A Diagnostic Blind Spot in Pseudo-Bartter Syndrome: Aberrant Renin-angiotensin-aldosterone System Activation from Focal Renal Scarring.

A 40-year-old woman presented with intermittent limb weakness, edema, and persistent hypokalemia. She had a history of recurrent urinary tract infections, but no diuretic or laxative use. Laboratory findings revealed metabolic alkalosis with elevated plasma renin activity and aldosterone levels. The urinary electrolyte response to fluid administration suggested pseudo-Bartter syndrome due to the volume depletion. Abdominal imaging revealed renal scarring, suggesting focal renin release from the ischemic regions. This case highlights the importance of recognizing secondary systemic renin-angiotensin-aldosterone system (RAAS) activation driven by focal renin release in renal scarring. This also illustrates a paradox in which salt and water restriction may worsen RAAS-driven hypokalemia.