Neurology · Year 3 · from Neurology
Case 2: Neuromyelitis Optica Spectrum Disorder (NMOSD)
Patient Demographics
- Age: 35 years
- Sex: Female
- Occupation: Social worker
- Ethnicity: African American
Chief Complaint
"I went blind in both eyes and can't move my legs."
History of Present Illness
The patient presented 10 days ago with severe bilateral vision loss and weakness in both legs that progressed to complete paralysis over 48 hours. She had intractable nausea, vomiting, and hiccups for 2 weeks before the current symptoms (area postrema syndrome). She also developed urinary retention requiring catheterization. Three years ago, she had an episode of bilateral leg weakness and numbness that was diagnosed as "transverse myelitis" and treated with steroids with partial recovery. She has a history of systemic lupus erythematosus (SLE). No similar symptoms in family.
Neurological Examination Findings
Mental Status:
- Alert, oriented, distressed
Cranial Nerves:
- CN II (bilateral):
- Visual acuity: Light perception only in both eyes (severe bilateral visual loss)
- RAPD: Difficult to assess with bilateral involvement
- Color vision: Unable to test
- Fundoscopy: Bilateral disc edema
- Extraocular movements: Intact
- Intractable hiccups during examination
Motor Examination:
- Upper extremities: 5/5 bilateral
- Lower extremities: 0/5 bilateral (complete paraplegia)
- Hypotonic legs (acute stage)
Sensory Examination:
- Complete loss of all sensory modalities below T4 level
- Sensory level at T4
Reflexes:
- Upper extremities: 2+
- Lower extremities: Absent (spinal shock)
- Babinski: Mute initially (may become positive after spinal shock resolves)
Other:
- Urinary retention - Foley in place
NMOSD vs MS: Key Differentiating Features
| Feature | This Patient (NMOSD) | Typical MS |
|---|---|---|
| Optic neuritis | Bilateral, severe | Unilateral, moderate |
| Myelitis | Longitudinally extensive (≥3 segments) | Short segment (<2 segments) |
| Recovery | Poor | Usually good |
| MRI brain | Normal or atypical lesions | Typical periventricular lesions |
| Ethnicity | More common in non-white populations | More common in white populations |
| Associated autoimmunity | Common (SLE, Sjogren's) | Uncommon |
Neuro Workup
- MRI Spine:
- Longitudinally extensive transverse myelitis (LETM): T2 hyperintensity extending from C2-T6 (>3 vertebral segments)
- Central cord predominance
- Enhancement present
- MRI Brain:
- Area postrema lesion (dorsal medulla)
- No typical MS lesions (no periventricular Dawson's fingers)
- MRI Orbits:
- Bilateral optic nerve enhancement and edema, extending to optic chiasm
- Serum:
- Aquaporin-4 (AQP4) antibody (NMO-IgG): POSITIVE - diagnostic
- MOG antibody: Negative
- LP:
- WBC: 85 (neutrophilic pleocytosis - more than MS)
- Protein: 110 (elevated)
- Oligoclonal bands: Absent (unlike MS)
- Labs: ANA positive, anti-dsDNA positive (known SLE)
Diagnosis
Neuromyelitis Optica Spectrum Disorder (NMOSD) - AQP4-IgG seropositive
- IPND 2015 criteria met:
- Core clinical characteristic (optic neuritis + myelitis + area postrema syndrome)
- AQP4-IgG positive
Management
Acute Attack Treatment:
- High-dose IV methylprednisolone 1 g daily for 5 days - initiated immediately
- Plasmapheresis (PLEX) - given severity and poor response to steroids after 3 days
- 5-7 exchanges
- Consider IVIG if PLEX unavailable
Long-term Immunosuppressive Therapy:
- Essential - untreated NMOSD has high relapse rate and accumulating disability
- First-line approved therapies:
- Eculizumab (complement C5 inhibitor)
- Inebilizumab (anti-CD19)
- Satralizumab (anti-IL-6 receptor)
- Off-label options:
- Rituximab (anti-CD20)
- Azathioprine
- Mycophenolate mofetil
- Avoid MS drugs - interferon beta and fingolimod may worsen NMOSD
Symptomatic Management:
- Intractable hiccups: Baclofen, gabapentin, chlorpromazine
- Neurogenic bladder: Intermittent catheterization, anticholinergics
- Neuropathic pain: Gabapentin, pregabalin
- Spasticity: Baclofen, tizanidine
Rehabilitation:
- Intensive inpatient rehabilitation
- PT for mobility, OT for ADLs
- Low vision services for visual impairment
Prognosis:
- More severe attacks and worse recovery than MS
- 50% require walking aid within 5-10 years
- Mortality higher than MS if untreated
Clinical Image
Image Description: Sagittal T2-weighted MRI of the cervical and thoracic spine showing longitudinally extensive transverse myelitis (LETM) spanning more than 3 vertebral segments, characteristic of neuromyelitis optica spectrum disorder.
Attribution: Image from Radiopaedia.org, Case courtesy of Dr. Yuranga Weerakkody. Licensed under CC BY-NC-SA 3.0. Source: https://radiopaedia.org/cases/neuromyelitis-optica-1