Cerebral edema and ophthalmoplegia reversed by mannitol in a new case of insulin-dependent diabetes mellitus.

Cerebral edema is a sometimes fatal complication of diabetic ketoacidosis which occurs unpredictably and when biochemical parameters show improvement. A case of a young, newly diagnosed insulin-dependent diabetic boy who developed this complication while receiving a low-dose continuous insulin infusion is reported. Two hours after treatment signs of headache, ophthalmoplegia, and blurred disc margins suggested early cerebral edema. Despite fluid restriction, avoidance of alkali, and phosphate supplementation, cerebral edema ensued three hours later. This complication was then reversed by administration of mannitol. Our patient's ophthalmoplegia, unlike typical diabetic ophthalmoplegia, improved immediately and completely resolved within two weeks after this episode. It is concluded that the use of mannitol in the cerebral edema of diabetic ketoacidosis is beneficial if it is instituted promptly.