Biochemical findings in sudden unexpected death in epilepsy: Hospital based case-control study

Purpose: A review study on the biochemistry of epilepsy showed that in epileptic patients, serum glucose and cholesterol concentrations are low, sodium is unaffected, potassium increases, glucose is high and mild hypocalcemia. We have conducted a biochemical study on sudden unexpected death in epilepsy (SUDEP) cases in an attempt to establish the characteristic biochemical values to diagnose these deaths. Methods: This was a hospital based case-control study done at All India Institute of Medical Sciences, New Delhi for one year. Twenty SUDEP cases and 20 age- and sex-matched controls were included in the study. Femoral blood, cerebrospinal fluid, vitreous humor, and pericardial fluid were biochemically analyzed for sodium, potassium, calcium, glucose, N-acetyl- cysteine activated creatine kinase (CK-NAC) and isoenzyme CK-MB. Result: Serum sodium, CK-MB and CK-NAC level was found significantly increased and potassium level was found decreased in SUDEP cases in comparison to non-epileptic deaths. Likewise, in CSF, sodium and CK-NAC was found increased and potassium level was found decreased in SUDEP cases. In vitreous humor, sodium and CK-MB level was found increased and potassium level was found decreased in SUDEP cases in comparison to nonepileptic deaths. In pericardial fluid, sodium, CK-NAC and CK-MB level was found increased and potassium level was found decreased in SUDEP cases in comparison to non-epileptic deaths. Conclusion: It concludes that high sodium level and low potassium level could be associated with SUDEP. However, this is a small size study, a larger study is needed to verify the findings. Furthermore, it is difficult to conclude whether these findings are exclusive to SUDEP.