A 35-year-old woman develops ascending weakness starting in the legs over 2 days after a diarrheal illness 2 weeks ago. She now has bilateral facial diplegia, areflexia, and sensory loss. CSF shows albumino-cytological dissociation (protein 180 mg/dL, cells 3/µL). Nerve conduction studies show reduced CMAP amplitudes with prolonged distal latencies and absent F waves. Which antibody is associated with the most severe axonal variant of GBS?
- A Anti-ganglioside GM1 IgG and GD1a antibodies ✓
- B Anti-GQ1b IgG antibody
- C Anti-GD3 antibody
- D Anti-MuSK antibody
Correct answer: A. Anti-ganglioside GM1 IgG and GD1a antibodies
Explanation
Anti-GM1 and anti-GD1a IgG antibodies are associated with acute motor axonal neuropathy (AMAN) and acute motor and sensory axonal neuropathy (AMSAN) — the severe axonal variants of GBS often triggered by Campylobacter jejuni infection. These antibodies target gangliosides on the nodes of Ranvier in motor axons. Anti-GQ1b IgG is associated with Miller Fisher syndrome (ophthalmoplegia, ataxia, areflexia) and the Bickerstaff brainstem encephalitis spectrum. Anti-MuSK is found in myasthenia gravis, not GBS.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.