Predictive value of plasma electrolyte levels in the diagnosis of seizures

ABSTRACT Aim: To evaluate the predictive value of plasma electrolyte levels and biochemical parameters in diagnosing seizures among adult patients presenting to the emergency department (ED) with loss of consciousness. Methods: This retrospective, single-center study included 1816 adult patients admitted to the ED of a tertiary university hospital between January 1, 2021, and January 1, 2024, with diagnoses of syncope (R55), convulsion (R56), stroke (I61), or cerebrovascular disease (I67). Patients were divided into seizure (n=418) and non-seizure (n=1398) groups. Demographic features, electrolyte levels, lactate, creatine kinase, and uric acid values were compared. Risk analysis, logistic regression, and ROC curve analyses were performed. Results: Seizure patients were younger than non-seizure patients (56 [35–71] vs. 68 [53–78], p<0.001). Lactate (3.30 [1.90–6.50] vs. 2.00 [1.50–2.70], p<0.001) and creatine kinase levels were significantly higher in the seizure group. With respect to electrolyte disorders, hypocalcemia, hypercalcemia, hypophosphatemia, hyperphosphatemia, and hyperuricemia were found to be associated with seizures, whereas hyperchloremia was identified as inversely related to seizure occurrence (OR: 1.383, 95% CI: 1.280–1.494; p<0.001). Lactate had the highest discriminatory power in ROC analysis (AUC=0.705). The overall regression model achieved an AUC of 0.720. Conclusion: Elevated lactate levels serve as a strong biomarker for seizure diagnosis in ED patients presenting with loss of consciousness. Although several electrolyte disturbances were associated with seizures in univariate analysis, none remained independent predictors. These findings suggest that lactate measurement may provide valuable diagnostic support in clinical practice. Keywords: Seizure, Electrolyte Disturbances, Lactate, Emergency Department, Biomarker