Hypokalemia

Kidney potassium loss

• Excess mineralocorticoid activity

  • Mineralocorticoid disorder

  • Renal artery stenosis

  • Liddle's syndrome

• Potassium-wasting diuretics

  • Loop diuretics

  • Thiazide diuretics

• Tubulopathy

  • Bartter syndrome, Gitelman syndrome

  • Fanconi syndrome

  • Potassium wasting due to hypomagnesemia

Gastrointestinal (GI) potassium loss

• Diarrhea

  • Laxative abuse

• Vomiting

  • Nasogastric/orogastric (NG/OG) suction

Intracellular shifts (movement of potassium into cells)

• Alkalosis

• Insulin

• β-agonists (e.g., albuterol)

• Hypokalemic periodic paralysis (PP, hypoKPP, hypoPP)

• Usually asymptomatic

• Muscle cramps, weakness

• Cardiac arrhythmias (esp., ventricular tachycardia, ventricular fibrillation)

• Can decrease ability to concentrate urine

• If hypertension present, consider evaluation for mineralocorticoid disorder, renal artery stenosis, Liddle's syndrome, etc.

• Laboratory workup:

  • Evaluate for other electrolyte derangements, esp. hypomagnesemia

  • Alkalosis

• EKG if severe (consider if <2.5 mEq/L, esp. if <2 mEq/L)

• Treat underlying cause

• Oral potassium chloride replacement is easiest and safest for mild hypokalemia (3-3.5 mEq/L)

• IV repletion for severe/symptomatic or if unable to tolerate PO