DX39
Opsoclonus-Myoclonus in a 14-Year Old Multiple Sclerosis Patient Receiving Natalizumab
Opsoclonus-Myoclonus Syndrome (OMS) is a rare neurologic disorder most commonly diagnosed in very young pediatric patients. Paraneoplastic (especially neuroblastoma and neoplasms of reproductive organs), viral infections, and idiopathic etiologies are most common. The clinical features of OMS include rapid, conjugate, and random saccadic eye movements. Myoclonus is most often reported in the head, neck and limbs. Treatment is focused on symptom responsiveness. Therapy with acetylcholine, steroids, and/or immunoglobulin (Ig) has proven most beneficial.
Objectives:
To describe the disease course and treatment of OMS in a multiple sclerosis (MS) patient receiving natalizumab.
Methods:
14-year old MS patient with severe clinical and radiologic disease had fewer relapses and stable radiographic findings during treatment with nataluzimab. She is John Cunningham virus (JSV) antibody (Ab) negative. After her 23rd dose, patient developed visual disturbances, ataxia, and vertigo. These symptoms began after recovery from two weeks of intermittent vomiting and diarrhea. Upon examination, her eye movements were saccadic in all directions, but conjugate; gait was wide-based and ataxic with infrequent limb myoclonus. Romberg was positive.
Results:
Magnetic resonance imaging (MRI) showed slight increase in small plaques, but no enhancing lesions or other abnormalities inconsistent with MS. Remarkable findings on lumbar puncture (LP) were elevated Herpes virus Ab and elevated Coxsackie B Abs on four of six strains. Cerebrospinal fluid JCV Ab, serum paraneoplastic panel and N-Methyl-D-Aspartate (NMDA) receptor Ab, and urine for metanephrines were negative. Transvaginal ultrasound of the reproductive organs to exclude a neoplasm was normal. Three doses of methylprednisolone (1 gram each) were infused intravenously (IV). Initial improvement was noted, but recurrence of opsoclonus, vertigo and ataxia occurred within two days. Three more doses of methylprednisolone were administered with little effect. Further treatment with five doses of 25 grams of IVIg over five days resulted in notable symptomatic improvement within one week that continued to improve with eventual complete resolution of symptoms.
Conclusions:
A viral etiology for OMS in this case is most likely, and treatment with a combination of methylprednisolone and IVIg proved to be successful. A causal relationship between natalizumab and OMS cannot be drawn. Watchful management of further complications or recurrences is necessary.