P45. A case of NMDA-positive myelitis in a 41 year old male

Abstract

NMDA-IgG-positive limbic encephalitis is a clinical condition known since 2007. Since then many case series have been published, indicating a high prevalence especially in young women. Here, we present the case of a 41 year-old male presenting with multisegmental myelitis as the predominant condition caused by NMDA-IgG antibodies. He was first admitted to our hospital in May 2014 because of progressive gait disturbance for 4 weeks. Examination revealed spastic-atactic gait disturbance and hypaesthesia in both lower limbs and the lower trunk region. He had never had any seizure nor he or his family reported any mnestic disturbances or psychic alterations. Whole spine MRI showed a largely contrast enhancing longitudinal myelitis concerning all parts of the spinal cord mostly pronounced in the cervical regions. An MRI Scan of the brain showed only a very discrete lesion around the back of the left second ventricle, slightly contrast enhancing and thus indicating acuity of this lesion. CSF cell count, lactate and glucose levels were normal, but protein concentration was increased to 109 mg/dl. Oligoclonal bands were negative as well as aquaporin-antibodies. ANA, ANCA and ds DNA showed normal results. Further laboratory testing for autoimmune disorders revealed positive IgG for NMDA-antibodies first in the blood sample, which could be confirmed in the cerebrospinal fluid too (IgG+ 1:1), enabling us to diagnose an acute NMDA-Myelitis with only very slight morphologic but no clinical signs of encephalitis in our patient.Extensive investigations for paraneoplastic causes of the NMDA-encephalomyelitis remained normal. Therapeutically, the patient received high dose iv. prednisolone therapy starting with 1000 mg per day and escalating to 2000 mg per day without a clinical response. Thus, we performed seven sessions of plasmapheresis leading to improvement after the fourth treatment. The patient recovered slowly and his gait improved already during the stay at our hospital. He was then referred to rehabilitation. At clinical control four month after demission, the patient has recovered almost completely leaving only marginal signs of muscle tone elevation in the left leg and he has never developed any cerebral signs. NMDA-IgG is negative in the CSF now. He is still under immunosuppressive treatment with methotrexate 15 mg/week p.o. in order to avoid corticosteroids.