Neuromyelitis Optica (NMO/Devic's Disease)

Neuromyelitis optica spectrum disorder (NMOSD), previously called Devic's disease, is a severe autoimmune condition that primarily attacks the optic nerves (causing optic neuritis) and spinal cord (causing transverse myelitis). It was once thought to be a variant of multiple sclerosis but is now recognized as a distinct disease with different antibodies and treatments.

Understanding NMOSD

In NMOSD, antibodies attack a water channel protein called aquaporin-4 (AQP4), which is abundant in the optic nerves, spinal cord, and certain brain regions. This causes severe inflammation and damage.

Types of NMOSD

AQP4-positive NMOSD

• Aquaporin-4 antibodies present
• Most common form
• Classic clinical features

AQP4-negative NMOSD

• No AQP4 antibodies
• Some have MOG antibodies (now considered separate—MOGAD)
• Others are seronegative

Symptoms

Optic Neuritis

• Often more severe than MS-associated optic neuritis
• More likely bilateral or rapidly sequential
• Higher risk of poor vision recovery
• Pain with eye movement
• Severe vision loss

Transverse Myelitis (Spinal Cord Attack)

• Weakness in legs (or all four limbs)
• Sensory changes (numbness, tingling, burning)
• Bladder and bowel dysfunction
• Often "longitudinally extensive" (affecting ≥3 vertebral segments)
• May be severe with incomplete recovery

Other Features

Area postrema syndrome

• Intractable nausea, vomiting, hiccups
• May be the first symptom
• From attack on brainstem area postrema

Brain lesions

• Less common than MS
• Specific patterns when present

Diagnosis

AQP4 Antibody Testing

• AQP4-IgG (NMO-IgG) blood test
• Positive in 70-80% of NMOSD
• Highly specific when positive
• Cell-based assay most sensitive

MRI Findings

Spinal cord

• Longitudinally extensive transverse myelitis (≥3 segments)
• Central cord involvement

Orbits

• Optic nerve enhancement/swelling
• May involve optic chiasm

Brain

• Often normal or non-specific
• When present, pattern differs from MS

Lumbar Puncture

• CSF analysis
• May show elevated white cells and protein
• Oligoclonal bands less common than MS

Diagnostic Criteria

Requires characteristic clinical features plus either:

• Positive AQP4 antibody, OR
• Specific MRI features and negative AQP4

NMOSD vs. Multiple Sclerosis

Feature	NMOSD	MS
AQP4 antibodies	Positive in 70-80%	Negative
Attacks	Often severe	Usually milder
Optic neuritis	Bilateral, severe	Usually unilateral, better recovery
Spinal cord	Long segment	Short segment
Brain MRI	Often normal	Usually abnormal
Oligoclonal bands	15-30%	90%+
Treatment	Different drugs	Different drugs

This distinction matters because some MS drugs worsen NMOSD.

Treatment

Acute Attack Treatment

High-dose IV steroids

• IV methylprednisolone 1 gram daily for 5 days
• First-line treatment

Plasmapheresis (plasma exchange)

• Used if steroids insufficient
• Removes antibodies from blood
• Often very effective in NMOSD

Attack Prevention (Essential)

Relapse prevention is critical—each attack can cause permanent damage.

First-line options:

• Rituximab—B-cell depleting therapy
• Eculizumab (Soliris)—FDA-approved for AQP4+ NMOSD
• Inebilizumab (Uplizna)—FDA-approved for AQP4+ NMOSD
• Satralizumab (Enspryng)—FDA-approved for AQP4+ NMOSD
• Azathioprine—older but still used
• Mycophenolate—immunosuppressant

Avoid these MS drugs in NMOSD:

• Interferon-beta
• Natalizumab
• Fingolimod
• These may worsen NMOSD

Prognosis

Without Treatment

• High risk of severe disability
• Cumulative damage with each attack
• Significant vision and mobility loss

With Treatment

• Modern treatments have greatly improved outcomes
• Relapse rates significantly reduced
• Earlier diagnosis leads to better outcomes
• Some residual disability from attacks is common

Living with NMOSD

Preventing Relapses

• Take preventive medications as prescribed
• Regular follow-up appointments
• Report new symptoms promptly
• Vaccinations as recommended (avoid live vaccines on immunosuppression)

Managing Symptoms

• Physical therapy for mobility
• Occupational therapy for daily tasks
• Pain management
• Bladder management
• Low vision services if needed

Support Resources

• Guthy-Jackson Charitable Foundation
• National Organization for Rare Disorders (NORD)
• Online support communities

Frequently Asked Questions

Is NMOSD the same as multiple sclerosis?

No. Although they share some features (like optic neuritis), they are distinct diseases with different antibodies, different responses to treatment, and different prognosis. Correct diagnosis is critical because some MS treatments make NMOSD worse.

Will I become blind or paralyzed?

With modern treatment, many people maintain functional vision and mobility. The key is early diagnosis and effective preventive treatment. Each attack can cause permanent damage, which is why prevention is so important.

Can I stop taking medication if I feel fine?

No. Preventive treatment should continue even when you feel well. NMOSD attacks can occur without warning and cause permanent damage. Stopping treatment significantly increases relapse risk.

Is NMOSD hereditary?

NMOSD is not directly inherited, but there may be genetic susceptibility to autoimmune diseases. Having NMOSD doesn't mean your children will have it.

Can I get pregnant with NMOSD?

Pregnancy is possible but requires careful planning. Some medications must be stopped before conception. Relapse risk may change during and after pregnancy. Work closely with your neurologist and obstetrician.

References