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STEP I 2014 > Endocrine > Flashcards

Flashcards in Endocrine Deck (53):

why can gigantism therapy lead to hypothyroidism?

somatostatin inhibits both GH and TSH (watch out for hypothyroidism when treating gigantism)


cutting stalk of pituitary stalk causes increase in which hormone levels? not prolactin or oxytocin because?

prolactin and oxytocin will be secreted by hypothalamus at normal levels not increased levels

however, prolactin release is under negative control by dopamine which is produces in hypothalamus and transported to pituitary lactrotroph cells-cutting the stalk removes this inhibition and prolactin levels increase


describe Kimmelstiel-Wilson nodule-structure, location, disease

ovoid, PAS-positive, hyaline masses. found in mesangial core at edge of glomerulus
seen in diabetes glomerulosclerosis


effect of glucagon, Epi, and glucocorticoids on glycogen synthesis?

glucagon and Epi (catabolic) both increase glycogen phosphorylase activity, increasing glycogenolysis
glucagon also inhbits glycogen synthase, promoting glycogenolysis
glucagon works in liver and epi works on muscle and adipose tissue and liver
glucocorticoids (anabolic) act in liver to increase glycogen synthesis and accumulation


Grave's disease-def, clinical symptoms, levels of rT3, T4 and TSH, and radioactive iodine uptake

thyroid-stimulating immunoglobins results in excessive movement of thyroglobin from colloid into plasma.
-thyroglobin bind iodine and produces thyroxine (T3)
-rT3 and T4 and radioactive iodine uptake are increased
-TSH is decreased


hypothyroidism-clinical features

dry skins, brittle hari, hair loss, weight gain, fatigue, and cold intolerance


Hashimoto disease-def, thyroid gland description, TSH, T4 levels

-autoimmune disorder that leads to hypothyroidism, elevated levels of anti-thyroid peroxidase (TPO) and antithyroglobulin antibodies
-gland is enlarged and uniformly firm (from chronic inflammation)
-elevated TSH and reduced T4 levels


name 2 examples of ketoacids

3-hydroxybutyrate, acetoacetate


acetoacetate:3-hydroxybutyrate ratio

decreases in diabetes and alcoholism because 3-hydrox increases


suspect pseudohypoparathyroidism when? levels of serum ca2+ phosphate, PTH. defined as

mentally retarded child with shorten metacarpals
-low CA2+, high phosphate, high PTH
-due to end-organ insensitivity to PTH, can be caused by decreased expression of Gs in RBCs-leads to decreased cAMP expression


why is Acetly-Coa carboxylase activated by hepatocytes response to insulin? why not increased activity of hexokinase?

Acetyl-CoA carboxylase catalyzes the rate-limiting step in fatty biosynthesis and is activated by insulin
hexokinase is not found in liver cells (glucokinase is) nor is it regulated by insulin. instead glucokinase gene expression is increased with hyperinsulinemia


role of glucokinase when a pt has high insulin serum levels and low glucose levels

mutated glucokinase has a higher affinity for glucose and coverts glucose to glucose-6-phosphate trapping it in the hepatocytes. other cells are unable to utilize glucose (i.e.) pancreas and insulin is up regulated in order to increase uptake of more glucose in blood.


urinary sodium levels in SIADH? why?

serum sodium levels are low b/c of increase water reabsorption. also increase volume inhibits release of renin from kidneys, decreasing action of aldosterone and increase urine sodium


name the hormones released in a cyclic manner- which one depends on suprachiasmatic nucleus

TSH, GH, prolactin (rely on sleep patterns more than light and darkness) and LH (linked to pulsatile manner of GnRH which does not rely on suprchiasmatic nucleus)
ACTH relies on circadian clock


describe three different types of hypothyroidism and effect of TRH injection test on TSH levels

hypothalamic hypothyroidism- slightly increase TSH response, but slower and
pituitary-no response
primary-exaggerated response, TSH levels are already high b/c of low thyroid hormone


diffuse nontoxic goiter has similar histology

multinodular goiter, just not as nodular


thyroid adenoma aka

thyroid (follicular) adenoma
histo-similar to normal thyroid gland, benign colloid follicles
resected b/c could become cancerous


best initial test to perform in order to evaluate thyroid function

TSH levels


if pt has hyperpigmented skin and mucous membranes then which level of adrenocortical insufficiency is it?

hyperpigmentation indicates high levels of ACTH to it's most likely primary (ie. Addison's disease) b/c the pit is responding to low levels of cortisol


medullary carcinoma produces what hormone this can be converted to what? what neuroendocrine disorders are they associated with?

calcitonin, can be converted to amyloid
-associated with MEN 2a and MEN 2b


most common type of pituitary adenoma

prolactin, produces galactorrhea


thyroid surgery can cause risk of what other endocrine gland? describe down stream effects of it's hormone

-parathyroid hormone
-PTh activates 1-hydroxlyase in the kideny which converts 25-hydroxyvitamin D3 to 1,25 dihydroxyvitamin D3.
-1,25dihydroxyvitamin D3 promotes insteastinal absorption of Ca2+ and phosphate by controlling the expression fo the calcium transporters in the intestines


type I hypersensitivity- mediated by? mech? result?

IgE-mediated. immediate or allergy. caused by crosslinking of IgE bound to mast cells resulting in their degranulation and tissue damage. immediate response to allergen


type II cytotoxic-mediated by what molecule? activates? result?

autoantibodies bind to specific tissues or cells, activate complement and cause destruction of underlying tissue


type II noncytotoxic hypersen- mediated by, mech, result. give example

autotantibodies bind to receptor stimulate function and cause eventual exhaustion of organ function (i.e Grave's disease-hyperthyrodism to hypothyroidism)


type III hypersensitivity-aka, mediators activate what? system or organ damage?

aka immune complex hypersens. caused by deposition of complexes of antigen and antibody, causing complement activation in small vasculature. system wide vs organ specific


type IV hypersen-aka, mediators (2), timing, example

aka, T-cell mediated, or delayed type. mediated by TH1 cells and macrophages. occurs 48-72hrs after exposure to protein antigens. (i.e Hashimoto thyroiditis)


pancreas releases what from:
ancinar cells
G cell
name diseases associated with each one

-main exocrine gland, digestive enzymes (amylase and lipase)
-glucagon (hyperglycemia)
-insulin (hypoglycemia)
-somatostatin (Diabetes, steatorrhea)
-gastrin (Zollinger-Ellison Syndrome)


effect of TSH on GH release

stimulates it's release from anterior pituitary


how does 11beta hydroslyase effects mineralocorticoid vs glucocorticoid levels.

increases 11-deoxycortcosterone (is a mineralocorticoid that acts like aldosterone not a glucocorticoid that acts like cortisol). glucocorticoid levels are always low.


calcium sensing receptor- produced from which gene, role, found where, disease if sensitivity is decreased (characterized by- 3 things)

-CaSR gene on chromosome 3q
-mediates feedback inhibition of secretion of parathyroid by blood CA2+ concentration
-also found in kidney, mediated ca-stimulated feedback inhibition of PTH hormone-independent ca2+ reabsorption
-familial hypocalcuric hypercalcemia-hypercalcemia, relative hypocalciuria, and normal/high levels of PTH


gene mutation and relation to PTH endocrine disorders:
-Cyclin D gene inversion
-AIRE mutation
-GCM2 mutation
-tyrosine receptor RET

-sporadic parathyroid adenomas
-autoimmune hypoparathyroidism
-autosomal recessive form of familial isolate hypoPTH
-MEN type II


presence of Psammoma bodies in an endocrine disorder

papillary carcinoma of thyroid


name 3 major contraindications of acetalozamide

pts with
-electrolyte imbalances (hypokalemia, hyponatremia, or hypercalemia)
-acid/base distrubances (metabolic acidosis or DKA)
-adrenal insuffiencey


how are pheochromocytomas diagnosed

24-hr urine for vanillylmandelic acid and metanephrines- both metabolites of NE


bence-jones protein-def, associated with which disease

- myeloma light chains detected in urine
-marker for multiple myelomas


octerotide is an analog for

somatostatin- used to manage acromegaly


role of endorphins and enkephalins on GH

both stimulate GH


hormone that has orexigenic activity

orexigenic- appetite stimulating-ghrelin


methimazole-similar to, treats, mech, serious side effect and early signs, therapy to treat side effect

-anti-thryoid drug similar to proplthiouracil; treat hyperthyroidism
-interferes with incorporation of iodine into tyrosyl residues of thyroglobulin and inhibits coupling of iodotyrosyl residues to form iodothyrglobulin
-agranulocytosis, early signs- fever, and sore throat
-discontinue drug and give granulocyte-stimulating factor


Nelson Syndrome

-excessive hyperpigmentation from excessive ACTH from pituitary adenoma


symptoms of excessive aldosterone vs adrenal insufficiency-name diseaeses

-Conn syndrome (hyperALDO)- hypertension, hypernatremia, and hypokalemia
-Addison ( adrenal insufficiency) hypotension and weakness, increased skin pigmentation, and hyperkalemia


antibodies present in type 1 diabetes

antibodies against glutamic acid decarboxylase (enzyme present in beta cells)


breast mass size required for fine-needle aspiration

greater than 4cm in post-pubertal pt


cinacalet-def, mech, uses (2)

calcimimetic agent that increases sensitivity of parathyroid calcium-sensing receptor to Ca2+ leading to a reduction in PTH
-used to manage sencondary hyperPTH in pt wih chronic renal dz and treat hyperCa2+ in pt with parathyroid cancer


relationship b/t phosphate and Ca2+

they tend to precipate together. too much phosphate can lead to hypoCa2+


cretinism-develops from, symps, can't produce, role of mother

infantile hypothyroidism,
appears normal at first and then develops feeding problems, somnolence, constipation, and failure to thrive.
-maternal-fetal transfer of T4 initially mask the condition


complications of diabetes dugs:

-pain at site of injection and hyperglycemia
-lactic acidosis (increased anion gap acidosis)
-abdominal discomfort and flatulence
-hypoglycemian, nausea and vomiting


calculate anion gap

Na+ - (Cl- +HCO3-)
normal 10-12


pentagrin-stimulate calcitonin secretion is a maker for vs serum gastrin

medullary carcinoma of thyroid a component of MEN IIa
-marker for pancreatic and duodenal endocrine tumors send in MEN I, they also secrete insulin or glucagon



both have parathyroid hyperplasia
big clue is mutliple angiofibromas and or lipomas seen in MEN I pts

MEN I- pituitary, parathyroid, and pancreas
MEN IIa-parathyroid, pheo, and medullary thyroid carcinoma


triiodothyronine aka



if coritsol is increased but MRI brain scan is normal-pt has, levels of CRH and ACTH

then pt has primary hypercortisolism of adrenal orgrin
ACTH and CRH are decreased due to feedback mechanism