Neuromyelitis optica spectrum disorders

Antibodies
Anti-AQP4 and anti-MOG antibodies occur together very rarely. Only 10 patients of the 1291 patients with anti-MOG antibodies also had anti-AQP4.

If serum anti-MOG antibodies are negative, they may rarely be positive in CSF samples in seronegative patients.

Signs and symptoms

 * Optic neuritis
 * Acute myelitis
 * Area postrema syndrome: otherwise unexplained hiccups or nausea and vomiting. While this is common in AQP4-IgG disease, it is far less common in anti-MOG disease.
 * Acute brainstem syndrome
 * Symptomatic narcolepsy or acute diencephalic clinical syndrome with NMOSD-typical diencephalic MRI lesions
 * Symptomatic cerebral syndrome with NMOSD-typical brain lesion

IV Methylprednisolone
Treatment of IV methylprednisolone (IVMP) 1,000 mg IV daily for 3-5 daysfollowed by oral prednisone (1 mg/kg/d) is warranted for acute attacks of optic neuritis. Early treatment of optic neuritis is key. In one study of 27 patients with either AQP4 Ab or MOG Ab optic neuritis, treatment with IVMP later than 4 days after onset was highly associated with failure to regain 20:20 vision (OR 8.33, 95% CI 1.47-47.22). Treatment with IVMP later than 7 days was highly associated with failure to regain 20:30 vision (OR 10.0, 95% CI 1.39-71.86).

Satralizumab
This medication is an IL-6 receptor blocker blocking IL-6 signaling that causes inflammation. In a small randomized double-blind trial of 83 patients with NMOSD randomly assigned to satralizumab or placebo, significantly fewer relapses were noted in the satralizumab group (20%) vs the placebo group (43%), HR 0.38 (95% CI 0.16-0.88), with this result being significant for those with anti-AQP4 antibodies but not in the antibody negative patients. However there were no differences in functional outcomes or mortality.