Overview
Definition
A group of autosomal recessive renal tubular disorders characterized by hypokalemic metabolic alkalosis, hypercalciuria, and normal/low blood pressure, mimicking loop diuretic action.
Epidemiology
Rare, often presents in utero (polyhydramnios) or in early infancy.
Etiology & Risk Factors
- Genetic mutations in genes encoding loop-sensitive cotransporters (NKCC2, ROMK, CLCNKB) in the thick ascending limb of loop of Henle
Clinical Symptoms
- Severe polyuria and polydipsia
- Growth retardation and failure to thrive
- Dehydration episodes
- Muscle weakness
Clinical Approach
Diagnosis
- Hypokalemia and metabolic alkalosis
- Hypercalciuria (causing nephrocalcinosis)
- Elevated urinary chloride excretion
- Markedly elevated renin and aldosterone
Management
- Aggressive potassium and fluid replacement
- NSAIDs (Indomethacin) to block prostaglandins and reduce GFR/polyuria
- Potassium-sparing diuretics
Complications
- Nephrocalcinosis / Chronic Kidney Disease
- Severe dehydration and electrolyte shock
- Hearing loss (in Type IV Bartter)