Neuromyelitis optica spectrum of disorders (NMOSD)

A group of disorders divided into 2 major categories

1. NMOSD with AQP4-IgG
   • At least 1 core clinical characteristic
     1. Optic neuritis
     2. Acute myelitis
     3. Area postrema syndrome (Hiccups, Nausea, or Vomiting)
     4. Acute brainstem syndrome
     5. Narcolepsy or acute diencephalic syndrome
     6. Symptomatic cerebral syndrome with NMOSD-typical brain lesions
   • Positive test for AQP4-IgG
   • Exclusion of alternative diagnoses
2. NMOSD without AQP4-IgG

On imaging 75% present with optic neuritis (Incread T2 signal of optic nerves +/- enhancement), 30% with transverse myelitis (T2 hyperintense spinal cord lesion occupying the entire cross-sectional area of the cord occupying 3-17 segments), dorsal brain stem/area postrema T2 hyperintene lesions, with or without multiple brain parenchymal lesions running parallel to the walls of the ventricles.