Neuromyelitis optica spectrum disorder
Neuromyelitis optica spectrum disorder is a recurrent, severe antibody-mediated demyelinating disease of the optic nerves and spinal cord, usually driven by aquaporin-4 IgG, that mimics multiple sclerosis. Diagnosis rests on optic neuritis or transverse myelitis, a longitudinally extensive cord lesion of 3 or more vertebral segments, and serum aquaporin-4 IgG; attacks are treated with IV methylprednisolone or plasma exchange, and antibody-positive patients need long-term immunosuppression.
- Topic reviewThe full article, organized the way the exam asks it.
- ABIM-format MCQsVignettes with an explanation for every wrong answer.
- Key factsThe numbers and thresholds worth memorizing, up front.
- AI tutorMedBrain answers the question you're stuck on.
What this article covers
- Overview
Definition: neuromyelitis optica spectrum disorder (NMOSD) is a recurrent, severe, antibody-mediated inflammatory demyelinating disease of the central nervous system that targets mainly the optic nerves and spinal cord.
- Epidemiology
Inflammatory myelopathy group: NMOSD belongs, with MS and sarcoidosis, to the inflammatory disorders that are the most common causes of noncompressive myelopathy.
- Risk factors
AQP4-IgG seropositivity: the presence of the antibody itself predicts recurrent attacks.
- Pathophysiology
Antibody binding: AQP4-IgG binds the aquaporin-4 water channel on astrocytes, and the antibody has a direct pathogenic role rather than being a bystander marker.
- Clinical features
Severe optic neuritis: visual acuity loss that worsens over days, pain on eye movement, loss of color vision, and visual field defects; involvement is often bilateral, unlike the usually unilateral…
- Differential diagnosis
Multiple sclerosis: usually unilateral optic neuritis, short segmental cord lesions, multiple brain white-matter lesions, CSF oligoclonal bands in 90% to 95%, and normal or slightly elevated CSF leukocytes.
- Diagnosis
Diagnostic criteria (three components): the diagnosis is established when all three are present: severe optic neuritis, transverse myelitis, or both; MRI showing a contiguous spinal cord lesion…
- Management
First, treat the acute attack with high-dose glucocorticoids: methylprednisolone 1 g IV once daily for 3 to 5 days, started as soon as the attack is recognized.
- Complications
Permanent visual loss: severe or recurrent optic neuritis can leave fixed blindness in one or both eyes.
- Prognosis
Worse than MS: NMOSD carries a more severe and aggressive course, with each attack able to cause permanent disability.
- Prevention
Start maintenance immunosuppression after the first attack in AQP4-IgG positive patients: do not wait for a second attack, since antibody positivity alone predicts relapse.
Read the whole article
Subscribing to Internal Medicine opens every article, the full question bank and MedBrain, on the web, iPhone and Android.
Related articles
- Multiple sclerosis
Multiple sclerosis is an autoimmune, demyelinating CNS disorder causing optic neuritis, myelitis, and brainstem/cerebellar syndromes separated in space and time. Diagnosis uses the McDonald MRI-based criteria; acute relapses are treated with high-dose glucocorticoids, and disease-modifying therapy (interferon beta, glatiramer, or a higher-efficacy agent such as ocrelizumab or natalizumab) is started early to prevent relapse and disability accumulation.
- MOG antibody-associated disease
MOG antibody-associated disease is an antibody-mediated inflammatory demyelinating disorder of the central nervous system, directed at myelin oligodendrocyte glycoprotein, that presents as optic neuritis, transverse myelitis, or acute disseminated encephalomyelitis and encephalitis, with a monophasic or recurrent, steroid-responsive course. It is confirmed by MOG antibody testing in a compatible syndrome, separated from multiple sclerosis by limited brain involvement, longitudinally extensive cord lesions, and marked CSF pleocytosis; attacks are treated with high-dose IV methylprednisolone and plasma exchange, and recurrent disease with long-term immunosuppression.
- Optic neuritis
Optic neuritis is inflammatory demyelination of the optic nerve, usually a presenting event of multiple sclerosis, causing subacute painful monocular vision loss with a relative afferent pupillary defect. Confirm with MRI orbits/brain and treat with IV methylprednisolone followed by an oral prednisone taper, never oral prednisone alone.
- Transverse myelitis
Transverse myelitis is inflammation across one or more contiguous spinal cord segments causing subacute weakness, a sensory level, and bladder or bowel dysfunction; diagnosis requires spinal MRI showing cord enhancement or CSF inflammation with exclusion of compressive and infectious causes, and idiopathic disease is treated with high-dose intravenous methylprednisolone.
- Acute disseminated encephalomyelitis
Acute disseminated encephalomyelitis is a monophasic, often postinfectious, immune-mediated demyelinating illness that produces large, diffuse inflammatory lesions of the brain and spinal cord. Fever and encephalopathy with multifocal deficits separate it from multiple sclerosis; treatment is high-dose IV methylprednisolone, with plasma exchange for steroid-refractory disease, after infection is excluded.
- Sjogren syndrome
Sjogren syndrome is a systemic autoimmune exocrinopathy in which lymphocytic infiltration of the lacrimal and salivary glands causes keratoconjunctivitis sicca and xerostomia, occurring alone (primary) or alongside another rheumatologic disease such as rheumatoid arthritis or lupus (secondary). Diagnosis combines the anti-Ro (SSA) and anti-La (SSB) antibody panel, objective dryness testing, and labial salivary gland biopsy under the 2016 ACR/EULAR classification criteria. Management centers on sicca-directed therapy, pilocarpine or cevimeline for xerostomia and topical cyclosporine for keratoconjunctivitis, with hydroxychloroquine or immunosuppression for extraglandular disease.