Prognostic factors of subacute comprehensive encephalitis: a retrospective study.

Purpose: The etiology of encephalitis is unknown in 40%-50% of cases, so a comprehensive examination of encephalitis would be significant and meaningful. The short-term outcomes in appropriately managed patients are also unknown. Short-term clinical outcomes following onset can provide clinicians with clues regarding the clinical course in the immediate future. We investigated cases of encephalitis, including viral and autoimmune encephalitis, to determine the predictable risk factors that can be assessed to determine a short-term prognosis. Methods: We studied 90 patients with encephalitis. Poor and good outcomes were defined as scores of ≥3 and ≤2 on the modified Rankin scale, respectively. Multivariate logistic regression analysis using 19 independent variables was performed. Results: Multivariate logistic regression analysis identified cranial magnetic resonance imaging (MRI) lesions (odds ratio [OR], 3.119; 95% confidence interval [CI], 1.166-8.344; p = 0.023) and the need for mechanical ventilation (OR, 4.461; 95% CI, 1.685-11.813; p = 0.003)) as being significantly associated with poor outcomes. In 57 patients with subacute encephalitis presenting with cranial MRI lesions, bilateral lesions on cranial MRI (OR, 5.078; 95% CI, 1.516-17.007; p = 0.008) and the need for mechanical ventilation (OR, 4.461; 95% CI, 1.135-13.584; p = 0.031) were significantly associated with poor outcomes. Conclusion: The location of brain lesions, lateral or bilateral, on the initial MRI during the acute phase of encephalitis may be a useful predictor of the outcome during the first 2 months after encephalitis onset, even in cases of encephalitis of unknown etiology.