Gitelman Syndrome Presenting With Syncope and Treatment-Refractory Hypokalemia in A Young Woman: A Case Report.

Gitelman syndrome (GS) is a rare autosomal recessive tubulopathy characterized by hypokalemic metabolic alkalosis, hypomagnesemia, and hypocalciuria. A 27-year-old woman presented with a witnessed syncopal episode, progressive weakness, and nausea. She reported a 3-year history of muscle cramps, paresthesias, salt craving, and nocturia, with only transient correction of hypokalemia despite supplementation. Examination showed orthostatic hypotension and proximal muscle weakness, and ECG revealed flattened T and prominent U waves. Laboratory tests demonstrated severe hypokalemia (2.7 mmol/L), metabolic alkalosis, hypomagnesemia, renal potassium wasting, hypocalciuria, elevated renin and aldosterone, and a negative diuretic screen, consistent with GS. Severe hypokalemia is arrhythmogenic; ECG changes and syncope in this patient prompted monitored cardiac care and urgent correction. She was treated with intravenous and oral potassium and magnesium plus amiloride, leading to symptomatic improvement but persistently low-normal potassium levels (3.3-3.7 mmol/L). Genetic testing confirmed a pathogenic SLC12A3 variant. This case underscores the importance of considering GS in young adults with unexplained hypokalemia and the difficulty of achieving full biochemical correction despite optimal therapy.