; genetic testing confirms diagnosis.
189
What is the treatment for Laron syndrome?
Recombinant IGF-1 therapy (mecasermin).
190
What is gigantism?
Excessive GH secretion before epiphyseal closure, leading to abnormally rapid linear growth.
191
What defines delayed puberty in girls and boys?
Girls: no breast development by age 13 or no menarche by 15; Boys: no testicular enlargement by age 14.
192
What are the two main types of delayed puberty?
Hypogonadotropic hypogonadism (low LH/FSH) and hypergonadotropic hypogonadism (high LH/FSH).
193
What are causes of hypogonadotropic hypogonadism?
Constitutional delay, pituitary tumors, Kallmann syndrome, functional suppression due to chronic illness or malnutrition.
194
What are causes of hypergonadotropic hypogonadism?
Turner syndrome in girls, Klinefelter syndrome in boys, gonadal dysgenesis, or chemotherapy/radiation damage.
195
What initial investigations are used for delayed puberty?
Bone age, LH/FSH, estradiol/testosterone levels, TSH, prolactin, and sometimes MRI of the brain.
196
What is the treatment for delayed puberty?
Depends on the cause; sex steroid therapy (estrogen or testosterone) for induction and maintenance of puberty.
197
What defines precocious puberty?
Onset of secondary sexual characteristics before age 8 in girls and before age 9 in boys.
198
What is the difference between central and peripheral precocious puberty?
Central (true): GnRH-dependent; Peripheral (pseudo): GnRH-independent hormone production.
199
What are causes of central precocious puberty?
Idiopathic (especially in girls), CNS tumors, hydrocephalus, trauma, or infections.
200
What are causes of peripheral precocious puberty?
Congenital adrenal hyperplasia, adrenal/gonadal tumors, McCune-Albright syndrome, exogenous sex hormones.
201
What is the most common enzyme deficiency in CAH?
21-hydroxylase deficiency (21-OH) is the most common, accounting for over 90% of cases.
202
What are the key features of 21-hydroxylase deficiency?
Salt-wasting, hypotension, dehydration, virilization in females, and elevated 17-OHP levels.
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Why does 21-OH deficiency cause virilization?
Cortisol and aldosterone synthesis is blocked, leading to shunting of precursors to androgen synthesis.
204
What distinguishes 11β-hydroxylase deficiency from 21-OH deficiency?
11β-OH deficiency causes hypertension due to excess DOC (a mineralocorticoid), along with virilization.
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Why does 11β-OH deficiency cause hypertension?
Accumulation of deoxycorticosterone (DOC), which has mineralocorticoid activity, raises blood pressure.
206
What are the hallmark features of 17α-hydroxylase deficiency?
Hypertension and undervirilization due to decreased cortisol and sex steroids, with increased mineralocorticoid effect.
207
What is the hormonal profile in 17α-hydroxylase deficiency?
↓Cortisol, ↓sex steroids, ↑aldosterone precursors → HTN + sexual infantilism or under-virilization.
208
What is the clinical presentation of 3β-HSD deficiency?
Ambiguous genitalia in both sexes, salt-wasting crisis, and deficiency of all adrenal steroids.
209
What is the biochemical defect in 3β-HSD deficiency?
Impaired synthesis of all major steroid hormones (glucocorticoids, mineralocorticoids, and androgens).
210
What is StAR defect and how does it present?
Steroidogenic Acute Regulatory (StAR) protein defect causes lipoid CAH, presenting as early severe adrenal failure with no steroid production.
211
Nutritional (Vit D deficiency)
Low dietary intake or sun exposure
212
Vit D-dependent type I
1α-hydroxylase deficiency (AR)
213
Vit D-dependent type II
VDR mutation (AR)
214
X-linked hypophosphatemic rickets
PHEX mutation → renal phosphate wasting
215
Fanconi syndrome (Renal rickets)
Proximal tubular dysfunction
216
Hypophosphatasia
ALP gene mutation → defective mineralization
217
What are common causes of neonatal hypocalcemia?
Early onset: prematurity, maternal diabetes, birth asphyxia; Late onset: DiGeorge syndrome, hypoparathyroidism, high phosphate intake.
218
How does childhood hypocalcemia differ from neonatal?
More often due to vitamin D deficiency, hypoparathyroidism, or pseudohypoparathyroidism.
219
What is the difference between primary, secondary, and tertiary hyperparathyroidism?
Primary: ↑PTH, ↑Ca; Secondary: ↑PTH, ↓Ca (e.g., CKD); Tertiary: autonomous ↑PTH after chronic secondary hyperPTH.
220
How do central and nephrogenic diabetes insipidus differ?
Central: ↓ADH production; Nephrogenic: renal resistance to ADH. Central responds to DDAVP, nephrogenic does not.
221
What distinguishes SIADH from cerebral salt wasting (CSW)?
SIADH: euvolemic hyponatremia; CSW: hypovolemic hyponatremia with natriuresis.
222
What are the features of Hashimoto thyroiditis?
Chronic autoimmune thyroiditis with goiter, positive TPO antibodies, hypothyroidism.
223
What are features of subacute (De Quervain) thyroiditis?
Painful thyroid, post-viral, transient hyperthyroidism, elevated ESR, low uptake on scan.
224
How do Graves disease and Hashimoto thyroiditis differ?
Graves: hyperthyroidism, TSI antibodies, high uptake; Hashimoto: hypothyroidism, TPO/anti-Tg antibodies.
225
How does primary adrenal insufficiency differ from secondary?
Primary: ↓cortisol, ↑ACTH, hyperpigmentation, hyperkalemia; Secondary: ↓cortisol, ↓ACTH, no hyperkalemia.
226
How does pseudohypoparathyroidism differ from true hypoparathyroidism?
Both have ↓Ca, ↑PO4, but pseudohypo has ↑PTH (resistance), while hypoparathyroidism has ↓PTH.
227
Compare types of Congenital Adrenal Hyperplasia (CAH): 21-OH, 11β-OH, 17α-OH, 3β-HSD, and StAR defect.
Mnemonic: '21, 11, 17, 3, Star'. 21-OH: salt-wasting + virilization; 11β-OH: HTN + virilization; 17α-OH: HTN + undervirilization; 3β-HSD: ambiguous genitalia + salt-wasting; StAR defect: severe adrenal failure in infancy.
228
Differentiate nutritional rickets from X-linked hypophosphatemic rickets and vitamin D–dependent rickets.
Nutritional: ↓Ca, ↓P, ↑ALP, ↑PTH, ↓Vit D; XLH: ↓P, normal Ca, normal Vit D, ↑ALP; Vit D–dependent I: ↓Ca, ↓P, ↑PTH, ↑Vit D precursors.
229
Compare hypoparathyroidism and pseudohypoparathyroidism.
Both cause hypocalcemia and hyperphosphatemia; hypoPTH = low PTH, pseudo = high PTH but resistance.
230
Compare primary, secondary, and tertiary hyperparathyroidism.
Primary: ↑Ca, ↓P, ↑PTH; Secondary (renal failure): ↓Ca, ↑P, ↑PTH; Tertiary: ↑Ca, ↑P, very high PTH.
231
What is neonatal diabetes mellitus (NDM)?
A rare form of diabetes presenting within the first 6 months of life due to insufficient insulin secretion.
232
How is neonatal diabetes mellitus classified?
It is classified into Transient Neonatal Diabetes Mellitus (TNDM) and Permanent Neonatal Diabetes Mellitus (PNDM).
233
What is the genetic cause of most cases of Transient Neonatal Diabetes Mellitus (TNDM)?
6q24 imprinting abnormalities including paternal uniparental disomy, duplication, or methylation defects.
234
What are common gene mutations in Permanent Neonatal Diabetes Mellitus (PNDM)?
KCNJ11, ABCC8, INS, EIF2AK3.
235
What is the typical clinical presentation of NDM?
Poor feeding, polyuria, dehydration, failure to thrive, and low birth weight.
236
How is NDM differentiated from Type 1 Diabetes Mellitus?
NDM presents before 6 months of age and has negative diabetes autoantibodies.
237
What is the treatment of choice in KATP channel mutations (KCNJ11, ABCC8)?
Oral sulfonylureas such as glibenclamide.
238
When is insulin therapy used in neonatal diabetes?
In patients without KATP mutations or during initial management of hyperglycemia/DKA.
239
What syndrome is associated with EIF2AK3 mutation and NDM?
Wolcott-Rallison syndrome.
240
What is the prognosis of Transient Neonatal Diabetes Mellitus?
It resolves by 18 months but may relapse later in life.
241
What is the most common cause of pediatric obesity?
Exogenous obesity due to excessive calorie intake and reduced physical activity.
242
How can exogenous obesity be distinguished from endocrine causes?
Exogenous obesity typically has normal height velocity; endocrine causes show poor linear growth.
243
What are common endocrine causes of pediatric obesity?
Hypothyroidism, Cushing syndrome, growth hormone deficiency, pseudohypoparathyroidism.
244
What is the clinical clue to hypothyroidism in an obese child?
Weight gain with poor linear growth, fatigue, constipation, and cold intolerance.
245
What features suggest Cushing syndrome as a cause of obesity?
Truncal obesity, moon face, buffalo hump, hypertension, and striae with poor height velocity.
246
What syndromic conditions are associated with pediatric obesity?
Prader-Willi syndrome, Bardet-Biedl syndrome, Alström syndrome.
247
How is Prader-Willi syndrome clinically recognized?
Neonatal hypotonia, poor feeding in infancy, followed by hyperphagia, obesity, short stature, and intellectual disability.
248
What is the typical BMI percentile cutoff for pediatric obesity?
BMI ≥95th percentile for age and sex.
249
What lab evaluation is done in an obese child with suspected endocrine cause?
TSH, free T4, cortisol levels, IGF-1, and bone age assessment.
250
How is exogenous obesity managed in pediatrics?
Dietary modification, increased physical activity, behavioral therapy, and family involvement.
251
What is Tanner Staging?
The Tanner staging system is a 5-stage scale used to assess pubertal development based on secondary
sexual characteristics.
Girls
Breast Development (B1-B5):
- B1: Prepubertal
- B2: Breast bud
- B3: Further enlargement
- B4: Areola forms secondary mound
- B5: Mature breast
Pubic Hair (PH1-PH5):
- PH1: None
- PH2: Sparse, straight
- PH3: Dark, coarse, curly
- PH4: Adult type, limited area
- PH5: Adult, spread to thighs
Boys
Genital Development (G1-G5) with Testicular Volume:
- G1: Prepubertal; testicular volume < 4 mL
- G2: Scrotal/testicular enlargement; 4-8 mL
- G3: Penis lengthens; 9-12 mL
- G4: Penis thickens; 12-15 mL
- G5: Adult genitalia; >15-20 mL
Pubic Hair (PH1-PH5):
- Same as in girls
