Bilateral Abducens Nerve Paresis: A Rare Manifestation of Dengue Fever

Dengue fever is endemic in over 100 countries, with the majority of cases reported in the World Health Organization (WHO) regions of the Americas, Southeast Asia and the Western Pacific. Dengue fever is endemic in almost every state in India, and it is the leading cause of hospitalisation. The presentation may vary from being asymptomatic to having mild syndrome. Among other neuro-ophthalmological manifestations, oculomotor neuropathy, optic neuropathy and unilateral abducens nerve palsy has been reported but to the best of authors' knowledge this is the first reported case of dengue virus related type three internuclear Ophthalmoplegia. A 47-year-old male patient presented with complaints of fever on and off for the last 3 days along with speech defects. At admission his blood pressure was 120/86 mmHg, pulse rate was 96 per minute. Oxygen saturation (SpO(2)) was 94%. He was thoroughly investigated for various viral and bacterial infections, none of which was detected in Polymerase Chain Reaction (PCR) serum test. Hepatitis B virus surface antigen (HBsAg), antibody against Hepatitis C Virus (anti-HCV), antibody against Human Immunodeficiency Virus type 1/2 (anti-HIV 1/2) were all negative. Anti-dengue virus Immunoglobulin M (IgM) antibody was found to be positive. The patient complained of double vision and on examination diplopia in both lateral gaze with maximum separation of images in right gaze. Due to the wider range of possible presentations, it is imperative to consistently follow-up with all dengue patients to check for any neurological sequalae.