Endocrinology Flashcards
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?
Testicular enlargement
What defines testicular enlargement?
Testicular length greater than 2.5cm… indicates the onset of puberty
When do boys typically being puberty (testicular enlargement)?
Between 10-11
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?
Klinefelter
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?
Marijuana
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?
- Constitutional delay of puberty
- Functional gonadotropin deficiency (anorexia nervosa)
- 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?
Yes
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?
Premature adrenarche
What are the 3 lab findings associated with premature adrenarche?
- Elevated serum dehydroepiandosterone (DHEA)
- Elevated serum dehydroepiandrosterone-sulfate (DHEA-S)
- Low concentrations of testosterone
Does premature adrenarche require treatment?
No
What are 3 things that can cause adrenarche in males or females?
- Exogenous androgen
- Endogenous androgen-secreting tumor
- 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?
Insulin resistance
What can be an early sign of polycystic ovary syndrome in adolescent girls?
Premature adrenarche
What are 2 benign conditions that don’t represent true precocious (central) puberty?
- 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?
10%
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?
- Usually benign an due to premature activation of hypothalamic-pituitary axis
- Exogenous estrogen
- Estrogen-producing tumor
What are some sources of exogenous sex steroids?
- Skin preparations
- Oral contraceptive medication exposure
- Weight lifting steroids
- 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?
- Male patients
- Younger than 6
- Very rapidly advancing bone age
- 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”
Androgenic
Change in vaginal color and more prominent labia minora
Estrogenic
What test can be done to look for an adrenal (premature appearance of pubic hair) or ovarian (premature breast development) mass?
US
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.
- Hamartoma
- Hydrocephalus
- Arachnoid or ventricular cysts
- Meningitis
- Encephalitis
- Neoplasms
- CNS trauma
Which 3 lab tests help differentiate peripheral from central endocrinology disorders?
- LH
- FSH
- Adrenal steroids
What can ambiguous genitalia be confused with?
Micropenis
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?
Panhypopituitarism
What should you think in a patient who presents with a micropenis and hypoglycemia?
Panhypopituitarism
If you suspect panhypopituitarism, what should you do next?
Check ALL pituitary hormones
What 3 syndromes can panhypopituitarism be a part of?
- Prader-Willi (sick Willy)
- Kallmann (poor sense of smell)
- 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?
X-Linked
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?
- 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?
- Males: No ambiguous genitalia, but there could be excessive scrotal pigmentation
- Females: Ambiguous genitalia
What are some descriptions they will use for female ambiguous genitalia?
- 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?
Autosomal Recessive
What can be due to cortisol production being blocked?
CAH
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?
21-hydroxylase deficiency
What lab values are seen in the salt-wasting variety of CAH?
- Hyperkalemia
2. Hyponatremia
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?
17-hydroxyprogesterone assay
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
True
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?
- Aldosterone
2. Cortisol
Which hormone secreted by the adrenal glands helps control the amount of salt and fluid in the body?
Aldosterone
Which hormone secreted by the adrenal glands helps control how the body uses sugar and how it responds to stress?
Cortisol
What is most likely to occur in primary adrenal insufficiency because of the associated mineralocorticoid deficiency and salt loss?
Adrenal crisis
True or False: Adrenal crisis is a medical emergency that may lead to shock and death if not recognized and treated promptly
True
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?
- Hypoglycemia
- Hyponatremia (“salt-wasting”)
- Hyperkalemia
What are the 3 steps to treating and adrenal crisis?
- Give 20mL/kg of D5NS (with no K) IV over 1 hour
- Add IV hydrocortisone
- 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.
- Autoimmune disease
- Infection
- Idiopathic
* 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?
- Salt wasting
- Hyperkalemia
- Hyponatremia
(Fatigue and weight loss are other signs)
How are patients with adrenal insufficiency usually treated?
- 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?
No
What stimulates the pituitary to release ACTH?
CRH
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)?
Adrenals
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?
Cushing disease
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)?
- 24-hour urinary free cortisol excretion
- Midnight sleeping plasma cortisol level
- 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?
Undetectable
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?
Pituitary MRI
What is the peak growth velocity prior to puberty?
5-6 cm/year
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?
1-2 inches
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?
- Kid with headaches and growth attenuation due to a space-occupying lesion
- 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?
- Usually during infancy (around 6 months)
2. Slowed growth
What is the triad of congenital growth hormone deficiency?
- Micropenis
- Hypoglycemia
- Short stature
Name 3 clues to congenital growth hormone deficiency (besides micropenis, hypoglycemia, and short stature)?
- Septo-optic dysplasia
- Breech presentation
- 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
NOT:
- 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?
Males