Opsoclonus-myoclonus syndrome and HIV-infection

Opsoclonus-myoclonus syndrome (OMS) typically presents with chaotic eye movements and myoclonus with some patients exhibiting ataxia and behavioural disturbance. The pathogenesis may be inflammatory with an infectious or paraneoplastic trigger. In this report, we describe four HIV-infected cases with OMS presenting to a tertiary referral centre in Cape Town, South Africa, over a 10-year period. OMS was the initial neurological presentation of HIV-infection in three subjects of whom two had preserved CD4+ cell counts. Immunosuppressive therapy, mainly prednisone, led to a dramatic improvement of symptoms in all cases suggesting an inflammatory aetiology, consistent with the observation that HIV-infection can be associated with both inflammatory and autoimmune conditions. Three previous reports of OMS associated with HIV-infection have been documented including a sero-conversion syndrome and as part of an immune reconstitution syndrome. We suggest that in HIV-associated OMS the pathophysiology may be the consequence of a dysregulated immune system in which a reduced CD4/CD8 ratio, in addition to a critical level of functional CD4+ cells for efficient CD8+ cytotoxicity, results in dysfunction of the brainstem-cerebellar circuitry in susceptible individuals.