Flashcards in Potassium disorders Deck (20)
What is normal serum potassium concentration?
What are some EKG changes of hypokalemia?
T wave flattening/inversion
U wave elevation
What are some EKG changes to hyperkalemia?
PR interval elongation
T wave elevation
What effect does calcium concentration have on hyperkalemia?
Increased calcium increases threshold potential, decreases effects of hyperkalemia
What does hyperkalemia do to the threshold potential?
What does metabolic acidosis do to serum potassium concentration?
Causes hyperkalemia as H+ is buffered into the cell and K+ is pumped out
What does digoxin do to serum potassium levels?
What is the effect of insulin and catecholamines on serum potassium levels?
Lower the levels as potassium gets shunted into cells
What protein do insulin and catecholamines increase the activity of, effecting the potassium levels?
What does aldosterone do to potassium levels?
Decreases them by upregulating BK and ROMK channels in the collecting tubule, at the same time upregulating NaK ATPase on the basolateral side
What are six broad categories of hypokalemia causes?
Decreased dietary intake
Increased entry into cells
Increased GI losses
Increased urinary losses
What are the three main causes of cellular intake induced hypokalemia?
Increased catecholamine/beta agonist levels
What are four ways in which urinary losses can lead to hypokalemia
Increased distal tubule flow (diuretics, salt-wasting nephropathy, polydipsia)
Hypercalcemia (increased distal flow)
Mineralocortocoid excess (increased aldosterone levels)
What are some major complications of hypokalemia?
What are some causes of hyperkalemia?
Shift from cells to serum
Decreased urinary excretion
Under what situations is hyperkalemia induced by cellular shunting?
Insulin deficiency with hyperglycemia
What are the main causes of hyperkalemia via decreased urinary excretion?
Circulating volume depletion
What three steps should be taken to treat hyperkalemia?
1. Treat membrane (Induce hypercalcemia)
2. Shift K+ into cells
3. Get rid of excess K+
How do you induce shift of K+ into cells?
Concentration gradient (glucose)