Risk Factors Associated With Hyperammonemia Following Unprovoked Convulsive Seizures.

Nurose Karim,Nicholas D Henkel,Giana Dawod,Ajaz A Sheikh

doi:10.7759/cureus.8504

Abstract

This report describes a unique case of recurrent transient hyperammonemia (THA) following a first-time occurrence of generalized tonic-clonic seizure in a young adult, who went on to develop post-stroke epilepsy. Although this phenomenon has been described in recent literature, we report not only the highest initial ammonia level to date, 549 µmol/L, but we also document serial trends of the ammonia levels at multiple admissions for the same patient for the management of breakthrough seizures. Interestingly enough, persistence of the elevation of the ammonia levels was accompanied by no other significant metabolic derangements, unlike reported in similar cases. Of prior studies, high ammonia levels have been reported in the context of alcohol-induced seizures, with resolution of ammonia levels within eight hours. Here, we highlight the importance of medication compliance, as well as the need for serial ammonia levels for improving patient outcomes, with the knowledge that ammonia accumulation leads to potential irreversible neurotoxicity. Additionally, we completed a systematic literature review on data pertaining to the risk factors associated with hyperammonemia following unprovoked convulsive seizures in an effort to analyze our case in the context of the existing literature. Our objective is to ultimately understand the utility of serial ammonia levels for unprovoked convulsive seizures in the context of the patient's initial presentation, and whether treatment of these episodes of hyperammonemia can significantly alter outcomes.

Highlights

The diagnosis of a seizure relies heavily on the clinical history, the initial workup for patients presenting to the emergency department (ED) includes both imaging and serum markers
This phenomenon has been described in recent literature, we report the highest initial ammonia level to date, 549 μmol/L, but we document serial trends of the ammonia levels at multiple admissions for the same patient for the management of breakthrough seizures
We completed a systematic literature review on data pertaining to the risk factors associated with hyperammonemia following unprovoked convulsive seizures in an effort to analyze our case in the context of the existing literature

Summary

Introduction

The electroencephalograms (EEGs) have shown left fronto-temporal interictal epileptiform discharges, video-EEG recording showed electrographic seizures arising from right temporal region, indicating bihemispheric epileptogenicity After his first seizure, his ammonia level was initially 549 μmol/L, with slightly elevated liver enzymes, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) being below 100 units/L, and normal renal function. His ammonia level was initially 549 μmol/L, with slightly elevated liver enzymes, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) being below 100 units/L, and normal renal function At that time, he was started on phenytoin 200 daily and valproic acid 250 twice a day. Valproate has been associated with hyperammonemia in the postictal state; this does not explain our findings since he was on it for less than a month His ammonia levels remained elevated past eight hours, which is the longest reported period of postictal ammonia levels.

Discussion

Conclusions

Findings

Disclosures