Changing Clinical Profile and Predictors of Mortality in Patients of Acute Febrile Encephalopathy from North India
Authors: Ary Kunwer Abhishek , Singh Harpreet , Suri Vikas , Sharma Kusum , Biswal Manisha , Singh Mini P. , Ahuja Chirag Kamal , Kharbanda Parampreet , Sharma Navneet , Bhalla Ashish 
Published: August 2023

Introduction:
Acute encephalitis syndrome (AES) or acute febrile encephalopathy is a clinical condition characterized by altered mental status occurring after or along with a short febrile illness. In developing countries, infections are the predominant cause of AES. Prominent infections known to cause AES include viruses (such as herpes simplex virus [HSV], Japanese Encephalitis [JE] virus, dengue, enteroviruses [EVs]), bacteria, fungus, and parasites. In the present study, we aim to analyze the etiology, clinical features, and predictors of mortality in patients presenting with acute febrile encephalopathy or acute encephalitic syndrome. The present study was a prospective observational study conducted at Post Graduate Institute of Medical Education and Research a tertiary care center in Chandigarh, India.

Methods:
A total of 105 patients with ≥18 years of age with fever (body temperature >101° F for duration ≤14 days) and altered sensorium (Glasgow coma scale [GCS] score ≤10) lasting for more than 24 h, either accompanying the fever or following it were enrolled. Demographic and clinical details were recorded on pro forma. Cerebrospinal fluid (CSF) analysis was performed for all the enrolled patients at admission for cytology, CSF glucose to blood glucose ratio, protein levels, gram stain and culture sensitivity, adenosine deaminase levels, polymerase chain reaction for HSV/EV/mycobacterium tuberculosis (TB) and immunoglobulin M Enzyme-linked immune assay for JE. Computed tomography of the brain was done in all patients while magnetic resonance imaging (MRI) of the brain was carried out in 75 patients.

Results:
Among the 105 patients, tubercular meningitis was seen in 27 (25.7%) patients followed by acute pyogenic meningitis in 18 (17.1%) patients. Probable viral encephalitis was present in 12 (11.4%) cases. Septic encephalopathy (n = 10) and scrub typhus encephalitis (n = 8), HSV encephalitis (n = 6), dengue encephalitis (n = 4), leptospirosis (n = 3) were the other infections causing acute febrile encephalitis in our study. In addition to fever and altered sensorium common symptoms observed were headache (52.4%), vomiting (35.2%), and seizures (29.5%). The factors predicting increased mortality were female gender, fever of more than 38°C at admission, GCS <7, MRI showing disease-related findings like altered signal intensity bilateral medial temporal and insular area in herpes simplex encephalitis, etc., changes, and the group of patients where a definite diagnosis could not be established during the hospital stay.

Conclusions:
Tubercular meningitis/central nervous system TB is the predominant cause of acute febrile encephalopathy in developing countries. Scrub and dengue encephalitis are emerging as an important cause of acute febrile encephalopathy and occur predominantly in postmonsoon seasons. Acute febrile encephalopathy remains an important cause of mortality in patients presenting to Emergency Department (ER). The strongest predictors of mortality are low GCS and undiagnosed cases of AES.