Endocrinology Flashcards
Hormones of the posterior pituitary gland
ADH and oxytocin
Neoplasias of MEN1, 2a and 2b; what genes are affected
MEN1: (men gene) parathyroid, pancreatic, pituitary
MEN2a: (ret gene) parathyroid, medullary, pheochromocytoma
MEN2b: (ret gene) Marfanoid/ mucosal neuromas, medullary, pheochromocytoma
What are 8 causes of panhypopituitarism
Anything that compresses or damages the pituitary gland.
Tumors: rather cleft cyst, craniopharyngeoma, meningiomas
Trauma and radiation
Hemochromatosis, sarcoidosis, histocytosis
Infection: TB, fungi, parasites
Autoimmune diseases
Post-Partum necrosis; sheehans syndrome
Symptoms of panhypopituitarism are based on what hormones are deficient; what symptoms would be seen in men/women deficient in
1) prolactin
2) LH/FSH
3) GH
4) TSH
5) ACTH
1) Prolactin: men will have no symptoms, women will only have symptoms if they are post-partum and will complain of no lactation
2) LH/FSH: men will not make testosterone or sperm, women will not ovulate or menstruate normally and will become ammenorheic. Both will have decreased libido, decreased body hair and men will have erectile dysfunction.
3) GH: children will present with dwarfism, adults will have few overt symptoms (reduced muscles mass, central adiposity and increased LDL)
4) TSH: Hyponatremia
5) ACTH: hypoglycemia
Define diabetes insipidus and give causes for both types
Central diabetes insipidus: decreased secretion of ADH from posterior pituitary; can be caused by any destruction of the brain from stroke, tumor, trauma, infection, hypoxia, infiltrative diseases
Nephrogenic diabetes insipidus: reduced response to or action of ADH at the kidney; causes chronic pyelonephritis, Amyloidosis, myeloma, sickle cell , hypercalcemia, hypokalemia, Lithium
Symptoms of diabetes insipidus and method of diagnosis
High volume urine output, thirst, volume depleted state, hypernatremia, if hypernatremia is severe the. CNS symptoms of confusion, disorientation, seizure, coma and death may occur.
Diagnosis: serum hypernatremia, low osmolality urine with low sodium; differentiation of central vs nephrogenic depends on response to vasopressin- central will correct with vasopressin ( decreased urine output) while there will be no response in nephrogenic DI.
Treatment for central and nephrogenic DI
Central DI: long term treatment with desmopressin
Nephrogenic DI: correct underlying problem, hydrochlorothiazide, amilioride, and prostaglandin inhibitors like NSAIDS.
Define acromegaly, what is the active hormone and causes.
Overproduction of growth hormone that increases IGF-1 which in turn leads to soft tissue overgrowth throughout the body.
Causes of acromegaly: usually a pituitary adenoma, may be part of MEN1.
Common symptoms of acromegaly
Increased hat size/ shoe/ ring size Coarsening facial features Deep voice and macroglossia Cardiomegaly and hypertension Colonic polyps and skin tags
What is the best initial test for acromegaly; what is the most accurate?
What is the treatment for acromegaly?
Patients may present with glucose intolerance and hyperlipidemia and hypertension. Prolactin levels may be elevated b/c co-secreted with GH
Best initial test is level of insulin like growth factor 1.
Most accurate test is the glucose suppression test: should see a decrease in GH With administration of glucose.
Only after laboratory identification of acromegaly should an MRI Be done.
Treatment: transphenoidal resection surgery, medications cabergoline, octreotide, pegvisomant. Radiation are for those refractory to other treatments
Hyperprolactenemia: what precursor hormone if elevated will cause the release of prolactin? What hormone is co-secreted with prolactin? What hormones will prolactin inhibit through negative feedback? What hormone inhibits prolactin secretion?
If TRH is elevated, as in hypothyroidism, prolactin will be secreted.
Prolactin is co-secreted with GH.
Prolactin causes negative feedback on LH/FSH which causes a lot of the resulting symptoms
Dopamine inhibits prolactin
What are 8 causes of hyperprolactinemia?
Prolactinoma is the most common pituitary adenoma
Pregnancy, intense exercise, hypothyroidism, acromegaly, renal insufficiench, liver failure, medications: antipsychotics, methyldopa, metocloprimide, opioids, TCA and verapamil.
Symptoms of hyperprolactinemia in men and women
Men: erectile dysfunction and decreased libido. Gynecomastia.
Women: galactorhrea, ammenorhea, infertility
Diagnostic tests for hyperprolactinemia
Serum prolactin high
Then test for: pregnancy, TFT, BUN/creat, LFT and check medication list
If all secondary causes are found tone negative then and MRI should be done.
Treatment for hyperprolactinemia
Dopamine agonists: cabergoline and bromocriptine
Transphenoidal surgery if meds do not work
Radiation is rare
