Lethal hyperkalemia associated with severe hyperglycemia in diabetic patients with renal failure.

Two patients with diabetic nephropathy on maintenance hemodialysis developed extreme hyperkalemia (7.9 and 9.3 mmol/L, respectively) in association with severe episodes of hyperglycemia (1,152 and 1,185 mg/dL, respectively). The increase in serum potassium was out of proportion to the degree of metabolic acidosis that both patients had, and no exogenous source of hyperkalemia could be identified. Despite treatment efforts both patients died shortly after arrival as a consequence of cardiac arrest. It is proposed that the hyperosmolality of extracellular fluid produced by severe hyperglycemia drives potassium passively out of the cells, therefore favoring the rapid development of hyperkalemia. Insulin deficiency could also play a role. This situation is particularly dangerous in individuals with impaired renal function. Adequate blood glucose control in diabetic patients on dialysis is important to avoid life-threatening hyperkalemia.