A Unique Case of Unilateral Oculomotor Nerve Palsy Secondary to Dengue Fever

A wide range of ocular complications may arise from the mosquito-borne illness, dengue fever. We report a case of isolated unilateral oculomotor nerve palsy due to complications of dengue fever. A 50-year-old male with serologically confirmed dengue fever presented with a sudden onset of double vision with left eyelid drooping and left eye outward deviation on his day 8 of illness. Ocular examination revealed binocular diplopia with complete left eye ptosis and restriction of all left eye movements except for abduction. His left eye pupil was 8 mm dilated with a negative relative afferent pupillary defect (RAPD). A clinical diagnosis of left eye oculomotor nerve palsy with pupil involvement was established. Urgent contrasted brain imaging tests were performed and revealed to be normal. He was managed conservatively and had complete resolution of symptoms with good vision recovery within 3.5 months. Cranial mononeuropathy may be one of the various complications following dengue fever, as demonstrated in this case report. As it is an uncommon presentation, there is a need to exclude other acute causes of cranial nerve palsy. Visual prognosis is still favorable with judicious monitoring and without any treatment of steroids or immunoglobulin.