Hypokalemia Evaluation Algorithm

Before evaluating hypokalemia, life threatening complications such as arrhythmias and paralysis should be looked for. If present, it should be treated with IV potassium(K) & magnesium(Mg)
The next step in evaluating hypokalemia is differentiating kidney K wasting from other causes. 
A urine K/Cr ratio < 15 mEq/g suggests extra-renal causes
  • Laxative use
  • Diarrhea
A urine K/Cr ratio > 15 mEq/g suggests urinary losses:
  • High Blood Pressure:
    - ↑ Renin ↑ Aldosterone: Malignant HTN, Renovascular HTN, Renin secreting tumor
    - ↓ Renin ↑ Aldosterone: Primary hyper-aldosteronism
    - ↓ Renin ↓ Aldosterone: Syndrome of apparent mineralocorticoid excess, Liddle's syndrome, Congenital adrenal hyperplasia, Licorice consumption
 • Low/Normal Blood Pressure:
    - Metabolic Alkalosis: Emesis, Diuretics, Bartter syndrome, Gitelman syndrome
    - Variable: Non-reabsorbable anions - Penicillins, Hippurate
    - Metabolic acidosis: Proximal RTA, Distal RTA, DKA

Dr. Krithika Mohan @krithicism

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