A rare case of dengue encephalitis.

Dengue fever has a variable clinical spectrum ranging from asymptomatic infection to life-threatening dengue haemorrhagic fever and dengue shock syndrome. However, neurological complications, in general, are unusual. Dengue encephalopathy is not an unknown entity; however, dengue encephalitis, a direct neuronal infiltration by the dengue virus, is an extremely rare disease. Although dengue is classically considered a non-neurotropic virus, there is increasing evidence for dengue viral neurotropism, suggesting that, in a proportion of cases, there may be an element of direct viral encephalitis. An MRI brain rarely shows focal abnormalities in dengue encephalitis. We report an interesting case of dengue encephalitis during an outbreak in Delhi, India. The diagnosis was confirmed by blood and cerebrospinal fluid dengue serology and (NS1) antigen assay. The case showed extensive lesions involving the midbrain, cerebellum, thalamus and medial temporal region on both sides of the MRI brain, which is an uncommon manifestation of dengue fever.