Rationale: Anti-GQ1b antibody syndrome refers to a distinct variant of Guillain- Barré syndrome. Involvement of the optic nerve in anti-GQ1b antibody syndrome is extremely rare.
Patient concerns: Here, we report a case of anti-GQ1b antibody syndrome presenting with visual deterioration as the initial symptom. A 73-year-old man presented with a 5-day history of bilateral blurred vision and ptosis. He had a previous history of diarrhea starting 10 days before admission. Physical examination showed visual deterioration, ophthalmoplegia, and peripheral facial paralysis. Testing of both serum and cerebrospinal fluid was positive for anti-GQ1b immunoglobulin G antibodies and negative for anti-aquaporin 4antibodies.
Diagnosis: Anti-GQ1b antibody syndrome.
Interventions: The patient was treated with intravenous methylprednisolone and human immunoglobulin.
Outcomes: After a 20-day follow-up, the patient's condition took a favorable turn.
Lessons: This case reminds us that anti-GQ1b antibody syndrome should be suspected in patients with visual deterioration and preceding infection.