Glucose-induced hyperkalaemia: A hazard for diabetics?

The intravenous injection of glucose as a "therapeutic test" in comatose diabetics is reviewed in the light of evidence that it may evoke a paradoxical rise in plasma-potassium in the insulin-deprived diabetic. The plasma-potassium rose promptly after a drink of 50 g glucose in 8 insulin-dependent diabetics who had not had insulin for approximately 14-26 hours. This rise coincided with a rise in plasma-osmolality. In non-diabetic controls, however, plasma-potassium fell after the glucose drink. Osmotic and hormonal mechanisms may account for the rise in plasma-potassium in the diabetics. Since the rise in plasma-potassium may be clinically important, caution with, or abandonment of, the use of intravenous glucose as a therapeutic test is recommended.