Area Postrema Syndrome and Long-Segment Myelitis in AQP4-Positive NMOSD
32-year-old woman presents with 2 weeks of intractable vomiting and hiccups followed by acute bilateral leg weakness and urinary retention. She cannot walk without support. MRI of the spine shows a longitudinally extensive T2 hyperintense lesion from C3 to T2; brain MRI shows a lesion in the area postrema. AQP4-IgG is positive. She had a previous episode of right optic neuritis 2 years ago and recovered well. She is not on any maintenance immunotherapy. CSF shows 40 white cells/µL, protein 80 mg/dL, and negative oligoclonal bands. Examination shows bilateral lower limb power 3/5, brisk reflexes, bilateral Babinski signs, and a sensory level at T4. She asks whether this is multiple sclerosis and whether she can plan a pregnancy next year.
1. What is the diagnosis and what acute treatment should she receive?
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This is neuromyelitis optica spectrum disorder (NMOSD) with area postrema syndrome and longitudinally extensive transverse myelitis, supported by AQP4-IgG positivity, negative oligoclonal bands, and a prior optic neuritis episode. It is not typical multiple sclerosis: area postrema involvement, a C3–T2 lesion, and AQP4 positivity are highly specific.
She has severe acute attacks and should receive high-dose intravenous methylprednisolone 1 g daily for 5 days. Because she has marked motor dysfunction and a long myelitis, add plasma exchange early rather than waiting for steroid failure, especially if she does not improve within days. Treat urinary retention, assess for neurogenic bladder, provide VTE prophylaxis, and monitor for infection. Do not use oral steroids alone.
2. Which maintenance therapies are appropriate, and which disease-modifying drugs should be avoided?
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AQP4-positive NMOSD has a relapsing course and requires maintenance immunotherapy. Appropriate options include eculizumab, inebilizumab, satralizumab, rituximab, azathioprine, and mycophenolate mofetil. Choice depends on access, cost, vaccination status, infection risk, and pregnancy plans. Rituximab or azathioprine are common resource-sensitive choices; complement and IL-6 inhibitors are highly effective where available.
Avoid treatments that can worsen NMOSD, including interferon-beta, fingolimod, natalizumab, and alemtuzumab. These are appropriate for some forms of MS but not for AQP4-positive NMOSD. Start maintenance therapy promptly after acute treatment because relapse risk is high and attacks are cumulative.
3. How should pregnancy planning be addressed?
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Pregnancy is possible, but planning is essential. She should wait until she is stable on effective maintenance therapy, ideally for at least 6–12 months after the current attack. Coordinate with maternal-fetal medicine and neurology before conception.
Stop mycophenolate and methotrexate before pregnancy because they are teratogenic. Azathioprine is often continued in pregnancy; rituximab can be considered with timing that minimizes fetal B-cell depletion late in pregnancy; eculizumab and satralizumab require specialist risk-benefit discussion. Counsel that postpartum relapse risk rises, arrange early re-treatment or dose adjustment, and plan contraception until control is achieved. Do not stop immunosuppression abruptly without a replacement plan.