Opsoclonus Myoclonus syndrome (OMS) is described as a classical paraneoplastic syndrome having an incidence of 1 in 10 million per year, and can often be associated with anti-Ri antibodies. We describe a patient with OMS, who had a previous (and completely treated) diagnosis of Breast cancer more than 10 years ago, who presented with features of dizziness, opsoclonus, generalised myoclonus and truncal ataxia. Investigations revealed positive anti-Ri antibodies, but comprehensive screen for an underlying malignancy was negative.
Patient was initially treated with intravenous immunoglobulins (IVIg) with good response. However, despite this patient had a further relapse which required hospitalisation with ventilator support and another course of IVIg. A second relapse was treated with pulsed IV cyclophosphamide and after a prolonged hospital stay she was discharged home. Unfortunately she relapsed again few months later, at which stage she was given Rituximab after obtaining approval through the NHS England Individual Funding Request pathway. She slowly improved and was able to go home despite an initial prolonged intensive care stay. Unfortunately several months later she had a further relapse which was unresponsive to any immunomodulatory treatments.
OMS is a rare autoimmune neurological disease, which can respond partially to Rituximab.