Correlation between serum lactate dehydrogenase (LDH) and seizure : an observation in clinical cases

Introduction: Serum lactate dehydrogenase (LDH) is an enzyme that catalyses the interconversion of lactate and pyruvate. LDH inhibition can reduce the excitability of neurons in mice; this leads to a hope that LDH inhibitor may be used to treat seizure. Translating this laboratory experimental finding to clinical medicine, one would like to investigate the potential correlation between serum LDH and seizure in humans. Objective: The objective of this study is to investigate the question: "Would a patient with an acute illness, who has seizure as one of the clinical manifestations, have an elevated serum LDH before, during, or after an episode of seizure?" Method: The PubMed database was searched on 30th August 2015. The search algorithm was: (epileps* OR seizur*) AND (lactate dehydrogenase* OR LDH). Patients with known established conditions that could elevate LDH were excluded. Results: Fifteen clinical cases met the inclusion criteria and were reviewed. Their serum LDH levels in relation to a seizure event were studied. The ratios of serum LDH levels to the upper limit of the reference ranges were all above 1.0 (ranging from 1.4 to 23.1). Conclusion: Patients with an acute illness, who had seizure as one of their clinical manifestations, had elevated serum LDH above the upper limit, before, during, or after an episode of seizure.