Flashcards in Endocrinology Deck (393):
What is responsible for the formation of male external genitals?
Presence of androgens
What results in the regression of female internal duct structures?
Presence of mullerian inhibiting factor
What is the default pattern of differentiation of the genital system?
Towards phenotypic "femaleness"...unless the system is dominated by the influence of androgens and mullerian inhibiting factor
What is the sequence of male pubertal development?
Testicular growth - Pubarche - Penile growth - Peak height velocity
What is the first sign of pubertal development in males?
What defines testicular enlargement?
Testicular length greater than 2.5cm... indicates the onset of puberty
When do boys typically being puberty (testicular enlargement)?
What is typically done for gynecomastia in a male or asymmetric breasts in a female?
Nothing... this is normal and you usually just need to reassure them
What condition presents with gynecomastia that you need to watch out for other signs/symptoms?
What 2 situations with breast development should be considered an abnormal finding?
History of exposure to ketoconazole or bilateral gynecomastia in males
What street drug can cause galactorrhea?
What suggests androgen stimulation from outside the gonadal area in a male?
Pubic hair development and penis enlargement in the absence of testicular enlargement
What is the sequence of female pubertal development?
Breast budding - Pubarche - Peak Height Velocity - Menarche
When can females begin puberty?
As young as age 8... prior to this is considered abnormal
When is puberty defined as delayed?
If there are no pubertal signs by age 14 in boys and no breast development by age 13 in girls
What is the most likely cause of delayed puberty in boys?
Constitutional delay of puberty
What is your clue that delayed puberty is benign?
The growth curve they will show you for delayed puberty is likely to look exactly like the one for constitutional delay of growth...if growth curve is abnormal, then consider other conditions as the cause for the delay.
With constitutional delay of puberty, what is the typical bone age?
Typically 2 or more years delayed
What are 3 common/important things to consider with delayed puberty in girls?
1. Constitutional delay of puberty
2. Functional gonadotropin deficiency (anorexia nervosa)
3. Primary ovarian failure (Turner Syndrome)
True or False: Delayed puberty has various psychosocial effects on teens (boys more than girls).
True...many feel inadequate and report that their lack of development has affected their success either at work, at school, or socially.
Should kids with delayed puberty be evaluated by endocrinology?
How are boys with delayed puberty treated?
Monthly IM injections of testosterone
How are girls with delayed puberty treated?
Oral estrogen (higher doses required for those girls with Turner Syndrome)
What is it called when a girl has the presence of androgenic sexual characteristics (axillary hair, pubic hair, acne, and/or adult body odor) without estrogenic sexual characteristics (breast development and menarche) and without the growth spurt of puberty?
What are the 3 lab findings associated with premature adrenarche?
1. Elevated serum dehydroepiandosterone (DHEA)
2. Elevated serum dehydroepiandrosterone-sulfate (DHEA-S)
3. Low concentrations of testosterone
Does premature adrenarche require treatment?
What are 3 things that can cause adrenarche in males or females?
1. Exogenous androgen
2. Endogenous androgen-secreting tumor
3. Late-onset congenital adrenal hyperplasia
What hormone producing tumors can cause pubertal change in boys, but not girls?
Tumors producing HCG
What hormones do girls require to stimulate ovarian estrogen production?
LH and FSH
Which hormone is somewhat elevated and low in kids with premature adrenarche?
DHEA-S is somewhat elevated
Testosterone concentrations are low
What is thought to be a primary factor in the increased incidence of premature adrenarche in overweight children?
What can be an early sign of polycystic ovary syndrome in adolescent girls?
What are 2 benign conditions that don't represent true precocious (central) puberty?
1. Premature adrenarche
2. Premature thelarche
What is required with respect to bone age to be premature adrenarche or premature thelarche?
They bone age must not be advanced more than one year. If bone age is advanced, must consider other causes for symptoms
How does benign premature thelarche present?
Unilateral or bilateral breast development in the absence of other symptoms
When is benign premature thelarche usually present?
Before age 4... this is a relatively benign finding
In what % of cases does true central precocious puberty develop later on after benign premature thelarche?
Girls with benign premature thelarche have an increased risk for developing what?
Ovarian hyperandrogenism (PCOS)
What is premature thelarche?
Breast development in girls younger than 8 in the absence of other sexual characteristics
What are some causes of premature thelarche?
1. Usually benign an due to premature activation of hypothalamic-pituitary axis
2. Exogenous estrogen
3. Estrogen-producing tumor
What are some sources of exogenous sex steroids?
1. Skin preparations
2. Oral contraceptive medication exposure
3. Weight lifting steroids
4. Plant-based phytoestrogens
(Don't forget to consider an estrogen-producing tumor)
Development of secondary sexual characteristics that are accompanied by acceleration in linear growth (crossing percentiles) or advanced bone age is indicative of what?
True central puberty
At what age for boys and girls is true central puberty defined as precocious?
Before age 9 in boys
Before age 8 in girls
If true central precocious puberty is caught early enough, what is one possible treatment?
Leuprolide... this is a GnRH agonist which will arrest the progression (very expensive)
Which groups of patients is leuprolide more often recommended for?
1. Male patients
2. Younger than 6
3. Very rapidly advancing bone age
4. Psychosocial disturbances
This is decided in consultation with endocrinology
What is the only significant consequence of true precocious puberty?
Short adult height
What is the best approach to think when working up precocious puberty?
Anatomically from top to bottom
When you hear "optic fundus abnormal" or "visual field deficits", what should you think?
CNS lesion...possibly a pituitary mass
"Acne", "Facial and axillary hair", "muscle bulk"
Change in vaginal color and more prominent labia minora
What test can be done to look for an adrenal (premature appearance of pubic hair) or ovarian (premature breast development) mass?
What imaging study is helpful in drawing a comparison between bone age and chronological age?
Bone age XR
Name some causes of central precocious puberty (true precocious puberty) that can be found by MRI.
3. Arachnoid or ventricular cysts
7. CNS trauma
Which 3 lab tests help differentiate peripheral from central endocrinology disorders?
3. Adrenal steroids
What can ambiguous genitalia be confused with?
What constitutes a micropenis?
Normally-formed penis with the meatus in the right place and testes present within the scrotal sacs
*Ambiguous genitalia might not have testes present or the meatus in the proper place
Describe a patient with androgen insensitivity syndrome (used to be called testicular feminization syndrome)
Genetic male, but on the outside they are perfectly normal looking females. They have a blind-ending vagina and no uterus.
What causes androgen insensitivity syndrome?
Genetic males with end organ insensitivity to androgens which results in the inability to develop male external genitalia
True or False: True hermaphroditism (both ovarian and testicular tissue) is extremely rare
True...unlikely to be correct answer
What is a deficit in all hormones produced by the pituitary gland?
What should you think in a patient who presents with a micropenis and hypoglycemia?
If you suspect panhypopituitarism, what should you do next?
Check ALL pituitary hormones
What 3 syndromes can panhypopituitarism be a part of?
1. Prader-Willi (sick Willy)
2. Kallmann (poor sense of smell)
3. Septo-optic dysplasia
If you have a female present with inguinal masses, what should you consider?
That these could be testes and she has androgen insensitivity syndrome
Patient presents with primary amenorrhea and workup reveals no uterus or ovaries?
Androgen insensitivity syndrome
How is androgen insensitivity syndrome inherited?
Why do patients with androgen insensitivity syndrome have no uterus or ovaries?
Mullerian inhibiting factor is produced...so there is no development of ovaries or uterus (why the vagina ends in a blind pouch)
Child who is phenotypically female. Hint that kid is genetically male. Describes an X-linked disorder... what is diagnosis?
Androgen insensitivity syndrome
*Watch for signs of a genetic male and description of an X-linked disorder. Don't rule out x-linked disorders just cause they give phenotypical description of female gender.
What are 2 ways the adrenals can stop working?
1. They can stop functioning on their own (primary)
2. Shut down if not getting signal from pituitary (secondary) which is ACTH
What is the most common cause of adrenal insufficiency in infants?
Congenital adrenal hyperplasia
How and when does CAH present?
Often (but not always) in newborn period with a shocky/septic picture
What are the genital findings with CAH in males and females?
1. Males: No ambiguous genitalia, but there could be excessive scrotal pigmentation
2. Females: Ambiguous genitalia
What are some descriptions they will use for female ambiguous genitalia?
1. Ruggated labia
2. Clitoral hypertrophy
What causes the male features in CAH?
Increased androgen levels
Patient with growth delay. No medical care to date. History of hirsutism and amenorrhea. Most likely underlying condition?
CAH...can present beyond newborn period, so don't rule this out because the kid hasn't gotten medical intervention to date
*There is also a late-onset form of CAH that can be considered as a possible cause of growth delay
How is CAH inherited?
What can be due to cortisol production being blocked?
What is required to produce both aldosterone and cortisol?
21-Hydroxylase... when this is blocked, production of steroids leading up to the block is increased
What causes the virilization seen in CAH?
Increased levels of testosterone... due to 21-Hydroxylase deficiency and build up of steroids (because aldosterone and cortisol can't be produced)
What is important to note in family history if a male or female patient presents with virilization?
Family members taking prescribed testosterone gels for hypogonadism... this can be absorbed by other close contacts
Labs that imply other "salt-wasting disorders" (besides CAH), family history of early death, implication of ambiguous genitalia
CAH... don't be tricked into thinking this is CF. CF has an increased amount of sodium present in sweat, resulting in decreased serum sodium and "salt wasting". So even though CF is a salt water, it doesn't have anything to do with ambiguous genitalia
What is the most common cause of CAH?
What lab values are seen in the salt-wasting variety of CAH?
What specific hormone has high levels in 21-hydroxylase deficiency?
17-hydroxyprogesterone (this is the precursor before the deficient enzyme)
How is newborn screening for CAH done?
What should be done of the 17-hydroxyprogesterone assay for CAH is elevated?
Repeat the test
If a repeat test of the 17-hydroxyprogesterone assay for CAH is elevated, what is next?
Measure serum electrolytes and urinary sodium/potassium excretion
True or false: Prenatal screening of CAH is available via molecular genetic testing of fetal cells
Measurement of 17-hydroxyprogesterone in amniotic fluid is not the correct answer...not how prenatal screening is done anymore
How is CAH treated?
Glucocorticid....usually as hydrocortisone
If hydrocortisone is given in high enough doses, it will have a mineralocorticoid effect in addition to a glucocorticoid effect
What are the 2 main hormones secreted by the adrenal glands?
Which hormone secreted by the adrenal glands helps control the amount of salt and fluid in the body?
Which hormone secreted by the adrenal glands helps control how the body uses sugar and how it responds to stress?
What is most likely to occur in primary adrenal insufficiency because of the associated mineralocorticoid deficiency and salt loss?
True or False: Adrenal crisis is a medical emergency that may lead to shock and death if not recognized and treated promptly
Name symptoms of adrenal crisis.
Anorexia, vomiting, abdominal pain, weakness, fever, fatigue, lethargy, hypotension, confusion, coma (these are sudden and vague)
What are electrolyte abnormalities in adrenal crisis?
2. Hyponatremia ("salt-wasting")
What are the 3 steps to treating and adrenal crisis?
1. Give 20mL/kg of D5NS (with no K) IV over 1 hour
2. Add IV hydrocortisone
3. Add glucocorticoid replacement (after crisis has been treated)
What lab value can be elevated in adrenal insufficiency and what diagnosis might this trick you into thinking?
Antidiuretic hormone (ADH)... in this case the elevation can be an appropriate response
-Could fool you into choosing SIADH
Name 3 reasons the adrenals might stop working.
1. Autoimmune disease
*There are a variety of reasons
What is the message in the brain when the adrenals stop functioning?
"Pour out ACTH by the bucketful"
What causes the hyperpigmentation in primary adrenal deficiency (Addison Disease)?
Increased ACTH (elevated ACTH stimulates melanin production)
In primary adrenal deficiency (Addison Disease) you have a ton of ACTH being produced, but no aldosterone produced, which leads to what 3 lab values?
1. Salt wasting
(Fatigue and weight loss are other signs)
How are patients with adrenal insufficiency usually treated?
1. Fludrocortisone (for mineralocorticoid replacement)
2. Hydrocortisone (for glucocorticoid replacement)
What type of disease is Addison disease and what are the implications of this?
Usually autoimmune... these patients are at risk for other endocrine disorders including diabetes, ovarian failure, and hypothyroidism
Where is the problem in secondary adrenal deficiency?
The pituitary...there is no problem with the adrenal gland itself
What happens to ACTH in secondary adrenal deficiency?
It is low... the pituitary makes ACTH and the pituitary is the problem in secondary adrenal deficiency
What happens to ACTH in primary adrenal deficiency?
ACTH levels are high
True or False: In secondary adrenal deficiency, you find hyperkalemia, hyponatremia, and salt wasting?
False: Since there is normal aldosterone, there is no hyperkalemia, hyponatremia, or salt wasting
Which form of adrenal deficiency has hyperpigmentation and why?
Primary... there is no hyperpigmentation in secondary because there is no excess ACTH
How do people who abruptly stop taking adrenocorticoid or glucocorticoid medication present?
Signs of adrenal insufficiency... muscle weakness, decreased cardiac function (increased pulse and decreased BP)
Are electrolyte imbalances seen in adrenal insufficiency due to medication withdrawal?
What stimulates the pituitary to release ACTH?
What can CRH be used to distinguish between?
Pituitary disorders from hypothalamic failure in secondary adrenal deficiency
What happens in the cosyntropin stimulation test (ACTH stimulation test) if you have primary adrenal deficiency?
No rise in cortisol levels
What happens in the cosyntropin stimulation test (ACTH stimulation test) if you have secondary adrenal deficiency?
Cortisol is released during the test...the adrenals usually have normal cortisol stores
What is tested with the cosyntopin stimulation test (ACTH stimulation test)?
What morphological feature will be in the question if they are hinting at secondary adrenal deficiency (with the problem being in the pituitary)?
Midline defects... cleft lip and/or palate
Patient treated chronically for adrenal insufficiency with oral mineralocorticoid and hydrocortisone. Patient is going for surgery or has an acute febrile illness including vomiting... how do you adjust your medications?
-In context of vomiting patient or patient going for surgery, give parenteral hydrocortisone, typically hydrocortisone hemisuccinate (there is no such thing as parenteral mineralocorticoid)
*Don't pick IV/IM mineralcorticoid or oral medication variations
What is cosyntropin?
Synthetic corticotropin (ACTH 1-24)
What does Cushing syndrome refer to?
Glucocorticoid excess of any origin
What refers to the excessive production of corticotropin by the pituitary gland, which leads to excess cortisol production by the adrenal gland?
Name classic features of Cushing syndrome
Acne, purple striae, hirsutism, virilization, and buffalo hump
What does Cushing almost always lead to in children?
Increased BMI with growth arrest (gain in weight without gain in height)
Obesity due to increase caloric intake leads to what?
Gain in weight and gain in height
What is seen in bone age for children with Cushing?
Delayed bone age (children with non-Cushing obesity will have advanced bone age)
What is important to note if they present you with an obese child and ask for most likely diagnosis?
Growth arrest... if they gain weight and height, probably increased caloric intake. If it is just weight with no gain in height, think Cushing.
What is the most common cause of Cushing syndrome (in both kids and adults)?
Chronic use of topical, inhaled, or oral corticosteroids
What is treatment of Cushing syndrome caused by medication?
Stop the medication
What is Cushing syndrome in infants often caused by?
McCune Albright syndrome
Name 3 tests to confirm excess cortisol production (endogenous or exogenous)?
1. 24-hour urinary free cortisol excretion
2. Midnight sleeping plasma cortisol level
3. Dexamethasone suppression test
What test is the cold standard for confirming hypercortisolism?
24-hour urinary free cortisol excretion
Which test has the greatest sensitivity of all tests for Cushing Syndrome in children?
Midnight sleeping plasma cortisol level
In Cushing Syndrome, what should dexamethasone suppression tests lead to?
Undetectable plasma cortisol levels after dexamethason administration
What are the levels of morning corticotropin in cases of Cushing syndrome from adrenal tumors?
If you suspect Cushing syndrome from an adrenal tumor what is the next step (after you see undetectable corticotropin levels in the morning)?
Adrenal CT or MRI to try to locate the tumor
If a morning corticotropin level is elevated, what should be done next?
What is the peak growth velocity prior to puberty?
When does a slight, but significant deceleration in height growth occur?
Just before puberty
What happens to growth rate during puberty?
There is a gradual increase in growth rate
When does peak growth velocity reach its maximum?
Around SMR 3 in both boys and girls
When does peak growth occur in boys versus girls?
Occurs in boys roughly 2 years after girls
How long before menarche does peak growth velocity occur in girls?
About 1.5 years before menarche
Once females have reached menarche, they are within how many inches of their adult height?
Maturing earlier usually means what for height?
Shorter adult height
True or False: Growth hormone deficiency is a common cause of short stature on boards?
False: When you are presented with short stature, look for clues for other causes like hypothyroidism, syndromes (Hurlers, Hunters, Morquio, or Turner), chronic illness, familial short stature, or constitutional short stature
What are 2 correct scenarios for growth hormone deficiency on boards?
1. Kid with headaches and growth attenuation due to a space-occupying lesion
2. Congenital GHD
What can impact pituitary hormone secretion (including growth hormone secretion)?
Cranial irradiation...it is important to monitor for growth hormone deficiency in kids receiving cranial irradiation therapy
When and how does congenital growth hormone deficiency present?
1. Usually during infancy (around 6 months)
2. Slowed growth
What is the triad of congenital growth hormone deficiency?
3. Short stature
Name 3 clues to congenital growth hormone deficiency (besides micropenis, hypoglycemia, and short stature)?
1. Septo-optic dysplasia
2. Breech presentation
3. Prolonged jaundice
What can happen to bone age in congenital growth hormone deficiency?
It can be significantly delayed
4 year old child who was at the 50th percentile for both height and weight at birth. She is now at the 25h percentile for weight, but her height is below the 5th percentile. No family history of short stature. Physical exam is non-contributory. Cause?
Growth hormone deficiency...(could also be hypothyroidism if this was a choice)...If she went from 50% for height to less than 5%, she didn't triple her height or grow 5cm/year
-Constitutional growth delay: Parents have no history
-Inadequate nutrition: Weight at 25%
What is seen with height and weight for kids with nutrition deficiency?
Underweight and underheight (as evidence of chronic malnutrition)
What is seen with bone age in kids with nutrition deficiency?
Bone age is normal
Kid with growth delay who is otherwise asymptomatic. Most likely cause/next step to establish diagnosis?
Order an ESR...Crohn's disease can result in growth delay, which can precede GI symptoms (don't rule this out just because the kid is asymptomatic)
*If elevated ESR is included in labs, this could be the clue for this being Crohn's too
Which growth delay is noted as the classic "late bloomer"?
Constitutional growth delay
Which gender is constitutional growth delay more common in?
What is typically described in family history of someone with constitutional growth delay?
History of similar growth pattern in father and brother
What can be seen in the growth curve of a kid with constitutional growth delay?
Growth curve may show a decrease in growth rate, usually in early teen years
What are the 2 "rules" in constitutional growth delay?
1. Delayed onset of puberty
2. Bone age below chronological age )
When does increased growth velocity occur with constitutional growth delay?
Later onset of the increased growth velocity... growth rate may accelerate at around age 16
Besides height, what else lags behind with constitutional growth delay?
What is the memory aid for constitutional growth delay and bone age?
Bone age is below (younger than) chronological age...think of the gap as the "bud" for the later bloomer to blossom in the spring
What is the best way to assess for growth delay?
Compare bone age to chronological age
*Also look at family history (remember, least invasive and less exotic the answer, more likely it is to be correct)
When is a workup warranted for growth velocity that is blunted in early adolescence?
When this is preceded by poor weight gain
Name an example of a GI condition that can cause growth delay and can be distinguished from constitutional growth delay through lab studies?
15 year old male who is short for his age, low SMR. Growth velocity is normal. Father had same "problem" and received "shots". Most appropriate intervention?
Reassure and wait...this is constitutional growth delay
*If they note history of maternal delayed onset of menarche, this is associated with constitutional growth delay in boys and girls
*Father getting IM shots is diversion...this tells you nothing
What is it called when someone is just plain short?
Familial short stature/Genetic short stature
*Sometimes short kids are just kids who are from "short stock", and will grow up to be short adults
What are some indications that a short kid is just familial short stature?
1. Around or below 5th percentile for height
2. Bone age equal to chronological age
3. Growth velocity normal
4. May mention parents are short as well
Parents want to know potential height. Give parents' heights, but imply that one or both parents were malnourished growing up.
Child will likely be taller than the parents, assuming the child is receiving adequate nutrition
*Diversion is giving parents heights...don't miss factoring in parents' failure to reach their genetic potential due to malnourishment
How can you distinguish familial short stature from constitutional growth delay?
In familial short stature, bone age is equal to chronological age
Name 4 syndromes that make you short
1. Turner Syndrome
3. Premature puberty
What is an example of a syndrome that makes you short, but might not become evident until puberty?
Pedal edema, webbed neck, shield-like chest, scant breast tissue...what should be considered as part of workup?
Karyotype to rule out Turner
What syndrome should be considered in any short female?
Turner (even if they don't mention any of the phenotypic hints)
How are Turner patients often treated to help with their growth?
Name a syndrome that presents with short stature, but the short stature isn't proportionate.
Why does premature puberty cause the patient to be short?
Increased androgens result in premature closure of growth plates
Describe the height and weight of a kid with hypothyroidism.
Short and overweight (rarely described this way)
What happens with the bone age in kids with hypothyroidism?
Delayed bone age...might describe an 11 year old with height consistent with a 9 year old, and bone age of 7 year old
Name 4 clues that would be consistent with hypothyroidism.
1. Cold intolerance
3. Dry skin
4. Myxedema (relatively "hard edema" of the subcutaneous tissue)
What lab studies in addition to karyotype are appropriate in a patient suspected of having Turner syndrome?
What happens to LH and FSH in girls with Turner syndrome?
LH and FSH are expected to be elevated (due to ovarian failure)
What happens to estradiol levels in Turner syndrome?
Which test is not useful in girls in early puberty to evaluate for Turner syndrome?
Estradiol...although these would be low in Turner, estradiol assays might not provide an accurate picture in early puberty...so this would not be a useful measure in girls in this age group with suspected Turner syndrome
For a girl in early puberty, which tests are better to evaluate for Turner syndrome?
LH and FSH... not estradiol
"Fish for Turner with FSH and LH, than turn the dial of Estradiol"
Why are TSH levels warranted in evaluating for Turner syndrome?
Turner is associated with a higher risk of hypothyroidism (TSH would be elevated in primary hypothyroidism)
What would you expect TSH to be in Turner Syndrome?
Elevated (primary hypothyroidism)
If you are presented with a child who is "tall" for age and asked for the most important determinant for adult height..?
Sexual maturity rating
If you are presented with a "tall" kid, what can be used to predict adult height?
Bone age XR...this will help determine how much additional growth is left
Name 4 conditions that can cause tall stature.
1. Klinefelter syndrome
2. Marfan syndrome
3. Soto's syndrome
4. High caloric intake
True or False: A child with Klinefelter syndrome will appear physically normal at birth
True (eventually they will be tall)
What is the genomic issue with Klinefelter syndrome?
What are 3 other problems with Klinefelter syndrome besides tall stature?
1. Learning disabilities (intelligence is often normal)
2. Small testicles
What is one of the main features of Marfan Syndrome?
Cardiac defect (including aortic aneurysm)
Sudden death with tall stature?
Marfan Syndrome...these individuals are at risk for sudden death
Describe the stature of a patient with Marfan syndrome
-Disproportionately long legs and arms in comparison to trunk
-Significantly long tapering fingers...arachnodactyly (spider fingers)
Larger than normal head circumference as well as cognitive deficits...most likely presented in the context of parents who aren't tall
What is the problem with a kid who is tall, often overweight, and has normal to advanced bone age?
High caloric intake (big and fat)
What is one way to distinguish between exogenous obesity and endogenous obesity?
1. Exogenous obesity tends to be tall
2. Endogenous obesity (secondary to endocrine disorders) tend to be short
What were patients with congenital hypothyroidism previously known as?
Why is untreated hypothyroidism a rare disorder in real life (except on Boards)?
Neonatal screening thyroid tests are now performed routinely
What % of hypothyroid infants have no clinical manifestations at birth?
More than 95%...symptoms develop over time
Name some findings associated with congenital hypothyroidism.
Non-specific...poor feeding, jaundice
More specific...constipation, hypotonia, hoarse cry, large tongue (macroglossia), umbilical hernia, large anterior fontanelle
What is the most preventable cause of potential intellectual disability?
What % of hypothyroidism is sporadic and usually due to what?
85%...usually due to thyroid dysgenesis (aplasia, hypoplasia, ectopy)
What do most states use for newborn screening?
Initial total T4 followed by TSH testing when needed
What is needed for infants who fail a thyroid newborn screen?
Immediate testing of free T4 and TSH... most experts recommend starting newborns on oral levothyroxine (Synthroid) while lab results are pending
How is oral tablets of Synthroid given to babies?
They should be crushed and mixed in formula, human milk, or water... but NOT with soy formulas (reduces the absorption of T4)
What are the consequences of delayed treatment of congenital hypothyroidism?
Long-term consequences...learning disabilities, cognitive deficits, clumsiness and diminished fine motor skills. The longer the diagnosis and treatment are delayed, the lower the IQ.
If you are presented with a teenager with TSH results that are inconsistent with treatment, what is likely the correct explanation?
Which lab results are important before changing the dose of thyroxine in someone with congenital hypothyroidism?
Both free T4 and TSH
What are T4 and T3 reversibly bound to?
Thyroid binding globulin
Which form of thyroid hormone is metabolically active?
Free unbound hormone (not bound to TBG)
Under which 4 findings is a deficiency in TBG suspected?
1. Low serum total T4 concentrations (what is measured in most newborn screen assays)
2. Normal free T4
3. Clinically euthyroid patient
4. Normal TSH
How is diagnosis of thyroxine binding globulin deficiency made?
Confirmed by measuring a TBG level
How is thyroxine binding globulin deficiency treated?
Thyroid replacement isn't necessary...normal free T4 concentrations are maintained and the patients remain euthyroid
Secondary hypothyroidism can be caused by disease at which 2 levels?
Hypothalamic or pituitary
In secondary hypothyroidism, what happens to TSH and free T4?
TSH may be low or normal
Free (unbound) T4 is low
What is Hashimoto thyroiditis also known as?
Chronic lymphocytic thyroiditis
What type of disease is Hashimoto thyroiditis?
Autoimmune disease characterized by antibodies to thyroid tissue and lymphocytic infiltration
Which gender is hashimoto thyroitis more common in?
Females (as with most autoimmune conditions)
What is the most common cause of acquired childhood hypothyroidism and of goiter in adolescents?
What is the thyroid state of patients with Hashimoto thyroiditis?
Clinically euthyroid or hypothyroid
How do many cases of Hashimoto thyroiditis present?
Most are asymptomatic and discovered by the presence of a goiter
If you have a patient with a goiter who has Hashimoto thyroiditis, but is asymptomatic what needs to be checked regularly?
True or False: Some cases, patients with Hashimoto thyroiditis can develop a thyrotoxicosis known as Hashitoxicosis
True...watch for clues for Hashimoto disease in a patient who is also hyperthyroid
What should be considered if you are presented with a child who "suddenly" develops ADHD?
Hashitoxicosis....thyrotoxicosis in a patient with Hashimoto thyroiditis
Hashimoto can be a part of what polyendocrine autoimmune syndromes?
Schmidt Syndrome: Adrenal involvement, APS, or PGA type II, typically in adults
What endocrine disorder can occur with Hashimoto thyroiditis?
Type 1 DM
Hashimoto thyroiditis is common in people with what types of disorders?
Chromosomal disorders...Down syndrome, Turner syndrome, and Klinefelter syndrome
What is key for diagnosis of Hashimoto thyroiditis?
TSH (since T4 can be normal in compensated hypothyroidim)
What things should you look for in the blood to help diagnose Hashimoto thyroiditis?
2. Anti-thyroid peroxidase
Memory aid for Hashimoto thyroiditis?
-2 O's to remind you hypOthyroidism is the more typical presentation
-I to remind you that it can present with transiently high thyroid hormone
What is treatment for Hashimoto thyroiditis?
Lifelong levothyroxine replacement
How can you distinguish between hyperthyroidism in Graves and Hashimoto?
Radioactive iodine uptake...Elevated in Graves and normal or low in Hashimoto
-Presence of bulging eyes may tip you off that it is Graves, but the absence doesn't rule it out
-Can measure human thyroid stimulating immunoglobulin, but this can't be done everywhere
What is the difference for treatment of hyperthyroidism between Graves and Hashimoto?
-Antithyroid therapy is appropriate with Graves disease, but inappropriate with Hashimoto (this is usually transitory and requires only monitoring)
What is Graves disease caused by?
IgG antibody...known as thyroid-stimulating immunoglobulin (known as LATS during early 80s)
What is pathognomonic for Graves disease?
Bulging eyes (infiltrative opthalmopathy)
What might they describe for a child with Graves disease?
-Emotional lability (since kids with Graves disease tend to be "revved up"...don't be tricked into thinking this is a psychiatric diagnosis)
What are some subtle findings that can be seen in more mild Graves disease?
Increased appetite with weight loss, decreased muscle strength or endurance, decreased school performance, hyperactivity, itching, tremors, sweating, increased urination at night, decreased menstrual flow, and/or decreased frequency of menses
What is the first line drug treatment of choice for Graves disease?
How does methimazole work?
Blocks organification of iodide and so decreases thyroid hormone synthesis
Patient with emotional lability and hyperactivity, information hinting at diagnosis of Graves Disease buried in the question...
Consider a diagnosis of Graves disease in emotionally labile and disorganized kids...especially if they provide physical and other findings consistent with Graves disease...don't fall for diversion to draw you away from a diagnosis of Graves and towards a diagnosis of bipolar or ADHD by emphasizing the emotional lability or disorganization
What is neonatal thyrotoxicosis due to?
Maternal thyroid stimulating antibodies crossing the placenta
How does neonatal thyrotoxicosis present?
Irritability, tremors, and tachycardia in the immediate newborn period
Can also see failure to thrive, feeding problems, and hyperbilirubinemia
How do you distinguish between neonatal thyrotoxicosis and inborn errors of metabolism?
Neonatal thyrotoxicosis presents in immediate newborn period while inborn errors of metabolism usually do not manifest in the immediate newborn period
What are symptoms in utero of neonatal thyrotoxicosis?
Increased heart rate and a high output state
What does lab testing reveal in neonatal thyrotoxicosis?
Low TSH, High free T4
Why is an immediate post-birth thyroid level indicated in neonatal thyrotoxicosis?
Because of the risk of cardiac arrhythmias
What is the treatment for neonatal thyrotoxicosis?
Methimazole until the maternal antibodies are cleared
True or False: A solitary thyroid nodule can be a sign of thyroid cancer?
True or False: There is a greater chance of a thyroid nodule being malignant in an adult versus adolescent?
False: There is a greater chance of a nodule being malignant in an adolescent than in an adult
Is watchful waiting of a thyroid nodule an option in an adolescent?
No...even though this is an accepted practice in adults
What is the diagnostic test of choice for a thyroid nodule?
Fine needle aspiration... this can identify virtually all thyroid malignancies
When can a thyroid nodule be considered lower risk and be evaluated initially by an US?
Nodule measuring less than 1cm. with a defined border, and is soft and mobile
What is a risk factor for thyroid malignancy?
Past history of exposure to "ionizing radiation"
True or False: Exposure to "ultraviolet radiation" is a risk factor for thyroid malignancy?
When do you use a 131-iodine thyroid scan?
You don't...it is no longer felt to be useful and will be the wrong answer even though it was once used to distinguish hot from cold nodules
Name 5 situations in which you can diagnose diabetes
1. HbA1C equal to to greater than 6.5%
2. 2 Random glucose values over 200
3. 1 Random glucose value over 200 with classic symptoms of hyperglycemia
4. Fasting glucose over 126
5. 2 Hour post glucose tolerance serum glucose over 200
What is type 1 DM due to?
Islet cell destruction resulting in the inability to produce insulin
What is Type 1 DM also known as?
Insulin dependent diabetes
How does Type 1 DM present?
Classic polyuria, polydipsia, increased appetite, and weight loss
What is treatment for Type 1 DM?
Short and long acting SQ insulin...insulin pumps are also used with a baseline rate and manual override for bolus doses for meals
When is an eye exam indicated for health maintenance in type 1 DM?
Older than age 10
When do you begin monitoring lipid levels in a type 1 DM?
Starting at age 12
What is a crucial component of effective treatment of type 1 DM?
Family education regarding disease management
Patients with type 1 DM are at an increased risk for what types of diseases?
Other autoimmune diseases
Which GI condition do Type 1 DM have an increased risk for...especially in those who have onset of DM before age 10?
DKA is present if what 2 conditions are met?
1. Blood glucose level greater than 200mg/dL
2. Venous pH less than 7.30 or a bicarb level less than 15mmol/L
True or False: DKA may be seen in type 1 or type 2 DM?
What are the top 2 triggers for DKA?
1. Poor compliance
2. Intercurrent illness
Why is there a gradual reduction in the amount of insulin needed soon after the diagnosis of type 1 DM?
The last drops of insulin are being squeezed from the islet cells...this doesn't mean the diagnosis is incorrect...this is the honeymoon phase
What is the best way to check long term compliance in a diabetic?
Glycosylated hemoglobin test (hemoglobin A1C)
What is the hemoglobin A1C a reflection of?
Glucose levels over the past 3 months
Describe the progression of DKA.
1. Initially develop polyuria, polydipsia, polyphagia, and weight loss
2. This worsens until they develop nausea, emesis, and abdominal pain
3. This leads to metabolic acidosis
4. To compensate for the acidosis, they develop hyperpnea (Kussmaul respirations)
5. May progress to drowsiness and coma
What % dehydration should be assumed for DKA?
How is fluid replaced in DKA?
1. Rapid volume expansion with 10-20 cc/kg of normal saline or lactated ringers boluses over 1-2 hours
2. Rest of rehydration should be administered evenly over next 48 hours
What is the initial measured sodium in DKA?
Why is the initial measured sodium level low in DKA?
Osmotic effects of hyperglycemia leads to increased extracellular fluids... this leads to a dilutional hyponatremia
How do you calculate the corrected sodium for DKA?
Corrected NA = Measured NA + 0.3 (glucose-5.5)mmol/L
What is a sign of severe dehydration in DKA?
If the initial sodium is high
How is the sodium level managed in DKA?
It should gradually come up with rehydration
What does it mean if the measured sodium doesn't rise as the glucose falls during DKA treatment?
It can be attributed to overzealous fluid correction and this represents an increased risk for cerebral edema
What should you think if you are presented with a patient with mental status changes during DKA correction?
Concern for cerebral edema due to overzealous fluid correction
What is wrong with potassium in DKA?
There is a K deficit, regardless of the initial value they give you
How much potassium can be given when the serum potassium is low at presentation of DKA and under what circumstances?
Up to 60mEq K/L
Provided urine output is established
True or False: The dilutional hyponatremia seen in DKA is not the same as pseudohyponatremia seen in other conditions?
Describe what is causing the dilutional hyponatremia seen in DKA.
1. The hyperglycemia draws water into the intravascular compartment through osmotic pressure
2. The increased water results in the dilutional hyponatremia seen in DKA
3. Sodium levels don't go down and as hyperglycemia is corrected and hyponatremia should resolve accordingly
Why do potassium levels fall in DKA?
Variety of reasons, mainly having to do with correction of acidosis
Less K comes out of IC fluid into the EC fluid
More K is lost in urine with correction
When do you add insulin to the IV fluids when treating DKA?
After the initial 1-2 hours of fluid rehydration
When is dextrose added to IV fluids when treating DKA?
When blood glucose drops below 300
When can the insulin be changed to SQ from IV when treating DKA?
Until the acidosis has resolved (pH and bicarb normalized) and the patient is well enough to tolerate oral intake
What is considered resolved acidosis when treating DKA?
-Blood sugar no more than 300
-pH greater than 7.3
-Bicarb greater than 15
What do you need to watch for with too rapid rehydration while treating DKA?
What is the treatment for cerebral edema caused by too rapid rehydration when treating DKA?
Same as for any case of increased ICP
When is bicarb given in DKA treatment?
It should not be used in DKA because its use has been associated with cerebral edema...insulin and IV fluids are the only treatments needed to correct the acidosis
What is type 2 DM primarily due to?
What is the typical presentation of type 2 DM?
Obese child, acanthosis nigricans (dark, thickened, velvety patches of skin usually in the back of the neck or in the axillae)
What is the initial treatment of Type 2 DM?
Non-pharmacological...improved nutrition, less eating, and more exercise
What is used for type 2 DM if non-pharmacological treatment doesn't work?
Metformin (oral hypoglycemic agent)
How can type 1 and type 2 diabetes be distinguished from each other?
1. Measure autoantibodies against pancreatic beta cells (should only be present in type 1 DM)
2. Type 1 DM tends to be thin, Type 2 DM tends to be overweight
3. Type 1 DM more likely to present with classic diabetes symptoms. Type 2 DM tend to present after puberty and are much more likely to have a 1st degree relative with DM.
What are the screening criteria for Type 2 DM?
Being overweight (BMI >85% PCT) plus any 2 of following
1. Family history of Type 2 DM in 1st or 2nd degree relative
2. High risk race or ethnicity (Native American, African American, Latino, Asian American/Pacific Islander)
3. Signs of insulin resistance (acanthosis nigricans, HTN, dyslipiemia, or PCOS)
When should testing begin for Type 2 DM?
At age 10 or sooner if puberty occurs sooner
What is the preferred screening test for Type 2 DM?
Fasting plasma glucose
True or False: Type 2 diabetics who are insulin resistant with high glucose may present with non-ketotic hyperosmolar diabetic coma?
What presents with an elevated serum osmolality and serum glucose?
Hyperosmolar non-ketotic coma
What is the goal of treatment for hyperosmolar non-ketotic coma?
Same as DKA...make patient euvolemic and euglycemic without throwing them into cerebral edema
Over how many hours should fluid replacement occur for treatment of hyperosmolar non-ketotic coma?
36-48 hours (similar to managing hypernatremic dehydraion)
What is metabolic syndrome?
A series of clinical and laboratory findings that are felt to be the result of insulin resistance
What are 4 parts to the current definition of metabolic syndrome?
1. Hyperinsulinemia or insulin resistance
4. Obesity (particularly central adiposity)
What is the management of metabolic syndrome?
Primarily weight loss and adoption of healthy lifestyle including regular exercise
True or False: There are no current recommendations for the use of metformin in treating metabolic syndrome?
What is hypercalcemia?
Serum calcium greater than 11mg/dL
What should you think if they present a patient with prolonged immobilization?
What are symptoms of hypercalcemia?
Constipation, fatigue, depression, muscle weakness, changes in sensorium (including coma)
Memory aid for causes of hypercalcemia?
A wishbone is made of calcium:
W: Williams Syndrome
I: Ingestion (Vitamin D/A intoxication, Thiazide diuretics)
S: Skeletal disorders (Dysplasias and Immobilization/Body Casts)
How is hypercalcemia treated?
High volume fluid, furosemide (Lasix), and EKG monitoring.. In rare cases calcitonin is used.
What is hypocalcemia?
Ionized calcium lower than 4.5 mg/dL (1.0 mmol/L)
Total calcium lower than 8.5 mg/dL
Name 4 components of a classic presentation of hypocalcemia.
1. Painful muscle spasms
2. Generalized seizures
4. Prolonged QT interval on EKG
What should you consider with a siezure that is resistant to diazepam?
What are 2 classic signs to watch out for with hypocalcemia?
What electrolyte abnormality do you need to be mindful of with hypocalcemia?
What is elicited by tapping just anterior to the ear lobe below the cheek bone?
What is a positive finding for Chvostek sign?
Contraction of distal muscles when you tap just anterior to the ear lobe below the cheek bone
How is Trousseau sign elicited?
By inflating the BP cuff above systolic pressure and leaving it there for 2 minutes
What is a positive finding for Trousseau sign?
When you have a carpal muscle spasm on that side after inflating the BP cuff above systolic pressure and leaving it there for 2 minutes
Memory aid for causes of hypocalcemia?
Picture somebody getting drained of all the calcium (colored white for milk)...if you were drained of your pigmentation, you would look quite PINK
I: Intake (nutritional deficiency), Immune deficiency (DiGeorge syndrome)
N: Nephrotic syndrome (with low albumin, low calcium)
K: Kidney (renal insufficiency results in higher phosphate, lower calcium, and a secondary hyperparathyroidism)
What neurological problem can occur with hypocalcemia?
A combination of hypocalcemia and hyperphosphatemia correlates with what?
What does the combination of hypercalcemia and hypophosphatemia correlate with?
What does hypocalcemia and hypophosphatemia correlate with?
Vitamin D deficiency
What is it when peripheral tissue is resistant to the effects of the parathyroid hormone (they just aren't listening) and PTH levels are high?
How does pseudohypoparathyroidism present?
High PTH and hypocalcemia
Why does pseudohypoparathyroidism occur?
Due to end organ resistance to PTH
How would someone with pseudohypoparathyroidism be described?
Developmentally delayed, short, and obese with moon facies and calcification of the basal ganglia
If you are presented with a neonate who is LGA and hypoglycemic with hypocalcemia, what should you think?
Strong probability that you are being presented with an infant of a diabetic mother, even if this isn't stated outright
Name 4 situations in which calcium may be needed emergently?
3. CCB ingestion
What is rickets?
The deficient mineralization of bone at the growth plate (so rickets can't occur after growth plates are closed)
What is it called if deficient mineralization happens at the bone matrix?
What does normal bone mineralization require?
Both calcium and phosphate
If you have an issue with calcium what type of rickets?
If you have an issue with phosphate what type of rickets?
How do kids with rickets present?
Bone pain, anorexia, decreased growth rate, widening of the wrists and knees, delayed eruption of teeth, and bowed legs. Enlarged costochonral junctions (rachitic rosary). Softening of skull bones (craniotabes).
Children on what type of medications are at risk for developing rickets?
What lab value is elevated in all forms of rickets?
True or False: Serum calcium can be normal or low in calcipenic rickets?
True... calcipenic means not enough calcium to meet needs of growing bones
What are the 3 types of calcipenic rickets?
1. Vitamin D deficient rickets
2. Vitamin D dependent rickets type 1
3. Hereditary Vitamin D resistant rickets (formerly known as Vitamin D dependent rickets type 2)
What is always elevated in calcipenic rickets?
PTH (think of this as the bone phoning home for more calcium)
What 2 issues with Vitmain D can also result in calcipenic rickets?
1. Secondary defects in Vitamin D metabolism
2. Defects in Vitamin D or calcium absorption
What 2 other types of diseases can you see rickets in?
1. Extremely severe liver disease
2. Intestinal disorders like celiac disease
What is the most common type of rickets?
Vitamin D deficient (nutritional) rickets
Name 4 risk factors to watch out for in the presenting history that should point you toward a diagnosis of nutritional rickets
1. Breast feeding without vitamin D supplementation
2. Poor exposure to natural sunlight (pay attention if they note the baby is dark skinned)
3. Low birth weight, prematurity, or both
4. Infants on strict vegan diets which exclude dairy products (if Mom was on a nondairy diet while pregnant, infant may be born with congenital rickets)
How many IU of Vitamin D do infants need daily?
If the majority of an infants intake is breast milk, what do they need?
Vitamin D supplementation starting by 2 weeks of age (Vitamin D isn't very bioavailable in breast milk)
Which ethnicity of babies are at particular risk for vitamin D deficient (nutritional) rickets?
African American...lower absorption of UV light
What is the typical presentation of Vitamin D deficient (nutritional) rickets?
African American infant, born in fall or early winter, who is being breastfed without vitamin D supplementation
What dietary issue should you be mindful of Vitamin D deficient (nutritional) rickets?
Lactose intolerance...since the patient is avoiding dairy products they are vulnerable to Vitamin D deficient rickets
Which of the calcipenic rickets is the only one where a 25-hydroxy vitamin D level will be low?
Vitamin D deficient rickets (kind of obvious)
How is Vitamin D Deficient (nutritional) rickets treated?
Vitamin D and calcium supplementation
True or False: Serum calcium and phosphorous levels may be normal in the face of rickets?
Which lab value is always elevated in rickets?
Serum alkaline phosphatase
When rickets occurs with chronic liver disease what is it usually due to?
Result of reduced availability of bile salts in the gut and subsequent decreased absorption of vitamin D (not due to the lack of hydroxylation)
How is vitamin D dependent rickets type 1 inherited?
What is vitamin D dependent rickets type 1 due to?
Inadequate renal production of 1,25 dihydroxy vitamin D
What happens to calcium and 25 hydroxy vitamin D in vitamin D dependent rickets type 1?
Serum calcium is low
25 hydroxy vitamin D is normal (liver is still doing its job)
What reflects the amount of vitamin D stored in the body?
What is the active metabolite of vitamin D?
Which organs add the 25 and 1 to vitamin D?
25 is added by the liver
1 is added later by the kidney
What is seen in the head of a patient with rickets?
Crainotabes: Delayed suture and fontanel closure, skull thickening, "frontal bossing", and bad tooth enamel
What is seen in the extremities of a patient with rickets?
Widened physes of wrists and ankles, femoral/tibial bowing
What is seen in the chest of a patient with rickets?
"Pigeon chest", rachitic rosary (costcochondral joints are enlarged)...could be shown as picture
With what type of organ disease can you see rickets?
Memory aid to remember rachitic rosary with rickets?
Vitamin D Dependent Rickets Type 1 is also known as what?
pseudo-Vitamin D-resistant rickets
What is the presentation of Vitamin D Dependent Rickets Type 1
Same as vitamin D deficient rickets
How is Vitamin D Dependent Rickets Type 1 treated?
Vitamin D2 and 1,25-dihydroxy vitamin D
What used to be known as vitamin D dependent rickets Type 2?
Hereditary Vitamin D Resistant Rickets
How is hereditary vitamin D resistant rickets inherited?
What is hereditary vitamin D resistant rickets due to?
End organ resistance to vitamin D
What is the primary difference between Type 1 and Type 2?
Type 1: 1,25-dihydroxy vitamin D is decreased due to poor or absent production
Type 2: 1,25-dihydroxy vitamin D is elevated due to end organ resistance
In phosphoenic rickets, what is the problem?
Phosphate is low
True or False: In phosphopenic rickets, the calcium and PTH may be normal?
What is the most common form of phosphopenic rickets in children and adolescents?
Due to renal phosphate wasting
What is the problem in X-linked hypophosphatemic rickets?
Excessive phosphate loss through the kidneys
How is X-linked hypophosphatemic rickets inherited?
What is the most common cause of rickets in industrialized countries?
X-linked hypophosphatemic rickets
How is X-linked hypophosphatemic rickets treated?
With phosphate supplementation...in addition, 1,25-dihydroxy vitamin D is needed
What is the
1. Underlying cause
4. Alkaline phos
6. 25-Vitamin D
7. 1,25 Vitamin D
in Vitamin D deficient rickets?
1. Nutritional deficit OR poor UV light exposure
2. Low or normal
3. Low or normal
What is the
1. Underlying cause
4. Alkaline phos
6. 25-Vitamin D
7. 1,25 Vitamin D
in Vitamin D dependent type 1 rickets?
1. 1-alpha hydroxylase deficiency
2. Low or normal
What is the
1. Underlying cause
4. Alkaline phos
6. 25-Vitamin D
7. 1,25 Vitamin D
in Hereditary Vitamin D resistant rickets?
1. End organ resistance
2. Low or normal
7. Very high
What is the
1. Underlying cause
4. Alkaline phos
6. 25-Vitamin D
7. 1,25 Vitamin D
in X-linked hypophosphatemic rickets?
1. Defect in tubular reabsorption of phosphate
2. Very low