A young woman with seizures, visual impairment, and paralysis.

Background: Anti-MOG encephalomyelitis is a recently described demyelinating, autoimmune disease of the central nervous system, identified by antibodies against myelin oligodendrocyte glycoprotein (MOG).
Case Presentation: A previously healthy 20-year-old woman was admitted to hospital after a seizure. MRI showed leptomeningeal enhancement and lumbar puncture revealed moderate pleocytosis but no evidence of infection. Over the following months, she experienced a series of neurological deficits including bladder dysfunction, loss of sensation in the lower extremities and genital area, impaired motor function of the legs and episodes of visual loss. All symptoms had MRI correlates in the medulla, brainstem, optic tract, thalami and corpus callosum. She responded excellently to corticosteroid treatment, but experienced relapses shortly after discontinuation of treatment. Repeated lumbar puncture revealed pleocytosis up to 475 ∙ 106 cells/l but there were no signs of intrathecal IgG synthesis or infection. Serum anti-MOG antibodies were detected two months after the initial episode. She has been treated with low dose corticosteroids in combination with rituximab for two years, without clinical or radiological relapse.
Interpretation: Symptoms and signs mimicking acute demyelinating encephalomyelitis and neuromyelitis optica are typical for anti-MOG encephalomyelitis. This case illustrates that the response to corticosteroids may be excellent but transient, and that the disease can be controlled with moderate immunosuppression.