Prevalence and factors associated with seizures among patients with infective encephalitis

Seizures are a common and clinically significant complication of infective encephalitis, often associated with greater disease severity and poorer neurological outcomes. Identifying reliable clinical and diagnostic predictors of seizures is critical to improve early risk stratification and guide targeted management. However, regional data on the seizure prevalence and associated factors in encephalitis remain limited. This study aims to determine the prevalence, clinical characteristics, and risk factors associated with seizure occurrence in patients with infective encephalitis admitted to a tertiary care centre in Malaysia.

We conducted a retrospective observational study involving 173 patients diagnosed with infective encephalitis and admitted to a tertiary referral hospital. Data on demographics, clinical presentation, Glasgow Coma Scale (GCS) scores, electroencephalography (EEG), neuroimaging, and cerebrospinal fluid (CSF) parameters were extracted from medical records. Seizure occurrence and characteristics were analysed. Statistical analyses included univariate and multivariate logistic regression to identify independent predictors of seizures. Missing data for selected variables were imputed using median substitution based on the distribution of available data.

Seizures were reported in 55.5% of patients (n=96), with generalised seizures being more common than focal. EEG abnormality emerged as the most significant independent risk factor for seizure occurrence (aOR 5.22, 95% CI 2.22-12.26, p <0.001). Altered behaviour (aOR 0.22, 95% CI 0.11-0.45, p < 0.001) and elevated CSF protein (OR 0.44, 95% CI 0.20-0.95, p = 0.036) were significantly associated with lower odds of seizures. Functional outcomes at discharge (assessed by Glasgow Outcome Scale), showed that higher seizure burden, particularly status epilepticus (p<0.001) and increased seizure frequency (p=0.008) was significantly associated with poorer recovery at discharge.

This study confirms the substantial clinical burden of seizures in infective encephalitis and highlights the need to prioritise systemic risk stratification in routine care. EEG abnormality is the strongest independent predictor of seizure risk and should be incorporated into early diagnostic evaluation for risk stratification. Early EEG monitoring, timely antiseizure management, and structured neurological assessment are critical to mitigate secondary brain injury and optimise outcomes.