Table 2

 Diagnostic criteria for neuromyelitis optica

Diagnosis requires all absolute criteria and one major or two minor supportive criteria.
Absolute criteria
    Optic neuritis
    Acute myelitis
    No evidence of clinical disease outside optic nerve or spinal cord
Supportive criteria
        Negative brain MRI at onset
        Spinal MRI with signal abnormalities >3 vertebral segment lengths
        CSF pleocytosis >50 cells/mm3 or >5 neutrophils/mm3
        Bilateral optic neuritis
        Severe optic neuritis with visual acuity worse than 6/60 in at least
        one eye
        Severe, fixed, attack related weakness (MRC grade ⩽2) in one or
        more limbs