A 2 month old girl has failure to thrive, polyuria and medullary nephrocalcinosis affecting both kidneys. Investigations show blood pH 7.48, bicarbonate 25 mEq/l, potassium 2 mEq/l, sodium 126 mEq/l and chloride 88 mEq/l. The most likely diagnosis is –
Correct Answer: Bartter syndrome
Description: Clinical features of the infant --> Polyuria, Growth retardation, Medullary Nephrocalcinosis Electrolyte abnormalities: -
Decreased potassium (Normal 3.5 — 5.0 meq/L) o Normal Bicarbonate (Normal 21-30 meq/L)
Decreased sodium (Normal 136 — 145 ineq/L) o Increased pH (Normal 7.38 — 7.44 meq/L)
Decreased Chloride (Normal 98 — 106 meq/L)
C/F and electrolyte abnormalities in Bartter's syndrome
a Hypokalemia o Polyurea and Nocturea (d/t hypokalemia)
Metabolic alkalosis ❑ Increased urinary chloride (cause Hypochloremia)
Normal to low blood pressure o Hypomagnesemia (seen in minority of patient)
Growth retardation o Hypercalciurea (causes nephrocalcinosis which is visible on ultrasound) Other options
Distal renal tubular acidosis - It can be easily ruled out as it causes acidosis not alkalosis
Primary hyperaldosteronism - In primary hyperaldosteronism, Sodium level is always increased and the B.F. is high.
Pseudo hypoaldosteronism - Aldosterone level is normal or increased but there are features of aldosterone deficiency such as decreased sodium and increased potassium.
Category:
Pediatrics
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