REN and Hypokalemia: Blood tests showed hypokalemia (2.0 mmol/L), hypomagnesemia (0.55 mmol/L), hypocalciuria (2.0 mmol/24 h), and renin–angiotensin–aldosterone system (RAAS) activation (renin 49.6 mIU/L, aldosterone 740 pmol/L), metabolic alkalosis, normal renal function, and no proteinuria.