Endocrine/ Metabolism Flashcards
what are the symptoms of hypocalcemia
fatigue, anxiety, depression initially;
parasthesia, tetany (involuntary contractions) of the lips, face and extremities, seizures and QT prolongation in severe cases
in obese women what provides more continual estrogen despite loss of ovarian estrogen production
peripheral fat contains aromatase which converts endogenous androgens to estrogens so obese patients have increased aromatase activity leading to increased estrogen even despite menopause
a patient with hypogonadotropic hypogonadism as well as low TSH and mild hyperprolactinemia is likely suffering from what condition
nonfunctional pituitary adenoma (produces just the alpha subunit and suppresses other trophic hormones as well due to mass effect)
infants born to mothers with Grave’s disease are at increased risk for high circulating levels of what? what is the treatment for symptomatic patients?
anti-TSH receptor antibodies (activating)
Tx: methimazole and beta blockers for symptomatic patients until self-resolution
does thyroid hormone cross the placenta
not in significant amounts
algorithm for assessing precocious puberty (i.e. before age 8)
if bone growth is elevated check basal LH, if basal LH is elevated it is gonadotropin-dependent (most commonly idiopathic), if basal LH is low and does not respond to GnRH it is gonadotropin independent (likely CAH or a gonadal tumor), if LH is low but increases with GnRH stim then it is likely gonadotropin dependent
what should you be careful not to give when treating symptoms of pheochromocytoma
do not give beta blocker first; make sure to start antihypertensive therapy with alpha blocker before beta as unopposed alpha adrenergic activity can cause rapid increases in BP
what is the initial therapy for prolactinoma
dopamine agonist (cabergoline); if sx do not improve then consider surgery surgery is unlikely to be needed for microadenoma (tumor
what happens to the amount of albumin bound to calcium vs. ionized in acidosis vs. alkalosis
acidosis: more H+ bound to albumin leaving less space for calcium resulting in high ionized calcium concentration
alkalosis: fewer H+ bound to albumin resulting in increased binding of calcium to albumin and low ionized calcium concentration
A patient has surgery and develops tachycardia, hypertension, lid lag, tremor, agitation, delirium, warm moist skin, nausea, vomiting and diarrhea. What diagnosis do you suspect and what is the treatment?
thyroid storm (occurs in predisposed patients with untreated hyperthyroidism after surgeries or iodine toxicity) Tx: TFT's, propranolol, PTU followed by iodine solution after an hour (decrease hormone synthesis then decrease release), glucocorticoids (decrease peripheral T4-->T3 conversion)
how do you differentiate between Cushing’s disease (ACTH-secreting pituitary adenoma) and ectopic ACTH secretion
dexamethasone suppression test: failure to suppress serum cortisol to
what should happen to a woman’s levothyroxine dose during pregnancy
it should increase: maternal hypothyroidism causes decreased IQ in infant
a diabetic patient has abdominal bloating, decreased appetite, early satiety and nausea; what is the problem and treatment?
diabetic gastroparesis
Tx=metoclopramide (has prokinetic and antiemetic properties) or erythromycin; optimize diabetes control; small, frequent meals (to decrease postprandial hypoglycemia due to malabsorption)
what plasma renin and aldosterone test values are suggestive of primary hyperaldosteronism
plasma aldosterone to renin activity ratio > 20
plasma aldosterone > 15ng/dL
in hyperaldosteronism, what prevents severe rapid hypernatremia and volume overload
aldosterone escape promotes spontaneous diuresis
what is the treatment for patients symptomatic with Paget’s disease (you don’t need to treat asymptomatic patients)
bisphosphanates (calcitonin is weaker, but used if pt cannot tolerate bisphosphanates)
what are the four symptoms of MEN2B
- medullary thyroid carcinoma
- pheochromocytoma
- mucosal neuromas
- marfanoid habitus
what are the three symptoms of MEN2A
- medullary thyroid carcinoma
- pheochromocytoma
- parathyroid hyperplasia
what are the symptoms of MEN1
- pituitary tumor
- primary hyperparathyroidism
- enteropancreatic tumors
what does hypomagnesemia do to calcium
hypomagnesemia causes hypocalcemia via PTH resistance
what is the difference between sick euthyroid and subclinical hypothyroidism
sick euthyroid: in acutely or severely ill patients total thyroid and free T3 are decreased (due to poor peripheral conversion to T3, then eventually T4 and TSH decrease)
subclinical hypothyroidism: TSH is elevated, but T3 and T4 are normal and patient is asymptomatic
Hurthle cells are seen in which cancers
follicular and papillary thyroid cancers
why must follicular thyroid neoplasm show invasion of capsule into bloodstream before diagnosis can be made of carcinoma vs. adenoma
follicular carcinoma is well-encapsulated and does not show much nuclear change so invasion is the only way to distinguish carcinoma from adenoma
what is the most common thyroid malignancy? describe its characteristics
papillary thyroid carcinoma: unencapsulated, slow growing, invasion of regional structures and lymph nodes, good prognosis, on histology ground glass cytoplasm and psamoma bodies, pale nuclei with central grooving and inclusion bodies
describe neuropathic pain in diabetes (distribution, characteristic pain of small vs. large fiber)
“stocking glove” distribution; small fiber involvement=pain, allodynia, parasthesias; large fiber involvement=loss of vibration, touch, pressure, and proprioceptive sensation
what are the treatments of diabetic neuropathic pain in order of preference
- TCA’s
- gabapentin
- NSAIDs
what happens to calcium and PTH in osteoporosis
calcium, PTH, phosphate and alkaline phosphatase are normal in osteoporosis despite lower bone density
what are carcinoid tumors and when does carcinoid syndrome develop
slow growing neuroendocrine tumors found in the small intestines, prox colon or lungs; carcinoid syndrome develops when mets to the liver prevent breakdown of secreted hormones (5HT, histamine, VIP)
how can you differentiate between primary polydipsia (DM and psychogenic), central DI and nephrogenic DI
primary polydipsia=low serum Na due to excessive water intake
central DI=high serum Na (>150) due to impaired thirst mechanism that is ADH-mediated
nephrogenic DI=normal to mildly elevated Na (142-150) due to intact thirst
what are the symptoms of a glucagonoma
necrolytic migratory erythema, hyperglycemia, GI distress, weight loss, ataxia, proximal muscle weakness, venous thrombosis
how do you interpret a water deprivation test
for polyuria and low urine Osm do a water deprivation test: if urine osm increases to >600 after 2-3 hours deprivation => primary polydipsia
if not do a desmopressin test: if urine osm increases by 50-100% it is central DI
if urine osm doesn’t increase after desmopressin it is likely nephrogenic DI
what is the medical therapy for Conn syndrome (used for pts who can’t undergo surgery or have bilateral adrenal hyperplasia)
spironolactone (also has antiandrogenic effects) or eplerenone (more selective aldosterone antagonist)
adrenal insufficiency and adrenal calcifications on CT suggest what etiology
adrenal tuberculosis (most common cause of adrenal insufficiency in developed world)
what are the best measures of response to treatment of DKA
serum anion gap and serum betahydroxybutyrate (more common ketone than acetoacetate)
what is the risk of HPA axis suppression for patients taking low dose steroids (
no risk of HPA axis suppression
at what gestational age should the 1 hour oral glucose tolerance test be given; and how is the decision made for following up with a 3 hour GTT
at 24-28 weeks the 1hr GTT is given
if glucose is >140 one hour after 50g load then follow up with 3hr GTT
what is the classic triad of milk alkali syndrome
hypercalcemia, renal insufficiency, metabolic alkalosis
what hormone allows you to distinguish an adrenal androgen-secreting tumor vs. a gonadal androgen-secreting tumor
DHEA-S (dihydroepiandrosterone-sulfate)
androstenedione, DHEA and testosterone are produced by both the ovaries and the ovaries and the adrenals, whereas DHEA-S is only produced by the adrenals
what hormone is the key player in causing refeeding syndrome and what are the major lab abnormalities/ complications?
insulin (feeding after starvation causes increased insulin that calls for nutrients that aren’t there to anabolize)
- hypophosphatemia, hypomagnesemia, hypokalemia, low thiamine
- complications: cardiac arrythmias, heart failure, Wernicke’s
what is the preferred treatment for Grave’s disease
radioactive iodine ablative therapy
tight glycemic control (Hgb A1c
microvascular diseases (retinopathy, nephropathy)
no data to support overall mortality benefit or benefit for macrovascular (stroke, MI)
what are the indications for starting a statin
significant atherosclerotic disease, LDL >190, age 40-75 with diabetes, 10 year ASCVD risk > 7.5%
what is the order of diagnostic tests for workup of acromegaly
IGF-1 –> oral glucose suppression test –> brain MRI
once azotemia develops in the progression of diabetic nephropathy intensive control of what parameter is most important for slowing the decline in renal function
intensive control of blood pressure
what three initial diagnostic blood tests should you order for a patient in whom you suspect adrenal insufficiency
morning serum cortisol, ACTH and cosyntropin stimulation test
which therapy for Grave’s disease causes an initial worsening of opthalmopathy
radioactive iodine ablative therapy
what should you suspect in a patient with cold intolerance, hypoglycemia, decreased libido and hypopigmentation?
panhypopituitarism (note aldosterone is not affected since the RAS axis is not mediated by the pituitary)
what does a prussian blue stain of the urine tell you
detects the presence of hemosiderin which indicates hemolysis
ectopic ACTH is mainly associated with what conditions
small cell lung cancer and bronchial carcinoid
how can hypokalemia be seen in Cushing’s
cortisol has mineralocorticoid activity when it is not in its inactive state of cortisone
what is the difference between steroid acne and adolescent acne
adolescent acne has comedones (blackheads and whiteheads), steroid acne does not
in the workup for primary hyperthyroidism if you see low radioactive iodine uptake what subsequent study should you do and how do you interpret it
check thyroglobulin level; if it is low this indicates exogenous thyroid hormone, if it is high this indicates glandular source (thyroiditis, iodide exposure, extraglandular production)
proximal muscle weakness can be seen in Cushing’s as well as what other endocrine disorder
hyperthyroidism
what can hypothyroidism do to cholesterol
hypothyroidism can cause hyperlipidemia (increased LDL) and hypertriglyceridemia
isolated premature adrenarche in a young (
the adrenal gland (androgens are mainly produced there and an ovarian tumor would likely cause thelarche as well)
what are the levels of calcium, phosphorus, PTH and alkaline phosphatase in Paget’s
normal Ca, phosphorus and PTH
increased alkaline phosphatase
what test is done to predict risk of diabetic foot ulcers
monofilament testing
a patient on propylthiouracil develops a sore throat and fever; what is the next best step in management
discontinue propylthiouracil before doing anything else (WBC count, cultures, abx)
a toddler who has hypotension, abdominal pain, hematemesis, metabolic acidosis and radiopaque tablets on x-ray should receive what treatment
deferoxamine for iron poisoning
if you suspect lead poisoning what is the first diagnostic test you should do
fingerstick lead level followed by venous lead level if abnormal
what are the steps for managing a caustic ingestion (e.g. sodium hydroxide aka lye)
remove clothing, IV hydration, chest and abdominal x-rays with water soluble contrast to r/o perforation, upper endoscopy to evaluate extent of caustic injury
how can you differentiate between a beta cell tumor and non-beta cell tumor in a patient with episodes of hypoglycemia
IGF-II will be elevated in a non-beta cell tumor (mesenchymal tumor); C-peptide will be elevated in a beta cell tumor
what is the antidote for TCA toxicity
sodium bicarbonate (prevents TCA-induced inhibition of sodium fast channels in myocardium to prevent/resolve QRS widening)
sodium thiosulfate is the antidote for what poisoning
cyanide poisoning
a patient ingests a toxin and develops calcium oxalate stones; what is the toxin and what is the treatment
ethylene glycol toxicity
treat with fomepizole to prevent conversion of ethylene glycol to oxalic acid and glycolic acid
what is adrenoleukodystrophy
accumulation of long chain fatty acids in the adrenal glands leading to adrenal insufficiency
how do you manage acetaminophen ingestion? (algorithm)
if single dose >7.5g or 150mg/kg in peds or chronic ingestion check timing; if
what is the antidote for diphenhydramine overdose
physostigmine
what are the two main toxins in the air of house fires
cyanide (HCN) and carbon monoxide
what are the three ways you can treat cyanide poisoning
- hydroxocobalamin
- sodium thiosulfate
- nitrites (to induce methemoglobinema and have ferric iron in hemoglobin bind up the cyanide)
what is the mechanism of action of cyanide toxicity
cyanide binds and inhibits cytochrome oxidase in the electron transport chain
what distinguishes methanol poisoning from ethylene glycol poisoning (both cause anion gap met acidosis)
optic disc hyperemia (whereas ethylene glycol damages the kidneys with Ca oxalate stones, methanol damages the eyes leading to blindness)
a patient was at an indoor barbecue and now has a pinkish hue to skin and tachycardia/tachypnea; what diagnostic test should you do
check carboxyhemoglobin levels for suspected CO poisoning
a patient with carbon monoxide poisoning has normal pulse ox readings; how is this possible
don’t trust the pulse ox in CO poisoning; carboxyhemoglobin is tricky and gets read as oxygenated hemoglobin; GIVE 100% OXYGEN VIA NRB RIGHT AWAY REGARDLESS
what are three key symptoms of VIPoma
watery diarrhea (secretory), hypokalemia, hypochlorhydria (due to decreased gastric acid secretion); note: tumor will likely be in pancreatic tail
increased appetite, dry mouth and conjunctival injection are symptoms of what substance use
marijuana
when a hypothyroid woman starts oral estrogen replacement what happens to her thyroid levels
oral estrogen increases TBG (note transdermal does not) therefore requiring more thyroid hormone to saturate the increased TBG and increasing the required levothyroxine dose for a woman on thyroid hormone (the body cannot naturally compensate)
how does sodium bicarb treat QRS prolongation in TCA overdose (mechanism)
pH and extracellular sodium hinder ability of TCA’s to bind to fast sodium channels
what is the antidote for beta-blocker intoxication
glucagon
you should screen all patients for diabetes who _____
have BP > 135/80, are age 45 or older, or have risk factors for diabetes
hashimoto’s has an increased risk of complication by what thyroid malignancy
lymphoma of the thyroid
what does hyperthyroidism do to bones
increases osteoclastic bone resoprtion leading to decreased bone mass and hypercalcemia
what are the predisposing factors for thyroid storm and how is it treated
predisposing factors: surgery, acute illness, childbirth, iodine load (contrast)
tx: propranolol and steroids, admit to ICU
in a patient with familial medullary thyroid carcinoma what do you have to screen for before thyroidectomy?
pheo; check VMA
make sure they don’t have pheo so that there’s no risk of hypertensive crisis during surgery
