Endocrinology Flashcards
What is primary (Addison’s disease)?
autoimmune, infections, disease of the adrenal gland = decrease in cortisol secretion
- adrenal gland destruction causing lack of cortisol and aldosterone secretion (usually autoimmune)
- autoimmune (70%), infectious (tuberculosis), vascular (thrombosis/hemorrhage), metastatic, medications (rifampin, barbiturates, phenytoin, ketoconazole)
- dx: increased ACTH, decreased cortisol, decreased aldosterone
What is secondary adrenal insufficiency?
pituitary adenoma or discontinuation of steroid - pituitary failure
- exogenous steroid use (most common); hypopituitarism
- dx: decreased ACTH, decreased cortisol, normal aldosterone
What is adrenal crisis?
acute adrenal insufficiency
How is adrenal insufficiency dx?
- 8 am serum cortisol and plasma ACTH alone with ACTH stimulation test
- high ACTH, low cortisol = primary
- low SCTH, low cortisol = secondary
- CRH stimulation test: differentiates between causes of adrenal insufficiency
- primary/Addison’s (adrenal): high ACTH, low cortisol
- secondary (pituitary): Low ACTH, low cortisol
- adrenal autoantibodies can be assessed; CXR for TB (CT of adrenals)
- autoimmune: atrophied adrenals
- TB/granulomas: enlarged adrenals + calcification
- bilateral adrenal hyperplasia = genetic enzyme defect
How is the tx for adrenal insufficiency?
- addison’s: cortisol replacement therapy + androgen replacement
- glucocorticoid + mineralocorticoid = hydrocortison = 1st line, fludrocortisone for primary Addison’s disease only
- secondary: cause = focus of treatment (pituitary adenoma resection, wean steroid therapy slowly)
What is hyperthyroidism?
is the production of too much thyroxine hormone
-It can increase metabolism and accelerate the body’s metabolism, causing unintentional weight loss and a rapid or irregular heartbeat
What is the etiology of hyperthyroidism?
grave’s disease (autoimmune), toxic adenoma, thyroiditis, pregnancy, amiodarone
What are the features of hypertyroidism?
weight loss, anxiety, war, moist skin, onycholysis, insomnia, fine tremor, fatigue, muscle cramps, weakness, amenorrhea, tachycardia, palpitations, systolic HTN, PVCs, fib, brittle hair, heat intolerance, hyperreflexia
- graves - diffuse goiter with a bruit, exophthalmos, pretrial myxedema
- thyroid storm - fever, tachycardia, delirium
How is hyperthyroidism?
- TSH (best test)
- decreased in primary disease (decrease TSH and increase free T4)
- elevated in secondary disease (increase TSH and increase free T4)
- T4: elevated although may be normal
- RAIU study shows increased uptake in graves disease and toxic multi nodular goiter
- graves: diffusely high uptake
- toxic multi nodular: discrete areas of high uptake
What are the antibodies with hyperthyroidism?
graves: anti-thyrotropin antibodies
What is the tx for hyperthyroidism?
- beta-blockers (symptomatic), methimazole/propylthirouacil, radioactive iodine, thyroidectomy
- thyroid storm - prompt beta-blockers, hydrocortisone, methimazole/propylthiouracil, iodine
- thyroidectomy - most likely complication is recurrent laryngeal nerve damage (hoarseness)
What do you do about antithyroid drugs during pregnancy?
propylthiouracil used to be the drug of choice during pregnancy because it causes less severe birth defects than methimazole, but experts now recommend that propylthiouracil be given during the first trimester only, this is because there have been rare cases of liver damage in people taking propylthiouracil, after the first trimester, women should switch to methimazole for the rest of the pregnancy
-for women who are nursing, methimazole is probably a better choice than propylthiouracil (to avoid liver side effects)
What is Cushing’s syndrome?
a collection of signs and symptoms due to prolonged exposure to excess cortisol
-symptoms from increase cortisol secretion, it doesn’t specify cause or source of excess
What is cushing disease?
ACTH secreting pituitary micro adenoma usually very small on anterior pituitary; F 3x > M
-secondary - increase cortisol due to ACTH excess, typically caused by a pituitary adenoma - ACTH causes adrenals to secret cortisol
What are the features of Cushing disease?
- hypercortisolism (increase cortisol) = obestiy (buffalo hump, moon facies, supraclavicular pads), HTN, thirst, polyuria, hypokalemia
- proximal muscle weakness, pigmented striae, backache, headache, oligomenorrhea/amenorrhea/ED; emotional lability/psychosis
How is Cushing disease dx?
confirming high cortisol with a 24 hr urine free cortisol, late-night serum cortisol, and/or low-dose dexamethasone suppression test
- 24-hour urinary free cortisol is the most reliable index of cortisol secretion
- once confirmed, the source of the high cortisol needs to be determined with an ACTH level
- a high ACTH level indicated an ACTH dependent cause, a low ACTH level indicates an ACTH independent cause (plasma or serum ACTH <20 pg/mL suggests adrenal tumor
- if it is an ACTH dependent cause, an MRI of the brain should be done to look for pituitary adenoma (cushing disease), if it is an ACTH independent cause, a CT of adrenals should be done to look for an adrneal mass such as an adenoma
What is low dose dexamethasone suppression test?
- give a steroid (dexamethasone) = failure of steroid to decrease cortisol levels is diagnostic = proceed next to high dose dexamethasone suppression test = no suppression = Cushing’s syndrome
- suppression < 5 ugs/dL excludes Cushing with some certainty
What is the tx for Cushing disease?
transsphenoidal selective resection of pituitary tumor cures 75-90%
- Irradiation provides remission in 50-60%
- 95% 5-year survival
What is hypothyroidism?
95% are autoimmune; many associated with other autoimmune issues
-hashimoto’s (chronic lymphocytic/autoimmune), previous thyroidectomy/iodine, ablation, congenital
What are the features of hypothyroidism?
weakness, dry/coarse hair, lethargy, slow speech, cold intolerance, eyelid edema, forgetfulness, facial edema, constipation, coarse hair, weight gain, facial dullness, depression, anemia, bradycardia, hyperreflexia, enlarged thyroid
How is hypothyroidism dx?
the best test is TSH, hasimoto’s: antithyroid peroxidase, antithyroglobulin antiboides
- normal/low normal free T4 and TSH = euthyroid
- low free T4 and elevated TSH = primary hypothyroid
- low free T4 and low/normal TSH = secondary hypothyroid
- normal free T4 and elevated TSH = subclinical hypothyroid
What is the tx for hypothyroidism?
levothyroxine
-check levels of thyroid frequently
What is diabetes insipidus?
caused by a deficiency of or resistance to vasopressin (ADH), which decreases the kidneys’ ability to reabsorb water, resulting in massive polyuria
What is central diabetes insipidus?
deficiency of ADH from posterior pituitary/hypothalamus
-no ADH production most common type: idiopathic, autoimmune destruction of posterior pituitary from head trauma, brain tumor, infection, or sarcoidosis
What is nephrogenic diabetes insipidus?
lack of reaction to ADH
-partial or complete insensitivity to ADH: caused by drugs (lithium, amphoterrible), hypercalcemia and hypokalemia affect the kidney’s ability to concentrate urine, acute tubular necrosis
How is diabetes insipidus dx?
serum osmolality (concentration) is high (unable to stop the secretion of water into the kidneys so blood becomes more concentrated) and urine osmolality is low because it is so dilute
- water depression test - simplest/most reliable method - continues production of dilute urine despite water deprivation
- desmopression stimulation test:
- central: reduction in urine output indicating a response to ADH
- nephrogenic: continued production of dilute urine (no response to ADH) because kidneys can’t respond
What is the tx for diabetes insipidus?
- central = desmopressin/DDAVP
- nephrogenic = sodium and protein restriction, HCTZ, indomethacin
What are the causes of nonketotic hyperglycemia?
- most commonly seen in type 2 DM in the setting of physiological stress
- high blood sugar results in high osmolarity without significant keto acidosis
What is the presentation of nonkeotic hyperglycemia?
- onset is typically over days to weeks
- altered level of consciousness
- signs of dehydration, weakness, leg cramps
- vision problems
What are the precipitating factors of nonkeotic hyperglycemia?
- acute infection and other medical conditions
- drugs that impair glucose tolerance (glucocorticoids) or increase fluid loss (diuretics)
- nonadherence to diabetes treatment
What are the complications of nonketotic hyperglycemia?
- seizures
- disseminated intravascular coagulopathy
- acute renal failure
- ARDS
- rhabdomyolysis
How is nonketotic hyperglycemia dx?
- blood sugar greater than 30 mol/L (600 mg/dL)
- osmolatiry greater than 320 mOsm/kg
- pH above 7.3
What is the tx for nonkeotic hyperglycemia?
- intravenous normal saline 0.9%
- IV insulin (as long as serum potassium is >3.3 mEq/L)
- low molecular weight heparin to decrease the risk fo blood clotting
- the goal is slow decline in blood sugar levels
- potassium replacement is often required
- hydration alone can sometimes precipitously decrease plasma glucose, so insulin dose may need to be reduced
What are the pearls of nonkeotic hyperglycemia?
- quick reduction is osmolality can lead to cerebral edema
- Infections, nonadherence and certain drugs can trigger marked glucose elevation, dehydration, and altered consciousness in patients with type 2 diabetes
- patients have adequate insulin to prevent keto acidosis
- target plasma glucose in acute treatment is between 250 and 300 mg/dL
- give potassium replacement depending on serum potassium levels
What are type 1 diabetes mellitus?
MC in young people
- little to no endogenous insulin secretion; elevated plasma glucagon pancreatic B cells don’t respond to stimuli
- most are autoimmune (90%) with antibodies to insulin, islet cells, and glutamic acid decarboxylase
- sx: polyuria, polydipsia, polyphagia, nocturia, rapid weight loss despite normal/increased appetite, blurred vision, glucosuria
- random plasma glucose > 200 mg/dL, blurred vision, pruritus, weakness, paresthesias, vulvuovaginitis
How is type 1 diabetes mellitus dx?
random plasma glucose > 200 mg/dL with classic symptoms or fasting >126 or > on more than one occasion
-HbA1c > 6.5% or higher
How is type 1 diabetes mellitus tx?
- diet (mediterranean)
- insulin: regular insulin absorbed most rapidly in the abdomen
- daily aspirin based on 10-year CVD risk; careful foot care, regular ophthalmology exams, moderate exercise, meticulous personal hygiene, prompt treatment of infection
- adults show aim to get at least 150 minutes of moderate or 75 minutes of vigorous physical activity a week, which is consistent with prior guidance
What is type 2 diabetes mellitus?
younger persons who overweight/obese; central obesity
-features: polydipsia, polyuria, fatigue, candida vaginitis, skin infections, blurred vision, poor wound healing