Predictive Value of Plasma Electrolyte Levels in the Diagnosis of Seizures

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.Material and 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, convulsion, stroke, or cerebrovascular disease. Patients were divided into seizure (n=418) and non-seizure (n=1398) groups. Demographic characteristics, electrolyte levels, lactate, creatine kinase, and uric acid values were compared. Risk analyses for electrolyte disturbances, logistic regression with seizure as the outcome, and ROC curve analyses were performed.Results: Seizure patients were younger than non-seizure patients (56 35–71 vs. 68 53–78, p0.001). Lactate (3.30 1.90–6.50 vs. 2.00 1.50–2.70, p0.001) and creatine kinase levels were significantly higher in the seizure group. Hypocalcemia, hypercalcemia, hypophosphatemia, hyperphosphatemia, and hyperuricemia were associated with seizures, whereas hyperchloremia appeared protective. In multivariate logistic regression, only lactate was identified as an independent predictor of seizure (OR: 1.383, 95% CI: 1.280–1.494; p0.001). Lactate had the highest discriminatory power in ROC analysis (AUC=0.705), while the overall multivariate 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 analyses, none remained independent predictors. These findings suggest that lactate measurement may provide valuable diagnostic support in distinguishing seizures from other causes of transient loss of consciousness.