Cerebral vasculitis and lateral rectus palsy – two rare central nervous system complications of dengue fever: two case reports and review of the literature

BACKGROUND: Dengue fever is a common mosquito-borne viral illness with a clinical spectrum ranging from a simple febrile illness to potentially life-threatening complications such as dengue hemorrhagic fever and dengue shock syndrome. Dengue infection can affect many organs, including the central nervous system. The neurological manifestations reported in dengue infections are meningitis, encephalitis, stroke, acute disseminated encephalomyelitis, and Guillain-Barré syndrome. CASE PRESENTATION: We report the cases of two interesting patients with confirmed dengue infection who presented with complications of possible central nervous system vasculitis and cranial nerve palsy. The first patient was a 53-year-old previously healthy Singhalese woman who developed acute-onset slurring of speech and ataxia with altered sensorium 1 day after recovery from a critical period of dengue hemorrhagic fever. Subsequent investigations revealed evidence of encephalopathy with brainstem ischemic infarctions. Her clinical picture was compatible with central nervous system vasculitis. She was treated successfully with intravenous steroids and had a full functional recovery. The second patient was a middle-aged Singhalese woman who had otherwise uncomplicated dengue infection. She developed binocular diplopia on day 4 of fever. An ocular examination revealed a convergent squint in the left eye with lateral rectus palsy but no other neurological manifestation. CONCLUSIONS: Central nervous system vasculitis due to dengue infection is a very rare phenomenon, and to the best of our knowledge, only one case of central nervous system vasculitis has been reported to date, in a patient of pediatric age. Cranial nerve palsy related to dengue infection is also rare, and only a few cases of isolated abducens nerve palsy have been reported to date. The two cases described in this report illustrate the rare but important central nervous system manifestations of dengue fever and support the fact that the central nervous system is one of the important systems that can be affected in patients with dengue infection.