Clinical Significance of Hyperlactatemia and Acidosis in Patients with Suspected Generalized Convulsion

ABSTRACT

PURPOSE: To determine the clinical usefulness of lactic acidosis in an evaluation of patients with suspected generalized convulsion. METHODS: This was retrospective cohort study. The correlation between the lactate level and the time to blood gas analysis (ABGA) was analyzed in patients who had a final diagnosis of seizure to exclude the time effect on the spontaneous clearance of lactate. The patient's data in the true seizure group and false seizure group was then compared. The receiver operating characteristics (ROC) curve of lactate, pH and base deficit for diagnosing true seizure was drawn. The sensitivity and specificity of the presence of hyperlactatemia or acidosis for a diagnosis of seizure and predicting epileptiform discharge at electroencephalography (EEG) was analyzed. RESULTS: Of the 173 patients suspected of having generalized convulsion, 136 patients were diagnosed with a true seizure on hospital discharge and patients whose ABGA was performed within 60 minutes after seizure showed a significantly higher arterial lactate level, lower arterial pH and base deficit than the patients whose ABGA was performed after 60 minutes of seizure onset. 62 patients whose ABGA was performed 60 minutes after symptom onset were excluded. Finally, of 111 patients, 89 patients with true seizure showed a significantly higher arterial lactate level, lower arterial pH and base deficit than the 22 patients with false seizure. The ROC curve of lactate, pH and base deficit showed a significant area under the curve for diagnosing true seizure. The presence of hyperlactatemia or acidosis showed high sensitivity for diagnosing true seizure and expecting epileptiform EEG when they were measured with 60 minutes after symptom onset. CONCLUSION: In patients with suspected generalized convulsion, upon presentation to the ED within 60 min of symptom onset, the presence of hyperlactatemia or acidosis increased the likelihood of a true seizure and might be an objective indicator for further evaluations of seizure. On the other hand, normal lactate levels and no acidosis could not exclude a true seizure.