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Flashcards in Potassium disorders Deck (20)
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0

What is normal serum potassium concentration?

4-5 mEq/L

1

What are some EKG changes of hypokalemia?

PR prolongation
ST depression
T wave flattening/inversion
U wave elevation
QRS widening

2

What are some EKG changes to hyperkalemia?

PR interval elongation
T wave elevation
Widened QRS

3

What effect does calcium concentration have on hyperkalemia?

Increased calcium increases threshold potential, decreases effects of hyperkalemia

4

What does hyperkalemia do to the threshold potential?

Decreases it

5

What does metabolic acidosis do to serum potassium concentration?

Causes hyperkalemia as H+ is buffered into the cell and K+ is pumped out

6

What does digoxin do to serum potassium levels?

Causes hypokalemia

7

What is the effect of insulin and catecholamines on serum potassium levels?

Lower the levels as potassium gets shunted into cells

8

What protein do insulin and catecholamines increase the activity of, effecting the potassium levels?

Na/K ATPase

9

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

10

What are six broad categories of hypokalemia causes?

Decreased dietary intake
Increased entry into cells
Increased GI losses
Increased urinary losses
Increased sweating
Dialysis

11

What are the three main causes of cellular intake induced hypokalemia?

Metabolic acidosis
Hyperinsulinemia
Increased catecholamine/beta agonist levels

12

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)
Hypermagnesemia

13

What are some major complications of hypokalemia?

Rhabdomyolysis
Muscle cramps/weakness
Arrhythmias
Renal disfunction
Hypertension

14

What are some causes of hyperkalemia?

Increased intake
Shift from cells to serum
Decreased urinary excretion

15

Under what situations is hyperkalemia induced by cellular shunting?

Muscle breakdown
Insulin deficiency with hyperglycemia
Metabolic acidosis

16

What are the main causes of hyperkalemia via decreased urinary excretion?

Kidney failure
Circulating volume depletion
Hypoaldosteronism

17

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+

18

How do you induce shift of K+ into cells?

Insulin/catecholamine injection
Concentration gradient (glucose)
HCO3

19

How do you remove excess K+?

Diuretics
Kayexylate
Dialysis