Pontine lesion in hyperglycemic crises: Relevance to osmotic demyelination syndrome and posterior reversible encephalopathy syndrome.

We herein describe a case of type 1 diabetes that presented with a pontine lesion during two hyperglycemic crises accompanied by marked fluctuations in serum osmotic pressure and blood pressure. Magnetic resonance imaging showed swollen pons with osmotic demyelination syndrome characteristics accompanying cytotoxic edema at the first crisis. The involvement of vasogenic edema was also assumed in the second crisis. Neurological symptoms were milder than magnetic resonance imaging findings. The patient recovered after 7 days without sequelae in both crises. Based on these findings, a pontine lesion needs to be considered in patients with poorly controlled diabetes showing rapid metabolic and blood pressure changes, as observed in hyperglycemic crises. Cytotoxic edema leading to osmotic demyelination syndrome and vasogenic edema caused by vascular endothelial cell damage might both be involved in the pathogenesis of a pontine lesion.