Endocrine Flashcards
Causes of elevated CK
Hypothyroidism
Polymyositis, Dermatomyositis
Muscular dystrophies
Statins
What type of insulin given to those with DKA?
Regular insulin.
What mediates insulin resistance in overweight/obese individuals?
Serum FFA and TAG
FFA increase resistance by serine phosphorylation of insulin receptor and decrease insulin secretion.
Treatment of congenital adrenal hyperplasia.
Exogenous corticosteroids to suppress ACTH.
Central (complete vs. partial) vs. Peripheral DI
Central: > 10% rise in urine osmolality after vasopressin
Complete: > 50%
What is used to treat graves opthalmopathy and how?
Glucorticoids (PTU and methimazole do NOT help)
Opthalmopathy develops bc of edema and infiltration of lymphocytes -> stimulate retroorbital fibroblasts to secrete cytokines and produce glycosaminoglycans -> inflam and accum of glycosaminoglycans -> proptosis.
How to prevent absorption of radioactive iodide isotopes?
Administer Potassium Iodide - competitive inhibitor of the Na-iodide symporter.
What glucose transporter is responsive to insulin and where is it located?
GLUT4 - on skeletal muscle and adipocytes
How do glucocorticoids affect the liver vs. muscle/adipose tissue?
Liver - increase gluconeogenesis and glycogenesis.
Muscle/Adipose - antagonize insulin effects - proteolysis and lipolysis. to provide substrates for making glucose.
Central DI - caused by damage to what?
Paraventricular and Supraoptic nuclei of the Hypothalamus
(Post pituitary injuries don’t result in permanent central DI since the hypothalamic neurons will hypertrophy to compensate)
What causes the increased risk of gallstones in pregnant women or those on OCPs?
- Estrogen induced cholesterol hypersecretion - increases HMG CoA reductase
- Progesterone induced gallbladder hypomotility
MOA of acarbose
alpha-glucosidase inhibitors - decrease activity of dissacharidases on intestinal brush border.
What hormones are Gs?
Glucagon
TSH
PTH
cAMP -> protein kinase a.
What paraneoplastic syndrome is associated with neuroblastoma?
Opsoclonus-Myoclonus.
TNFalpha facilitates insulin resistance thru what mechanism?
Phosphorylation of serine residues.
This inhibits IRS-1 (insulin receptor substrate) tyrosine phosphorylation by insulin.
Histology of Hashimoto’s thyroiditis?
Mononuclear parenchymal infiltration with well-developed germinal center
“looks like a lymph node”
Electrolyte abnormalities in primary adrenal insufficiency?
HypoNa
HyperK
HyperCl
Non anion gap metabolic acidosis
(think like the aldo antagonist diuretics)
In a patient on chronic glucocorticoids presenting with adrenal crisis s/p surgery, what are pt’s levels of CRH, ACTH, and cortisol?
Decreased CRH, ACTH, and cortisol!
Thyroid hormone receptor is located where?
Nucleus!
What should diabetics be advised to do to protect against peripheral neuropathy?
DAILY foot inspection
(changing socks, snug shoes, testing water first, etc)
YEARLY neurologic evaluation by physician.
How are the following altered in DKA? Na K pH urine HCO3 urine H2PO4
Hyponatremic:
- osmotic activity of glucose -> Na drops 1.6 mEq/L for every 100 mg/dL rise in glucose
- hyperglycemia induced osmotic diuresis -> Na and free water losses
HyperK:
- K/H exchanger
- but total body K loss
Metabolic Acidosis: Dec. pH
Urine:
Decreased HCO3 = reabsorbed
Increased H2PO4, NH4+: increased secretion of acid buffers (due to H+ secretion from the kidneys)
Hyperglycemia, Hypovolemic
Hyperammonemia: due to muscle degradation.
Which antidiabetic drug increases GLUT4 transport to adipocytes?
Glitazones
activate PPARalpha -> increase transcription of insulin responsive genes -> GLUT4 translocation to cell membrane (adipocytes, skeletal muscle)
Mech of acarbose
alpha-glucosidase inhibitor - inhibit intestinal brush border alpha-glucosidases - dec. postprandial hyperglycemia.
Tox: GI disturbance, hepatotoxic (miglitol)
What are the GLP-1 analogs and DPP-4 inhibitors? Mech?
GLP1: exenatide, liraglutide
DPP-4 inhibitor: -gliptin (inhibit degradation of GLP1)
Mech: increase insulin, decrease glucagon release (in response to glucose, like physiologic), delay gastric emptying
Tox: (X) No hypoglycemia or weight gain (nl physiology)
- n/v
- pancreatitis
- mild urinary or resp infections
During fasting, normoglycemic with higher than normal baseline insulin levels = what?
Insulin Resistance - DM II
READ THE FUCKING GRAPHS.
Labs in PCOS
High LH, LH/FSH ratio
Low to nl FSH - bc FSH is dec. compared to LH, can’t aromatize the testos to estrogen.
HOW DOES HYPOTHALAMUS REGULATE PROLACTIN?!
Dopamine INHIBITS Prolactin.
Hypothalamic destruction => Hyperprolactin!
What is the presentation of Type I DM?
Subacute with polyuria, polydipsia, polyphagia with weight loss and fatigue.
Young adult, sometimes recent viral infection will be in picture.
Histology of medullary thyroid cancer?
Polygonal or spindle shaped cells with extracellular amyloid deposits (stain with congo red)
Glucagonoma
- Diabetes
- GI sx
- Necrolytic Migratory Erythema: erythematous papules and plaques that coalesce, leaving bronze-colored central indurated area with peripheral blistering/scarring.
Hyperthyroidism - what lab needs to be checked before treating?
PTU and Methimazole can cause agranulocytosis!!
Papillary Thyroid Carcinoma - Histo findings
Orphan Annie nuclei (Large cells with finely dispersed chromatin)
Psammoma Bodies
Inclusion bodies and nuclear grooves
Medullary Carcinoma Histo
Sheets of cells with amyloid stroma.
Metyrapone test
Blocks 11b-hydroxylase (increases 11 deoxycorticosterone but this doesn’t feedback negatively) -> dec cortisol -> increased ACTH -> increased 11 deoxycorticosterone, 17-OHS (its metabolite) if you have normal HPA axis.
Pituitary Apoplexy - presentation, tx.
Intrapituitary hemorrhage, most often in an underlying pituitary adenoma. EMERGENCY.
Sx:
Chronic sx of pituitary adenoma (h/a, decreased libido)
Acute severe headache, bitemporal hemianopsia
Signs of meningeal irritation may be seen
Will eventually develop cardio collapse due to ACTH deficiency and glucocorticoid deficiency.
Tx:
Glucocorticoids - prevent cardio collapse
Surgery to decompress.
Note: May have similarities to subarachnoid, but the hx of pit adenoma sx and acute cardiovascular collapse favor pit hemorrhage.
Polyuria and Polydipsia - what 3 things should you immediately think of?
- DM
- DI
- Psychogenic Polydipsia.
Pathophysiology of Graves Proptosis/Opthalmopathy
Lymphocytes infiltrate orbital tissue -> secrete cytokines that activate fibroblasts -> secrete increasing amounts of glycosaminoglycans/hyaluronic acid -> draws water into orbit resulting in extraocular muscle edema.
Can result in sensations of grittiness, tearing since the lids don’t cover the eyes fully.
Note: neutrophil infiltration would be in like orbital cellulitis.
