Epileptic Manifestations, Pathophysiology and Imaging Characteristics of Non-Ketotic Hyperglycaemia: A Report of One Case with Irreversible Homonomous Hemianopia

Abstract

Background: Focal seizures related to non-ketotic hyperglycemia (NKH) are rare in clinical practice. Plasma glucose levels are usually above 16.6 mmol/L and with normal or slightly elevated serum osmolality. The occurrence of focal seizures may be augmented by the absence of ketoacidosis. Electroencephalogram (EEG) during seizures usually confirms the diagnosis, however, the absence of epileptiform discharges does not rule out seizures. A non-ketotic hyperglycemiaassociated occipital lobe seizure can manifest itself as color flashes, blurry vision with periodic confusion, and usually resolves with insulin treatment and rehydration. Recently, seizures associated with nonketotic hyperglycemia have been found to be associated with subcortical T2 hypointensity on magnetic resonance imaging, especially in the occipital lobes. However, the mechanism remains unclear, although iron accumulation is suggested.

Case Presentation: We present a case 41- year-old male patient who presented headache, left-sided visual disturbances in the form of seeing round, colored flickering lights with left homonymous hemianopia and occipital lobe seizures associated with nonketotic hyperglycemia found to have a blood glucose of 18 mmol/L with a normal anion gap of 10 and calculated serum osmolality of 303 mOsm/L. Magnetic resonance imaging (MRI) brain showed subcortical T2 and flair hypointensity due to iron accumulation .The patient’s visual disturbances and seizures responded to rehydration and insulin treatment.

Conclusion: In conclusion, nonketotic hyperglycemia can be associated with occipital lobe seizures supporting the role of iron accumulation as a mechanism for subcortical T2 hypointensity in magnetic resonance imaging. Hyperglycemia should be taken into consideration when making an etiologic diagnosis of homonymous hemianopia.