Hyponatremia and hyperkalemia associated with peritoneal effusion in four cats

Peritoneal effusions may cause concurrent hyponatremia and hyperkalemia in cats.) Hyponatremia and hyperkalemia may develop despite normal adrenal gland func tion. Recognition of effusive states as a cause of hyponatremia and hyperkalemia is important to avoid an incorrect diagnosis of hypoadrenocorticism and to avoid unnecessary ancillary tests.