An 82-year-old woman was admitted for acute gait disturbance and hypoesthesia over 3 days. A general physical examination was normal. Neurological examination revealed muscle weakness of grade 4/5 affecting the right lower limb and grade 1/5 affecting the left lower limb. Deep tendon reflexes were hyperactive in both limbs. Babinski and Chaddock signs were positive on both sides. There was a loss of position and vibration sense combined with hypesthesia below Th10. She had bladder and rectal disturbance. Her Expanded Disability Status Scale (EDSS) score was 8.0. Findings from routine serum studies were normal. Cerebrospinal fluid (CSF) analysis showed a cell count of 2/mL (100% mononuclear cells), normal glucose level, an increased protein concentration of 48 mg/dL, a myelin basic protein (MBP) level of 862 mg/dL (normal range <102 mg/dL), immunoglobulin G (IgG) and albumin ratios of 1.18 (normal range <0.7), and positive oligoclonal bands. Spinal magnetic resonance imaging (MRI) on a T2-weighted image (T2WI) demonstrated two high signals extending from Th1 to Th2 and Th7 to Th9 in the central part of the cord (Fig. , arrows). The lesions showed no contrast enhancement. Brain MRI showed no abnormality. As autoimmune myelitis was suspected, she received high-dose methylprednisolone (1,000 mg/day for 3 days, 3 courses). Her serum was positive for anti-AQP4 antibody (cell-based assay) 17 days after the onset. She was diagnosed with NMOSD and treated with immunoadsorption plasmapheresis and followed up with daily prednisolone (30 mg). Her condition improved and she was able to walk using a walking instrument. Repeat MRI showed marked regression of thoracic lesions 47 days after the onset. She was discharged to another hospital for rehabilitation 50 days after the onset with daily prednisolone (15 mg). Her EDSS score was 5.5.
An 88-year-old woman experienced numbness in her legs and moderate paraparesis with impaired gait since 2 days. Spinal MRI demonstrated a myelon lesion from vertebra T6-9 (Fig. b-c), which was initially attributed to compression myelopathy because of concomitant vertebral disc protrusions. Without specific treatment, she recovered partially and was able to walk with a crutch for >100 m (EDSS 6.0). Her previous medical history was negative for prior potential attacks, but included a transient ischemic attack with dysarthria for <24 h 1.5 years before; cerebral MRI had not shown inflammatory lesions.\nEight months later, she was re-admitted with an anew gait impairment and sensorimotor paraparesis (MRC grade 2–3, EDSS 8.5). MRI demonstrated a new T2 hyperintense myelon lesion from vertebra T10–T12 with central gadolinium enhancement (Fig. d–f). Visual evoked potentials had low amplitudes bilaterally and normal latencies. CSF showed mild lymphomonocytic pleocytosis and positive OCB. Serum AQP4-Ab were positive (1:3200, cell-based immunofluorescence assay), as were antibodies against dsDNA and cardiolipin. Diagnosis of AQP4-Ab positive NMOSD was established, and the first myelon lesion was retrospectively attributed also to NMOSD. Treatment included methylprednisolone 5 × 1 g, a second cycle of 5 × 2 g, and then plasma exchange. She recovered partially (EDSS 7.0). Azathioprine was given up to 150 mg/d (2.2 mg/kg); thiopurine S-methyltransferase activity was normal. After 5 months of therapy, regular blood testing revealed pancytopenia. Azathioprine was stopped, but thrombocytopenia persisted and she died of intestinal bleeding. In addition to azathioprine as a likely cause for bone marrow suppression and thrombocytopenia, she had also developed anti-platelet antibodies.