Central pontine myelinolysis secondary to glycemic variability in type 1 diabetes: a case report and a systematic review of the literature

Central pontine myelinolysis (CPM) is a rare manifestation of osmotic demyelination syndrome (ODS) which involves the pons and causes significant morbidity and mortality. CPM usually occurs in the setting of rapid correction of severe chronic hyponatremia. A rare case of CPM due to hyperglycemia in a 27-year-old man with type 1 diabetes is reported. During the patient’s hospitalization, his plasma glucose level showed a wide variability ranging from 38 mg/dL to 530 mg/dL; while plasma sodium level was constantly normal. At computed tomography (CT) scans, areas of hypodensity with a hyperdense ring were identified in the anterior part of the pons. At magnetic resonance imaging (MRI) scan, pontine abnormalities compatible with CPM were observed. According to laboratory tests, we concluded that CPM resulted from rapid and wide shifts in osmolar gradient owing to variability in plasma glucose levels. While universally recognized in several clinical settings, CPM is rarely observed in diabetic patients. Our report supports the notion that hyperosmolarity per se plays a key role in the pathogenesis of CPM, which may occur independently of sodium abnormalities.