K

Question 1

hyperkalemia definition

causes?

Answer 1

Serum potassium (K+) > 5 mEq/L.
- ↓ Excretion:
Renal insufficiency, drugs (eg, spironolactone, triamterene, amiloride, ACE inhibitors (ACEIs), trimethoprim, NSAIDs, β-blockers), hypoaldosteronism, type IV renal tubular acidosis (RTA), calcineurin inhibitors.
- Cellular shifts:
Cell lysis, tissue injury (rhabdomyolysis), tumor lysis syndrome, insulin deficiency, acidosis, drugs (eg, succinylcholine, digitalis,arginine, β-blockers), hyperosmolality, exercise, resorption of blood (hematomas, GI bleeding).
- ↑ Intake:
Food (most fruits, potatoes), iatrogenic.

Question 2

History of hyperkalemia

Answer 2

May be asymptomatic or may present with nausea, vomiting, intestinal colic,
areflexia, weakness, flaccid paralysis, arrhythmias, and paresthesia.

Question 3

ECG of hyperkalemia

Answer 3

tall, peaked T waves; a wide QRS; PR prolongation; and loss of P waves

Question 4

hyperkalemia Treatment principles

Answer 4

+++ C BIG K +++
1- Calcium gluconate
a 10% solution, 15-30mL , IV , over 2 to 5 min
if K+ > 6.5 mEq/L or ECG changes
2- Insuline (short acting)
10 unit , IV , in 20 min
+ glucose (if BG <250)
25 g (50 mL of a 50% solution)
3- Beta agonist (albuterol)
4- alkali (bicabonate)
5- Eliminate K+ from diet, medications (eg, penicillin has K+), and IV
fluids.
6- IV saline (in hypovolemic settings) and loop diuretics (in normo- or hypervolemic
settings) can enhance urinary excretion of K+.
7- Dialysis

Question 5

hypokalemia definition

causes?

Answer 5

Serum K+ < 3.6 mEq/L.

Transcellular shifts: Insulin, β2-agonists, and alkalosis
GI losses: Diarrhea, chronic laxative abuse, vomiting, nasogastric tube
suction.
Renal losses: Diuretics (eg, loop or thiazide), 1° mineralocorticoid excess
or 2° hyperaldosteronism, ↓ circulating volume (stimulates RAAS- and
mineralocorticoid-associated K+ secretion), Bartter and Gitelman syndromes,
drugs (eg, gentamicin, amphotericin), diabetic ketoacidosis, hypomagnesemia,
type I and type II RTA

Question 6

Hx and PE of hypokalemia

Answer 6

Presents with fatigue, muscle weakness or cramps, ileus, hyporeflexia, paresthesias,
rhabdomyolysis, and ascending paralysis.

Question 7

ECG in hypokalemia

Answer 7

T-wave flattening, U waves (an additional wave after the T wave), and ST-segment depression, leading to AV block and subsequent cardiac arrest.

Question 8

Treatment in hypokalemia

Answer 8

Treat the underlying disorder.
■ Oral and/or IV K+ repletion. Oral is the preferred route for safety purposes.
If IV is necessary, a continuous rate of K+ as an additive is preferred
over an IV K+ bolus. Reserve IV boluses for symptomatic hypokalemia or
ECG changes. Do not exceed 20 mEq/L/h.
■ Replace magnesium, as this deficiency makes K+ repletion more difficult.