Endocrinology Flashcards
What hormones are in the anterior pituitary and which are in the posterior pituitary?
anterior: growth hormone, prolactin, TSH, FSH, LH, ACTH
posterior: ADH, oxytocin
What defects can occur with congenital hypopituitarism
usually growth hormone deficiency and one or more of the other 5 hormones made in the anterior pituitary
What is septo optic dysplasia
abnormality of the optic nerve or chiasm (absence or hypoplasia) children are often blind or have very little vision
agenesis of the septum pellucidum and/or corpus callosum
hypothalamic insufficiency affecting both the anterior and posterior pituitary
What is associated with midface anomalies particularly a solitary maxillary central incisor
growth hormone deficiency
What is the most common tumor in children that affects the pituitary
crainiopharyngioma
What are the effects of an ectopic posterior pituitary gland
failure of the posterior pituitary to migrate toward the anterior pituitary and form the infundibulum causes problems with the portal vessels and communication between the hypothalamus and the anterior pituitary:
thus leads to anterior pituitary problems: growth hormone deficiency to panhypopituitariam
What is an indicator of the degree of problems in those with an ectopic posterior pituitary gland?
presence of pituitary stalk
if present: isolated growth hormone deficiency
if abnormal: multiple hormone deficiencies
What are some clinical manifestations of growth hormone deficiency
normal size at birth
fall off of growth curve by more than 4 SD by 1 year of age
microphallus in males
hypoglycemia and direct hyperbilirubinemia in neonate
characteristic facies over time: round head, short broad face with prominent frontal bone and depressed saddle shaped nose
high pitched voice
small gonads, sparse secondary hair
normal intelligence
How is growth hormone deficiency diagnosed
suspect when there is post natal growth failure (more than 3 SD below the curve by age 3)
Serum IGF-1 and IGH BP-3: if in the upper range of normal GH deficiency is ruled out
definitive diagnosis with lack of response to stimulation of GH production (exercise, insulin, glucagon, L-dopa, arginine, clonidine)
What is idiopathic short stature?
more than 2.25 SD below the mean
with normal GH levels
unlikely to reach a normal adult height
can now be treated with GH
What is Laron syndrome
short stature with normal GH levels
problem is at the receptor
low levels of IGF-1
treated with IGF-1
What is seen in constitutional growth delay
variant of normal growth, with slower growth rate, but after age 3 normal growth velocity
bone age is delayed
family history of growth delay is common
often have delayed puberty
will reach normal adult height with no intervention
What is seen in familial short stature
normal growth velocity
normal bone age
family history of short stature
What is seen in hormone deficiency
decrease in growth velocity
delayed bone age
sometimes family history
How is mid parental height calculated?
boys: {mom height + dad height + 13 cm }/2
girls {mom height + dad height-13 cm} /2
What are some other causes of short stature
hypothyroidism
psychosocial dwarfism
Silver-Russell: short stature, SGA, frontal bossing, triangular facies, short and incurved 5th digits and asymmetry
What are some of the side effects to growth hormone
SCFE, pseudotumor cerebri, transient carbohydrate intolerance, transient hypothyroidism, scoliosis
What causes diabetes insipidus
ADH deficiency from the posterior pituitary
or kidney unresponsive to ADH
ADH works on kidney to conserve water and make urine hyperosmolar
What causes increase in ADH
elevated osmolality, hypervolemia sodium is the strongest stimulus thirst begins with osmolality is > 295 nausea is a potent stimulus angiotensin II, insulin-induced hypoglycemia, acute hypoxia and acute hypercapnia
What are some causes of central DI
primary inherited (rare): AD wolfram syndrome and septooptic dysplasia Acquired: tumors (craniopharyngioma, optic glioma, germinomas) head injury Systemic disease: sarcoidosis, encephalitis, histiocytosis, tuberculosis
What causes nephrogenic DI
x linked inherited form lithium polycystic kidney disorder sickle cell anemia chronic pyelonephritis sarcoidosis, amyloidosis
What are the clinic findings of diabetes insipidus
polyuria and polydipsia
infants: poor feeding, poor growth, irritability, high fevers
new onset enuresis in older children
What is the diagnosis and treatment of diabetes insipidus
hyperosmolar serum dilute urine low or absent ADH suggests central DI give desmopressin DDAVP: if central DI: urine will become more concentrated and osmolality will decrease if nephrogenic: no change
Central DI: DDAVP
nephrogenic DI: low sodium with adequate protein and lots of water ) 300-400 ml/kg/day, can use thiazide, indomethacin
What are the symptoms of SIADH
hyponatremia, low serum osmolality
high urine osmolality
fluid overload with low urine output
What are some causes of SIADH
pneumonia, tumors, TB, CF, meningitis, encephalitis, head trauma, post neurosurgery
What is the treatment for SIADH
fluid restrict
treat underlying problem
What is seen with cerebral salt wasting and what is the treatment
hyponatremia
hypersecretion of atrial natriuretic peptide
increased urine output, hypovolemia
high urinary sodium excretion
low ADH
treatment: replace urine output with IV solution normal saline to 3% depending, may need oral salt replacement
What happens if there is growth hormone excess and how is that tested for?
gigantism if epiphyses are open and acromegaly if the epiphyses are closed
rapid growth, coarse facies, big hands and feet with hypogonadism
high growth hormone levels that do not suppress with glucose administration
what is sotos syndrome or cerebral gigantism
rapid growth early in childhood with no evidence of endocrine disorder
infants are > 90th percentile and grow to be > 97th percentile by 1 year of age
accelerated growth persists till age 4 or 5
puberty is at the normal time with normal adult height
big hands and feet and clumsy
poor coordination
some degree of intellectual disability
long narrow face with high forehead and small pointed chin
What are the symptoms of a prolactinoma and how is it diagnosed
amenorrhea, headache, galactorrhea
visual field defects
diagnose with MRI
usually due to an adenoma that can be resected or managed with bromocriptine
Describe beckwith-wiedemann syndrome and what screening is needed for these patients
overgrowth syndrome
hypertrophy of organs, macroglossia, hepatosplenomegaly, nephromegaly and beta cell hyperplasia resulting in hypoglycemia
at risk for wilms tumor, adrenocortical carcinoma and hepatoblastoma
need abdominal US q 3 months until 8 years old
need AFP q 6 weeks until 6 years old
What hormone starts puberty
LH begins being secreted at night 1-3 years prior to the onset of puberty
What hormone closes the epiphyses
estrogen
What is the first sign of puberty in a girl
in a boy
breast bud development
testes enlargement and scrotal thinning
How long is it from the beginning of breast buds to menarche for most girls?
2-2.5 years though it can be as long as 6 years
When does peak height velocity occur for girls, and for boys
breast stage 2-3, usually between 11-12 years old
tanner stage IV-V, usually between 13-14 years old
At what breast stage does menarche usually occur?
breast stage 4, if it occurs earlier, must work up a cause
What is the definition of late puberty for girls and for boys
delayed male puberty: no secondary sexual characteristics by 14 or if > 5 years from beginning to completion
delayed female puberty: no secondary sexual characteristics by 13 or if > 5 years have passed between the beginning and completion of puberty
What are signs of true precocious puberty in girls, in boys?
Girls: breast development and pubic hair (tumor 10% of the time)
Boys: testes > 3 ml and pubic hair (source is testes) brain tumor 50% of the time
What is the most common brain lesion that causes true precocious puberty and what is the management
hypothalamic hamartoma
ectopic neural tissue that functions as an accessory GnRH pulsatile generator
usually surgery is not done and instead treated with medication
What are some causes of central precocious puberty
idiopathic (girls)
congenital defects septo-optic dysplasia
brain tumor (craniopharyngioma, dysgerminoma, ependymoma, ganglioneuroma, optic glioma)
Other lesions (arachnoid cyst, suprasellar cyst)
Infection or inflammation: brain abscesses, encephalitis, granuloma, meningitis
Injury: head trauma, irradiation
hereditary conditions: neurofibromatosis, tuberous sclerosis
How is central precocious puberty treated
GnRH agonists:
leuprolide injection
constant infusion decreases pituitary response to GnRH and leads to decreased gonadotropin secretion
What are the symptoms of McCune Albright syndrome
café au lait spots
fibrous dysplasia of the skeleton
hyperfunctioning endocrine organs, often presents as peripheral precocious puberty
more common in girls with ovarian cyst and vaginal bleeding
What tumors can cause peripheral precocious puberty
HCG, human chorionic gonadotropin secreting tumors
see penile enlargement and pubic hair without testicular enlargement
could be in the gonad, adrenal gland or the brain
What is premature thelarche and how should it be monitored
isolated breast development and is a diagnosis of exclusion
occurs first 2 years of life
no adrenal gland involvement
rule out excessive exposure to estrogen from cosmetics or soy products
order estradiol, LH and FSH and a bone age (these should all be normal for age)
monitor that it is not the first sign of precocious puberty
What is premature adrenarche
variant of normal but diagnosis of exclusion
signs of isolated pubic hair, body odor, acne before 8 years of age in girls and 9 in boys with no other involvement of gonads, breast development
What tests should be done if there is premature adrenarche?
must rule out exogenous exposure and adrenal tumors and late onset CAH
DHEAS, testosterone, androstenedione, 17-hydroxy-porgesterone and bone age
These should be normal, with only DHEAs being mildly elevated.
If abnormal need to rule out late onset CAH
What increased thyroid binding globulin and thus increases total T4?
pregnancy, OCPs,
tamoxifen, clofibrate, narcotics,
hepatitis, biliary cirrhosis
What decreases thyroid binding globulin and thus decreases total T4?
androgens
glucocorticoids
nephrotic syndrome
inherited TBG deficiency
What is radioiodine uptake used for? What diseases are associated with elevated vs decreased findings?
differentiating non-pituitary thyrotoxic states
get a number that tells the percentage of the dose taken up into the thyroid
increased:
graves, hot nodule (multinodular goiter, toxic solitary nodule, hCG-secreting tumor)
decreased:
self limited thyroiditis
thyroiditis factitia
amiodarone
What is a thyroid scan used for?
give a dose of technetium 99 and scan to get a picture
for nodular disease, if a nodule is hot or cold
What are causes of congenital hypothyroidism
thyroid dysgenesis or defective thyroid embryogenesis
maternal antibodies if mom has graves disease
transient congenital hypothyroidism due to iodine deficiency in mom
What are the symptoms of congenital hypothyroidism
asymptomatic at birth then develop feeding problems, constipation, sluggishness, lack of interest, choking spells and somnolence, large tongue, hypothermia umbilical hernia genital and extremity edema bradycardia, cardiomegaly anemia wide open posterior fontanelle slow bone maturation absent distal femoral epiphysis
How is low TBG tested for and what is the management
infant will have low total T4 and normal TSH and free T4
obtain TBG level
do not treat infant
what is often seen in infants with central hypothyroidism
TSH is low, due to a deficiency in TRH
often infant presents with signs of other pituitary defects with hypoglycemia, hyperbilirubinemia and micropenis with midface anomalies
How is hypothyroidism treated
levothyroxine 10-15 micrograms/kg/day in a crushed tab
do not give with soy or iron
start with in the first two weeks to prevent developmental delay
What are symptoms seen with hypothyroidism in older children?
greater weight for age than height delayed bone age slow tendon reflexes constipation somnolence, behavior changes growth failure SCFE
Who should be screened frequently for hypothyroidism
those with type 1 diabetes, down syndrome, turner, kleinfelter
What antibodies are positive with hashimoto’s thyroiditis. What is the treatment?
antithyroglobulin
anti-thyroperoxidase
can be present in normal individuals but are indicative especially if there is a family history
What should be done for the patient who is euthyroid but has antibodies
check thyroid levels every 6 months and treat if they become hypothyroid
What is subacute of de Quervain Thyroiditis and how does it present
self limited inflammation of the thyroid often after an upper respiratory infection
fever, thyroid tenderness, and pain
initially symptoms of hyperthyroidism followed by hypothyroidism
lasts 2-9 months
controlled with analgesics or if severe prednisone
What is suppurative thyroiditis and how is it treated
bacterial infection of the thyroid usually the left lobe
if it occurs there is usually an embryologic remnant
fever, thyroid enlargement, pain and local tenderness
thyroid function is normal
treat with appropriate antibiotics (can do fine needle aspiration for culture)
usually staph, strep pyogenes or pneumoniae
What is graves disease and how does it present
most common cause of hyperthyroidism in children
diffuse thyroid hyperplasia due to thyroid-stimulating immunoglobulin
muscle weakness, anxiety, palpitations, increase appetite, weight loss or weight gain
behavior problems
hypertension, tachycardia, cardiomegaly
tremor, excessive perspiration, widened pulse pressure
thyroid bruit
How is graves disease treated
B blockers for controlling manifestations
three ways to stop increased production:
Radioactive iodine ablation: still a chance of relapse, use to have concerns for leukemia and thyroid cancer after treatment, but these concerns have not panned out
Surgical removal: risk of hypoparathyroidism, damage to recurrent laryngeal nerve
Medical management: methimazole (PTU can be used but less recommended in children due to hepatotoxicity)
What are the side effects of PTU and methimazole
skin rashes
agranulocytosis (sore throat, mouth ulcers)
What is neonatal thyrotoxicosis
mom’s thyroid antibodies cross the placenta and affect baby
Mom may be treated for hypo or hypothyroidism but, antibodies are still present
How does neonatal thyrotoxicosis present
irritability, flushing, tachycardia, hypertension, thyroid enlargement and exophthalmos some with arrhythmias and high output cardiac failure (most common cause of death)
treat with sedatives, digitalis
lugol solution (iodine and potassium iodine) response in 24-36 hours
can use propranolol
How can thyroid cancer present
solitary thyroid mass with a consistency different than the rest of the thyroid
solitary nodule prior to 20 years of age is likely to be malignant 26%
may have cervical adenopathy and hypocalcemia with hyperphosphatemia
What are risk factors for thyroid cancer
history of radiation to the neck or head a solitary nodule > 1 cm with fixed, hard or irregular borders solitary nodule with calcifications family history of MEN rapidly growing nodule that is firm or hard satellite lymph nodes hoarseness or dysphagia evidence of distant metastasis
