Opsoclonus myoclonus Ataxia syndrome (OMAS) is a rare disorder characterised by abnormal eye movement, myoclonus and ataxia. In paediatric population, paraneoplastic OMAS is the most common cause while in adults it is idiopathic and para infectious.

A 39-years-old-male without any prior comorbidities presented with history of fever (NS1 antigen positive) 20-days back. Fever had subsided by fifth day of illness. On seventh day, he noted acute onset tremulousness while approaching for any object with either of his hands, which was followed by swaying of body to either side while walking. On the tenth day of illness, he had difficulty in standing or sitting independently and he remain confined to bed. He prefer to keep his eyes shut due to severe chaotic eye movement. He was communicating with hand gestures due to severe voice tremors. He later started to experience abnormal intermittent involuntary jerks of all the four limbs, without any loss of consciousness.

He was admitted in neurology ward with above complaints on day fifteen of his illness. On examination he was having GCS, E4V5M6. Ocular examination showed abnormal chaotic, rapid, multidirectional eye movements which did not subside even with fixation of eyes. Cerebellar examination revealed limb ataxia, dysarthria, titubation and truncal ataxia with intermittent myoclonic jerks. Rest of the other neurological examinations were well within normal limits.

Routine blood investigations were normal except dengue IgM test positivity. CRP 149mg/dl and ESR 55 mm/hour, were raised. MRI-brain and CSF examination were normal. Other investigations were unremarkable.

He was treated with intravenous methyl prednisolone (1gm) for 5 days followed by oral steroid. After 12 days of treatment he had improved significantly.

Adult onset acute severe OMAS is a rare condition.  Dengue fever with OMAS is extremely rare combination and should always kept in mind in the endemic countries.