A 45-year-old woman presents with ascending limb weakness over 2 weeks. She recently had Campylobacter jejuni gastroenteritis. CSF shows albuminocytologic dissociation. Nerve conduction studies reveal prolonged distal motor latencies, absent F-waves, and low-amplitude motor responses. The most likely subtype of Guillain-Barré syndrome is:

• A Miller Fisher syndrome
• B Acute motor axonal neuropathy (AMAN)
• C Acute motor and sensory axonal neuropathy (AMSAN)
• D Acute inflammatory demyelinating polyradiculoneuropathy (AIDP) ✓

Explanation

The NCS pattern described — prolonged distal motor latencies, absent F-waves, and relatively preserved SNAP amplitudes with low CMAP amplitude — is consistent with AIDP (demyelinating pattern), the most common GBS subtype in Western countries. AMAN (associated with C. jejuni and anti-GM1/GD1a antibodies) shows an axonal pattern with reduced CMAP but normal distal latencies and preserved sensory responses. AMSAN affects both motor and sensory axons. Miller Fisher syndrome presents with ophthalmoplegia, ataxia, and areflexia with anti-GQ1b antibodies.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.