This is an etiological study of 407 cases of Acute Encephalitis Syndrome (AES) admitted during August – October 2016 in BRD Medical College (BRDMC) – a tertiary care hospital in Gorakhpur, Uttar Pradesh.
Inclusion: AES + CSF pleocytosis (>5cells/ccm) were included. Out of 1037 patients who had AES with CSF pleocytosis, 407 cases were selected randomly and their blood and CSF samples were subjected for etiological analysis. Sera were tested for presence of Scrub typhus IgM antibodies (ST), Japanese Encephalitis Virus (JEV) and dengue. CSF was tested for presence of IgM antibodies against JE and OT. Genomic DNA from whole blood and CSF are extracted and PCR for ST and SFGR (Spotted Fever Group of Rickettsia) were done.
Of the 407 AES patients, 266 (65.4%), 42 (10.3%) and 29 (7.5%) were diagnosed to have ST, JEV and dengue respectively. Four patients were diagnosed to have SFGR infection. A significantly higher proportion of scrub typhus patients with AES had hepatomegaly, splenomegaly, and facial edema. The common hematological and biochemical abnormalities among ST positive patients include thrombocytopenia raised liver enzymes and bilirubin levels.
The case fatality ratio was significantly higher among ST negative AES patients (36.2% vs 15.2%, p<0.05). Azithromycin was given to 96% of patients.
About two thirds of patients presented more like an AFI later complicated with AES – they had longer history of illness, rash, thrombocytopenia and elevated liver enzymes; their scrub tyhus serology was positive and PCR was positive in a minority of people. They also had a better prognosis. Brain biopsy and serology also showed evidence of Rickettsial spotted fevers being present as well.
A significant minority of patients had more than one etiological diagnosis and no patient had an eschar, which suggests overdiagnosis of scrub typhus. Still, empiric therapy for scrub typhus in patients with encephalitis appears reasonable till the diagnosis is excluded.