A 24-year-old man develops diplopia, gait unsteadiness, and generalized areflexia over 5 days after a diarrheal illness. There is no limb weakness. MRI brain is normal. Which antibody is most likely to be positive?
- A Anti-GM1
- B Anti-GQ1b ✓
- C Anti-GD1a
- D Anti-AQP4
Correct answer: B. Anti-GQ1b
Explanation
The triad of external ophthalmoplegia, cerebellar ataxia, and areflexia defines Miller Fisher syndrome, a variant of Guillain-Barre syndrome. It is strongly associated with IgG antibodies against ganglioside GQ1b, an antigen concentrated in the cranial nerve paranodes and ocular motor nerves. Anti-GM1 and GD1a relate to axonal motor GBS variants such as AMAN, and AQP4 belongs to neuromyelitis optica.
Reference: Bradley's Neurology in Clinical Practice, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.