Neuromyelitis Optica

The set of MRIs shown here are from a middle-aged woman with neuromyelitis optica (NMO) – an autoimmune astrocytopathy. She was diagnosed with left sided optic neuritis 18 months ago, at that time presenting with subacute onset of left eye visual loss, as well as pain upon eye movement. There were no other neurological symptoms of note. Detailed eye examination revealed a markedly impaired left eye visual acuity, impaired colour vision as well as a left relative afferent pupillary defect. MRI of the orbits (Figure 1) revealed hyperintensity of the left retrobulbar optic nerve  on T2W sequence, and was contrast enhancing on T1W scan. Blood tests for anti-aquaporin-4 antibody (NMO-IgG) was positive. She was diagnosed with an NMO spectrum disorder initially and was treated with a 2 week course of high dose intravenous then oral steroids which was gradually tailed off and replaced by a steroid-sparing agent – azathioprine, with monitoring of her complete blood counts and liver function tests.

Her vision recovered partially during the subsequent few months. However, 18 months later, she was admitted again with tetraparesis and respiratory failure requiring intubation and mechanical ventilation. MRI of the cervical spine revealed a long hyperintense signal in T2W sequence spanning the lower medulla to C8 spinal cord (Figure 2). The lesion was contrast enhancing on T1W sequence. She was diagnosed with a severe transverse myelitis (acute myelitis due to NMO often involves ≥3 contiguous vertebral segments on spinal MRI). Intravenous pulsed steroids and intravenous immunoglobulin was administered. However, the patient succumbed during hospitalization due to a hospital-acquired pneumonia.