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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