食塩制限時の高K血症

Abstract

Hyperkalemia (≧5 mEq/1) is an electrolyte imbalance that is sometimes encountered even in patients who have normal renal function. We report two patients with acute myocardial infarction who exhibited hyperkalemia during salt restriction and discuss the pathophysiology of hyperkalemia in these patients. The first patient, a 62-year-old woman, showed normal PRA (plasma renin activity) and PAC (plasma aldosterone concentration) responses to a furosemide-standing test, and a renal biopsy specimen revealed a tubulo-interstitial lesion. Therefore, the hyperkalemia in this case seemed to be due to hyporeaction of the distal tubules to aldosterone. In contrast, the second patient, a 65-year-old woman, had poor PRA and PAC responses to the furosemide-standing test, and renal histology revealed a small tubulo-interstitial lesion. The hyperkalemia in the second case was thought to be due to hyporeninemic hypoaldosteronism. Based on these findings, PRA, PAC and tubulo-interstitial lesions should be studied in more detail in patients with hyperkalemia during salt restriction.