Scrub Typhus-Associated Opsoclonus: Clinical Course and Longitudinal Outcomes in an Indian Cohort

Context: Opsoclonus, a rare neurological manifestation in scrub typhus, causes significant distress and disability. There is a paucity of clinical data and outcomes in these patients. Aim: This study aims to describe the clinical and laboratory profile and longitudinal outcomes in a scrub typhus patient cohort with opsoclonus. Settings and Design: This retrospective study was conducted in a 2700-bed teaching hospital in South India, in scrub typhus patients with opsoclonus over a 5-year period. Patients and Methods: Clinical, laboratory, and radiological data and outcomes at discharge and 6-and 12-weeks postdischarge were documented. Results: Of 1650 scrub typhus patients, 18 had opsoclonus. 17 had opsoclonus at presentation, while one patient developed opsoclonus on the 5th admission day, 1-day postdefervescence. Opsoclonus was first noted after a median interval of 11 (7-18) days from fever onset. It was associated with myoclonus in 94% (17/18), cerebellar dysfunction in 67% (12/18), extrapyramidal syndrome (EPS) in 33% (6/18), and aseptic meningitis in 17% (3/18) patients. Mean cerebrospinal fluid (CSF) white blood cell (WBC) count was 9 +/- 2.7 cells/cumm, with mean CSF protein 118.5 +/- 53.9 mg% and mean CSF glucose 97 +/- 13 mg% in 1l/15 patients. Brain magnetic resonance imaging was unremarkable in 75% (9/12). Case-fatality rate was 5.5% (1/18). Complete resolution of the index neurological syndrome occurred at 12-week postdischarge. Conclusions: Opsoclonus is a rare neurological manifestation in scrub typhus, usually occurring in association with myoclonus, cerebellar dysfunction, or EPS. It appears to occur during the resolving febrile phase, with neurological deficits completely resolving at 12 weeks.