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Flashcards in K+ Deck (17):
1

what is the normal plasma [K+]?

3.5-5 mEq/L

2

What hormones regualte K and what do they do?

Insulin and epinephrine (beta-2 stimulation), active Na/K ATPase

3

what are some causes of hyperkalemia?

beta-blockers (inhibits ATPase), digoxin, intense exercise, acidosis

4

ekg changes in hyper and hypokalemia

tall t, v fib, wide complex; flat t, high u

5

How is K excretion controlled?

changes in secretion (not much reabsorption change)

6

where is K reabsorbed?

65% PT, 25% TAL, CT varies

7

what is the driving force for K secretion across apical membrane and what does this mean?

chemical gradient (affected by urine flow rate) and electrical gradient (activity of ENaC)

8

what are the two key determinants of CCD secretion of K

aldosterone and Na delivery and transport

9

what are some blockers of Na channels?

Amiloride, triamterene, trimethoprim (bactrim), pentamidine

10

what are some causes of kidney hyperkalemia

decreased GFR, aldosterone deficiency, decreased Na delivery or blockage of Na channels. Also, NSAIDS and ACEI

11

what is the main stimulator for aldosterone?

AT2,K+. So ACEI can cause hyperkalemia

12

causes of aldosterone deficiency

low plasma renin

13

Depletional vs nondepletional hypokalemia

depletional- gi (vomiting, diarrhea), renal (aldosterone excess, diuretics, Bartter and Gitleman, RTA), low intake. nondep- redistribution (albuterol, ^ insulin)

14

primary vs secondary hyperaldosteronism

cause hypokalemia w/htn. Primary (tumor) has decreased renin, secondary has increased renin

15

bartters syndrome

NKCC2 mutation (K/Cl/Na channel)

16

gitelman's syndrome

Na/Cl channel mutation

17

how do you distinguish diuretics, bartters and vomiting causes of hypokalemia w/ met alk?

vomiting has a low urine Cl