Normal pressure hydrocephalus in diabetic patients with recurrent episodes of hypoglycemic coma

The pathophysiology of brain damage induced by severe hypoglycemia is still unknown. We experienced a case with type 1 diabetes and recurrent severe hypoglycemic coma who showed a central brain atrophy and an abnormal cerebrospinal fluid flow, suggesting normal pressure hydrocephalus. Following this case, the CSF flow was studied using 111In-DTPA cisternography in six consecutive diabetic patients admitted for repeated episodes of hypoglycemic coma. All the patients showed the central brain atrophy on computed tomography and four of them (67%) had the ventricular reflux, with delayed clearance of 111In-DTPA. Two patients with abnormal CSF flow showed cognitive dysfunction by WAIS or WAIS-R. In contrast, none of five randomly selected diabetic patients, without hypoglycemic coma showed abnormal CSF flow. Our results suggest the presence of normal pressure hydrocephalus in diabetic patients with recurrent hypoglycemic coma. It may associate with the cognitive dysfunction.