Adult-Onset Bartter Syndrome Presenting as Refractory Hypokalemia and Metabolic Alkalosis: A Case Report.

Bartter syndrome (BS) is a rare autosomal recessive salt-wasting tubulopathy characterized by hypokalemic metabolic alkalosis, hyperreninemia, and hyperaldosteronism without hypertension. It usually presents in childhood; however, adult-onset cases are infrequent and often misdiagnosed. We report a young adult male from Pakistan with congenital deaf-mutism who presented with vomiting, irritability, and altered sensorium. Laboratory findings revealed persistent hypokalemia, metabolic alkalosis, and acute kidney injury secondary to sepsis. Despite adequate potassium replacement, hypokalemia persisted, prompting evaluation for a renal potassium-wasting disorder. Further investigations showed elevated urinary sodium, potassium, and chloride with normal magnesium and a normal-to-high urinary calcium-to-creatinine ratio, consistent with Bartter syndrome. The patient was managed with intravenous fluids, antibiotics, and potassium supplementation, followed by the addition of oral potassium chloride and spironolactone. Clinical and biochemical improvement was noted, with normalization of renal function and serum electrolytes at discharge and on follow-up. This case underscores the diagnostic importance of considering Bartter syndrome in adults with refractory hypokalemia and metabolic alkalosis, particularly after excluding more common causes such as vomiting or diuretic abuse. The coexistence of chronic hypotension and prior myocardial infarction highlights the potential cardiovascular implications of chronic hypokalemia. Bartter syndrome may present in adulthood with atypical features. Early recognition through targeted biochemical evaluation and timely initiation of potassium-sparing therapy are crucial for favorable outcomes and prevention of renal and cardiovascular complications, especially in resource-limited settings lacking genetic diagnostic facilities.