Epileptic manifestations, pathophysiology, and imaging characteristics of non-ketotic hyperglycaemia: a review of the literature and a report of two cases with irreversible cortical vision loss

Non-ketotic Hyperglycemia Presenting as Focal Status Epilepticus and Subsequent Todd's Paralysis

Uncontrolled diabetes can result in many neurological and non-neurological complications. It's common for hypoglycemia to present as a seizure; however, in cases of hyperglycemia, especially in the absence of ketones, seizures are uncommon. Here, we present a case of a 75-year-old female with no prior history of epilepsy disorder presenting as focal status epilepticus complicated by Todd's paralysis. We are describing the case with a review of the current literature.

Neuroimaging features in a patient with non-ketotic hyperglycaemic seizures: A case report

BACKGROUND

Non-ketotic hyperglycaemic (NKH) seizures are a rare neurological complication of diabetes caused by hyperglycaemia in non-ketotic and non-hyperosmotic states. The clinical characteristics of NKH seizures are atypical and lack unified diagnostic criteria, leading to potential misdiagnoses in the early stages of the disease.

CASE SUMMARY

This report presents a rare case of NKH seizures in a 52-year-old male patient with a history of type 2 diabetes mellitus. We performed comprehensive magnetic resonance imaging (MRI) studies at admission, 12 d post-admission, and 20 d post-discharge. The imaging techniques included contrast-enhanced head MRI, T2-weighted imaging (T2WI), fluid-attenuated inversion recovery (FLAIR), diffusion-weighted imaging, susceptibility-weighted imaging, magnetic resonance spectroscopy (MRS), and magnetic resonance venography. At the time of admission, T2WI and FLAIR of the cranial MRI showed that the left parieto-occipital cortex had gyrus-like swelling and high signal, and subcortical stripes had low signal. MRS showed a reduced N-acetylaspartate peak and increased creatine and choline peaks in the affected areas. A follow-up MRI 20 d later showed that the swelling and high signal of the left parieto-occipital cortex had disappeared, and the low signal of the subcortex had disappeared.

CONCLUSION

This case study provides valuable insights into the potential pathogenesis, diagnosis, and treatment of NKH seizures. The comprehensive MRI findings highlight the potential utility of various MRI sequences in diagnosing and characterizing NKH seizures.

GM3 synthase deficiency increases brain glucose metabolism in mice

GM3 synthase (GM3S) deficiency is a rare neurodevelopmental disorder caused by an inability to synthesize gangliosides, for which there is currently no treatment. Gangliosides are brain-enriched, plasma membrane glycosphingolipids with poorly understood biological functions related to cell adhesion, growth, and receptor-mediated signal transduction. Here, we investigated the effects of GM3S deficiency on metabolism and mitochondrial function in a mouse model. By indirect calorimetry, GM3S knockout mice exhibited increased whole-body respiration and an increased reliance upon carbohydrate as an energy source. 18F-FDG PET confirmed higher brain glucose uptake in knockout mice, and GM3S deficient N41 neuronal cells showed higher glucose utilization in vitro. Brain mitochondria from knockout mice respired at a higher rate on Complex I substrates including pyruvate. This appeared to be due to higher expression of pyruvate dehydrogenase (PDH) and lower phosphorylation of PDH, which would favor pyruvate entry into the mitochondrial TCA cycle. Finally, it was observed that blocking glucose metabolism with the glycolysis inhibitor 2-deoxyglucose reduced seizure intensity in GM3S knockout mice following administration of kainate. In conclusion, GM3S deficiency may be associated with a hypermetabolic phenotype that could promote seizure activity.