The presence of an NMO-specific antibody (Anti-aquaporin 4) in the CSF and serum has allowed these patients to be distinguished from those with multiple sclerosis. Neuromyelitis optica spectrum disorders are demyelinating disorders associated with attacks on the optic nerves and spinal cord. In comparison with the previous study, the follow-up scan showed a significant reduction in the cervico-dorsal intramedullary T2 hyperintensities (Fig 8,9) and relative reduction in the size of the left midbrain T2 hyperintensity (Fig 10), reflecting a good response to treatment. Repeat MRI brain and spine was done after 2 weeks. The patient was treated with intravenous immunoglobulin & Azathioprine following which his symptoms gradually improved. NMO Antibody (Serum and CSF) and oligoclonal bands were negative. CSF Anti-MOG (Myelin oligodendrocyte glycoprotein) antibody was positive. CSF analysis showed a total count of 60 cells with lymphocyte predominance, glucose - 86 mg/dl, and protein - 51.1mg/dl. Nerve conduction study was done which showed a mild delay in latencies. Based on the above finding, the possibility of neuromyelitis optica spectrum disorder (NMOSD) was suggested and the patient was subjected to laboratory workup for the same. Both optic nerves appeared relatively thickened with T2/ STIR hyperintensities in the left optic nerve (Fig 3,7). Discrete T2 hyperintensities were also noted in the left anterior midbrain (Fig 6). The nerve roots of the cauda equina appeared normal. Post-contrast administration, the cervico-dorsal lesion showed patchy enhancement (Fig 5).

The hyperintensities were seen predominantly involving the central and posterior parts of the spinal cord with relative sparing of the anterior portion (Fig 4). Subtle intramedullary T2 hyperintensities were also noted in the lower dorsal cord and conus medullaris (Fig 2). 3 Tesla MRI of Brain & spine was done which showed long segment intramedullary T2 hyperintensities in the spinal cord extending from the cervico-medullary region to D1 level (Fig 1,2), with expansion of the cervical cord.

Mog antibody optic neuritis