Dengue encephalopathy in children in Northern India: clinical features and comparison with non dengue.

Background: Acute febrile encephalopathy (AFE) is a common cause of childhood hospital admissions in Lucknow. In recent years, many patients have been hospitalized with AFE and hemorrhagic manifestations, some of whom were proven to have dengue viral infection.

Objectives: To (i) define the role of dengue encephalopathy (DE) as a cause of AFE in children in Lucknow, (ii) document features of dengue hemorrhagic fever (DHF) in them and (iii)compare clinical features of definite dengue and non dengue AFE.

Study Design: Prospective study at a teaching hospital in northern India. Children between 1-12 years of age hospitalized with fever and altered consciousness of 2 weeks or less duration were enrolled after excluding bacterial and tuberculous meningitis and frank hepatic encephalopathy. Clinical and laboratory details were charted. Haemagglutination inhibition (HI) test for dengue and Japanese encephalitis viruses in paired sera and IgM antibody capture ELISA for dengue were done. Real time PCR was done in those samples testing positive for dengue IgM. Those with either positive HI test or positive dengue PCR in CSF or serum were considered definite dengue infection and features of DHF were charted in them. Those negative for IgM antibodies after 5 days of illness or whenever done, HI test, were considered definite non dengue. Clinical and laboratory features were compared between definite dengue and non dengue groups.

Results: A total of 265 patients of AFE were enrolled over a 2 year period. HI test was positive in 15/49 (30.6%) and IgM in 52/238 (21.8%) patients thus tested. A total of 62 patients were positive for dengue antibodies by either test. Real time PCR assay for dengue virus genome was positive in 28/42 (69%) tested -- 21/29 (72.4%) in CSF and 9/15 (60%) in serum. A total of 39 patients met the criteria for definite dengue infection of which only 2 fulfilled the WHO criteria for DHF. Comparing DE and non DE, rash, bleeding, swelling over body, and hepatomegaly were significantly more common and meningeal signs less frequent in DE. Mean platelet counts and serum albumen were lower and liver enzymes and INR were significantly higher in DE.

Conclusions: Dengue viral infection is a cause of AFE in children in this region. Majority of DE here appears to be due to viral invasion of brain as suggested by high PCR positivity in CSF and lack of WHO criteria for DHF. Differentiating features of DE include swelling and hepatic dysfunction.