Endocrine/Renal Flashcards
Where is EPO produced?
Peritubular cells in the kidneys with a small amount (10%) also in perisinusoidal cells of the liver.
Stimulated by hypoxia and suppressed by polycythemia –> accelerates release of erythroid precursors and reticulocytes from bone marrow
Uses include treatment of anemia, bone marrow suppression, Jehovah’s witnesses but takes several weeks to improve Hb levels
The most sensitive indicator of failing thyroid function?
Increased TSH
Difference between subclinical hypothyroidism and hypothyroidism?
FT4 is normal in subclinical hypothyroidism and low in hypothyroidsim. (TSH elevated in both).
Subclinical hypothyroidism is thought to have little or no perioperative significance. It is common in people aged 65 years or older. It is often transient and presents with minimal or nonspecific symptoms such as fatigue, depression and hyperlipidemia.
Hypothyroidism affects respiratory control mechanisms, fluid homeostasis, electrolytes particularly sodium, temperature regulation, muscle relaxation (with a higher incidence of myasthenia gravis), and increased MI risk.
Almost all hormones increase during a stress response EXCEPT?
T3/T4 and GRH are DECREASED
TSH and insulin can go up or down in response
Posterior pituatary hormones?
Vasopressin (ADH) and oxytocin - these hormones typically not altered with pituitary tumors because ANTERIOR pituitary typically involved
Normal serum osmolality?
290 mOsm/kg
Normal urine sodium?
20 mEq/L
Normal urine osmolality?
100 mOsm/kg
Treatment for diabetes insidious?
vasopressin
How to differentiate between SIADH versus cerebral salt wasting syndrome?
volume status:
SIADH is euvolemic to hypervolemic
CSW is hypOvolumic
treatment for SIADH?
fluid restriction to < 800mL/day Salt/solute intake vasopressin ANTagonists such as conivaptan, demeclocycline or lithium Hypertonic saline (reserved for severe cases)
Mnemonic for Conn’s syndrome versus Addison’s
Conn’s
imagine a cone of SALTed caramel: INCR sodium, decr potassium
Addison
imagine a cone of vanilla: DECR sodium but INCR calcium from the dairy, and incr potassium
Treatment for diabetes insipidus?
Induce an SIADH picture: give desmopressin, vasopressin or even carbamazepine (which sensitizes collecting duct to ADH)
Plasma osmolality formula
Posm = 2 * Na + [Glu/18] + BUN/2.8
FeNa, FeUrea and Urine Na in prerenal azotemia?
FeNa < 1%
FeUrea <35%
Urine Na <20
FeNa, FeUrea and Urine Na in ATN?
FeNa > 1%
FeUrea >35%
Urine Na >40
Most common changes seen in ESRD?
anemia from decreased EPO
hypOcalcemia
hypERkalemia
How does magnesium change in setting of ESRD?
increases
How does cholesterol change in setting of ESRD?
hyperlipidemia