A 22-year-old woman presents with the inability to smile or frown since waking up around 6 hours ago. She has difficulty in moving her eyes, complains of double vision, and finds it difficult to walk. Close questioning reveals a mild diarrheal episode about 2 weeks ago, which resolved spontaneously. Her surgical and family histories are unremarkable. She does not smoke, only drinks socially, and denies using recreational drugs. She is sexually active, with a single stable partner.
The gadolinium weighted MRI shows bilateral enhancement of the cranial nerves III, VI, and VII. No other abnormalities are present.
Appearance: clear and colorless Cell count: 4 (0-5) Total protein: 450 mg/100 mL (15-60) Glucose: 65 mg/100 mL (50-80) HIV serology: negative EBV serology: negative Anti-Borrelia burgdorferi antibodies: negative
Nerve conduction studies and electromyography of the affected cranial nerves reveal no abnormalities.
Anti-GQ1b antibody levels are markedly elevated.