A study on epidemiological pattern of acute encephalitis syndrome with special reference to japanese encephalitis in Patna medical college and hospital, Patna, Bihar, India
Authors: Tiwari Anil Kumar , Jaiswal Anil Kumar , Iqbali Tauhid 
Published: May 2017

Background: Acute Encephalitis Syndrome (AES) is defined as a person of any age, at any time of year with the acute onset of fever and a change in mental status (including symptoms such as confusion, disorientation, coma, or inability to talk) and/or new onset of seizures (excluding simple febrile seizures). Viruses have been mainly attributed to be the cause of AES in India although other etiologies such as bacteria, fungus, parasites, spirochetes, leptospira, toxoplasma, rickettsia, chemical, and toxins have also been reported over the past few years. The causative agent of AES varies with season and geographical location, owing to wide range of causative agents and the rapid neurological impairment due to pathogenesis, clinicians face the challenge of a small window period between diagnosis and treatment. The present study is dedicated to knowing the present epidemiological pattern of AES in Bihar aiming to help in diagnosis and treatment.Methods: This is a prospective study conducted in the department of pediatrics, Patna Medical College and Hospital, Patna from January 1st to December 31st, 2016, in this study all cases which presented with acute onset of fever and a change in mental status including symptoms such as confusion, disorientation, coma or inability to talk and/ or new onset of seizures excluding simple febrile seizures were included. Demographic, etiological analysis and outcome of cases of Acute Encephalitic Syndrome as well as Japanese encephalitis were done.Results: The total number of patient diagnosed clinically with AES were 186 of them 105 were male and 81 were female. Number of cases were highest in the age group of >5-10 years amounting to 37.7% followed by 26.4% in >2-5 years age group, marked male predominance was seen in the age group 5 -10 years. A minor female predominance was observed in the age group >10 years. In May number of cases were maximum 36 (19.4%) followed by April 32 (17.2%), number of cases of AES were least in the month of December followed by November (8). Maximum number of cases were from the district of Patna and its neighboring district amounting to 58.5% with Nalanda district alone comprises 24.3%. Etiological analysis reveals that 36.5% children admitted with the clinical diagnosis of AES, 36.5% were diagnosed with Acute bacterial meningoencephalitis and 22.04% were diagnosed with Japanese Encephalitis, 7.5% Tuberculous meningitis, 6.4% Cerebral malaria, 5.4% Herpes simplex encephalitis and 3.2% with acute encephalitis syndrome unknown.Conclusions: Acute Encephalitis Syndrome remains an important cause of prolonged hospital bed occupancy with a high rate of mortality. Although in JE positive cases mortality were less, but morbidity in form of various motor deficit and cognitive impairment increases the burden on the family and society. With the introduction of effective JE vaccine and with rigorous surveillance of AES cases and social initiative taken by the Government, we can hope a better scenario. More and more extensive studies are the need of hour to know more about the etiopathogenesis of AES, so that future strategies to bring down the mortality and morbidity due to this disease can be carried out.