A 32-year-old woman with known systemic lupus erythematosus presents with acute bilateral lower limb weakness, a sensory level at T6, and urinary retention. MRI spine reveals a longitudinally extensive transverse myelitis spanning four vertebral segments. Serum anti-aquaporin-4 antibody is positive. What is the most likely diagnosis?
- A SLE myelitis
- B Multiple sclerosis
- C Neuromyelitis optica spectrum disorder ✓
- D Spinal cord infarction
Correct answer: C. Neuromyelitis optica spectrum disorder
Explanation
The presence of anti-aquaporin-4 antibody defines neuromyelitis optica spectrum disorder (NMOSD), which can coexist with SLE. Longitudinally extensive transverse myelitis (>3 segments) is characteristic of NMOSD, not typical SLE myelitis. Multiple sclerosis usually causes shorter lesions. Spinal cord infarction is sudden and not associated with this antibody.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.