Hypokalemia-induced rhabdomyolysis as the first symptom of primary aldosteronism: a case report and literature review.

Primary aldosteronism (PA) is a well-documented cause of secondary hypertension, often accompanied by hypokalemia. However, PA with normal blood pressure and hypokalemic rhabdomyolysis (RM) is rare. We report a case of hypokalemia-induced RM as the first symptom of PA. A 65-year-old woman was admitted due to intermittent limb weakness and myalgia. She denied a history of hypertension. Laboratory findings showed profound hypokalemia (1.8 mmol/L) and extreme elevation of creatinine kinase (CK) levels (18,370 U/L), suggestive of hypokalemia-induced RM. She was administered intravenous fluids as well as active oral and intravenous potassium supplements. CK and myoglobin levels gradually decreased, but the serum potassium recovery was poor. Further evaluations strongly suggested PA by an aldosterone-producing adenoma, which was surgically removed. After surgery, the patient recovered well. The systolic blood pressure decreased by approximately 10-20 mmHg and the diastolic blood pressure decreased by approximately 5-10 mmHg. After discontinuation of spironolactone and oral potassium supplementation, the patient had normal serum potassium levels. This case indicates that PA is a cause of hypokalemic RM, even in patients with normal blood pressure. In addition, attention should be paid to changes in serum aminotransferase levels associated with RM. If the patient had no liver disease, it might be a marker for skeletal muscle injury instead of hepatocyte damage.