PO140 An unusual presentation of nmo, and mri review of 31 nmo patients

A 31 year old lady was admitted with worsening of right sided hemiparesis, on a background five month history of mild right upper limb weakness, and upper limb sensory ataxia. MRI revealed a longitudinally enhancing intrinsic cord lesion from C2-C7 with severe cord expansion, raising initial suspicion for ependymoma. Inflammatory aetiology was considered due to multiple areas of involvement, with T2-weighted signal change within the cervical and thoracic spine, and brain. CSF revealed 4 mononuclear cells, normal protein, normal CSF-serum glucose ratio, T lymphocyte predominance on histology, and no neoplastic cells on flow cytometry. Testing for tuberculosis was negative, including CSF, and extensive imaging did not reveal malignancy. Aquaporin-4 antibodies were positive, and the patient showed marked improvement to intravenous steroids and oral taper, with significant radiological resolution at two months. This case highlights an unusual presentation of NMO, with progressive history over five months, and unusual radiological findings, including severe cord expansion. Positive aquaporin-4 antibody and excellent clinical and radiological response to immunosuppressive therapy confirmed the diagnosis. We took this opportunity to review the clinical presentation and MRI findings in 31 of our five year NMO patient cohort (26 aquaporin-4 antibody positive, 3 anti-MOG positive and 2 seronegative).