Opsoclonus Myoclonus Syndrome

Abstract

Opsoclonus-myoclonus syndrome (OMS) refers to the combination of irregular, multidirectional, and chaotic eye movements that occur in all planes of gaze and is exacerbated with smooth pursuit. In addition, myoclonus, ataxia, or behavioral changes occur. Although often associated with neuroblastoma, OMS was first described in cases of encephalitis, but can occur due to various etiologies such as infections, a paraneoplastic phenomenon, or an idiopathic syndrome. OMS is rare. The pathophysiology of OMS remains unknown; however, several hypotheses have been proposed and will be discussed in this chapter. Patients usually present subacutely and require prompt workup which includes blood and cerebrospinal fluid for infections and paraneoplastic antibodies as well as imaging for occult malignancies. Treatment options include various immunomodulatory medications; however, chronic sequelae are common.