Blood-brain barrier disruption is involved in seizure and hemianopsia in nonketotic hyperglycemia

Nonketotic hyperglycemia (NKH) is a clinical syndrome consisting of severe hyperglycemia, hyperosmolarity, and intracellular dehydration without ketoacidosis. Diverse neurologic symptoms have been described in patients with NKH, including hemichorea, seizure, hemianopsia, and coma, but the pathogenic explanation for these neurologic symptoms remains unclear.

A 65-year-old female with poorly controlled diabetes presented with intermittent jerky movements in the left arm and blurred vision in the left visual field of both eyes. She was diagnosed as NKH on laboratory analysis. Focal cortical hyperintensity and subcortical hypointensity around the right parietal area was noted on T2-weighted and fluid-attenuated inversion recovery (FLAIR) magnetic resonance images. After intravenous gadolinium enhancement, minimal overlying cerebrospinal fluid (CSF) space enhancement around the right parietal area was noted. Delayed FLAIR images, obtained 12 hours later without additional gadolinium, showed prominent CSF space enhancement without parenchymal changes. Delayed gadolinium enhancement of the CSF space on FLAIR imaging was resolved in parallel to clinical improvement during the 2 months' follow-up.

Delayed gadolinium enhancement was first observed in patients with acute infarction who underwent thrombolytic therapy, and it has been considered a marker of blood-brain barrier (BBB) disruption associated with reperfusion injury. Considering that increased BBB permeability is an important mechanism for neurologic complications in diabetes, and BBB leakage occurs during epileptogenesis and contributes to the progression of epilepsy in the chronic phase, we suggest that seizures in NKH patients may be a consequence of, or at minimum have an association with, hyperglycemia-induced BBB disruption.