Thrombocytopenia as a Prognostic Marker in Patients with Acute Encephalitis at a Tertiary Care Center in Northern India.

Background: Acute encephalitis (AE) is associated with a high burden of mortality and permanent disability and has a spectrum of underlying etiologies. The prognosis of encephalitis is difficult and almost all the patients seem to be at a high risk of poor outcomes. A number of physiological changes take place during encephalitis and have been evaluated for their prognostic value. Platelet count, which has been recognized as a surrogate prognostic marker in various viral illnesses, has recently been recognized to have a prognostic value in AE too. In the present study, we attempted to study the role of thrombocytopenia in the prognosis of AE.

Methods: Total of 98 cases based on clinical, cerebrospinal fluid, and radiological profiles consistent with the diagnosis of AE were enrolled in the study. A clinical profile was noted, and platelet count was assessed. Thrombocytopenia was defined as platelet count <150,000/mm3. Platelet count 100,000-150,000, 50,000-99,999, and <50,000/mm3 were considered mild, moderate, and severe thrombocytopenia. The underlying etiology was explored, and patients were followed till discharge/outcome. The outcome was noted in terms of the Modified Rankin score (MRS). MRS 0-2 was considered good, 3-4 fair, and 5-6 as poor outcome.

Results: The mean age of patients was 34.06 ± 18.76 years. Majority of patients were women (54.1%). Prevalence of thrombocytopenia was 75.5%. A total of 34 (45.9%) had mild, 30 (40.5%) had moderate, and 10 (13.5%) had severe thrombocytopenia. Acute viral encephalitis (unclassified) was the most common etiology (33.7%), followed by scrub meningoencephalitis (24.5%) and Japanese encephalitis (12.2%), respectively. Good, fair, and poor outcomes were noted in 48 (49%), 21 (21.4%), and 29 (29.6%) cases. On univariate analysis, no significant association of poor outcome was seen with age, sex, duration of fever, and mechanical ventilation need (P > 0.05). Low Glasgow Coma Scale (GCS), splenomegaly, low platelet count, and Japanese encephalitis virus/scrub typhus etiologies were found to be significantly associated with poor outcomes (P < 0.05). Thrombocytopenia compared to normal platelet count and severe thrombocytopenia compared to mild and moderate thrombocytopenia were significantly associated with poor outcomes (P < 0.05). On multivariate analysis, GCS <8 (odds ratio [OR] =4.52; 95% confidence interval [CI] =1.56-13.20) and thrombocytopenia (OR = 11.92; 95% CI = 1.38-103.32) emerged as independent predictors of poor outcome.

Conclusions: The findings of the study showed that low GCS and thrombocytopenia could be used as predictors of poor outcomes in AE cases.