Synopsis
Recognise the distinctive optic-nerve, spinal-cord and area-postrema syndromes of NMOSD, secure the correct antibody diagnosis and escalate attacks before irreversible disability accumulates.
- Neuromyelitis optica spectrum disorder is an autoimmune astrocytopathy, most often associated with serum aquaporin-4 immunoglobulin G; it is not simply a severe form of multiple sclerosis.
- Core presentations are severe or bilateral optic neuritis, acute myelitis, area-postrema syndrome, an acute brainstem syndrome, symptomatic diencephalic disease and characteristic cerebral syndromes.
- Longitudinally extensive transverse myelitis spans three or more vertebral segments, although an early or treated lesion can be shorter and a normal first scan does not settle a convincing case.
- Area-postrema inflammation causes otherwise unexplained intractable hiccups, nausea or vomiting and may precede optic-nerve or cord involvement by weeks.
- Request a serum AQP4-IgG cell-based assay before immunotherapy when feasible; test for MOG-IgG in an appropriate AQP4-negative phenotype because MOG-associated disease has different implications.
- A severe attack is treated urgently with high-dose intravenous corticosteroid and early plasma exchange when response is incomplete or the deficit is profound; arrangements vary between specialist centres.
- AQP4-positive disease is usually relapsing, so one confirmed attack commonly prompts discussion of relapse-prevention immunotherapy rather than watchful waiting for a second event.
- Some multiple-sclerosis disease-modifying treatments are ineffective or potentially harmful in NMOSD; diagnostic precision must precede long-term treatment selection.
- Recovery, pain, spasticity, bladder dysfunction, vision rehabilitation, mood, pregnancy and vaccination all need planned multidisciplinary follow-up alongside immunosuppression safety.
- The regimens below describe common UK specialist practice; acute dosing, exchange schedules and maintenance biologics require local neuroimmunology protocols.
Key red flags
Eye pain is followed by marked monocular or bilateral visual loss, impaired colour perception and a relative afferent pupillary defect. Chiasmal involvement, poor recovery or recurrent attacks should raise NMOSD above typical MS-associated optic neuritis.
Subacute bilateral weakness, a sensory level, band-like pain and bladder or bowel dysfunction evolve over hours to days. High cervical lesions may cause diaphragmatic weakness and demand respiratory monitoring.
Persistent hiccups or vomiting has no adequate gastrointestinal explanation and may coexist with vertigo, dysphagia or an upper-cervical sensory disturbance. Recognising this pattern prevents repeated abdominal investigations while inflammation advances.
Investigation priorities
Locate active optic-nerve, medullary, cerebral and cord inflammation while excluding compression and vascular or neoplastic alternatives.
Management branches
New objective optic, spinal, brainstem or cerebral deficit compatible with inflammatory relapse.
- Admit when vision, walking, respiration, swallowing or sphincter function is threatened; document a neurological baseline and arrange urgent MRI while excluding compression, vascular disease and infection.
- After senior neuroinflammatory agreement, give high-dose intravenous methylprednisolone, commonly 1 g daily for three to five days in adults, with glucose, blood-pressure, gastric and infection precautions under local policy.
- Escalate early to therapeutic plasma exchange, often five to seven exchanges, if the attack is severe or steroid response is insufficient; do not postpone referral until the steroid course is long finished.
- Begin rehabilitation, thromboprophylaxis, pressure-area care and management of pain, spasticity, bladder and bowel function in parallel rather than after immunotherapy ends.