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.