Medicine · Neurology (Stroke, Epilepsy, Parkinson's, MS, MG, GBS, Meningitis)

A 22-year-old man presents with ascending paralysis, absent deep tendon reflexes, and albuminocytological dissociation on CSF analysis 2 weeks after a Campylobacter jejuni gastroenteritis. Nerve conduction studies show absent F-waves and reduced CMAP amplitudes with relatively preserved conduction velocities. This variant of GBS is:

  • A Acute motor axonal neuropathy (AMAN)
  • B Acute inflammatory demyelinating polyneuropathy (AIDP)
  • C Miller Fisher syndrome
  • D Acute sensory neuropathy
Correct answer: A. Acute motor axonal neuropathy (AMAN)

Explanation

AMAN (acute motor axonal neuropathy) is the GBS variant strongly associated with Campylobacter jejuni infection and anti-GM1/GD1a ganglioside antibodies. Nerve conduction studies in AMAN show predominantly reduced CMAP amplitudes (axonal pattern affecting motor fibers only) with relatively preserved sensory nerve action potentials and normal/near-normal conduction velocities, distinguishing it from AIDP (where demyelination causes prolonged conduction velocities and absent F-waves with slowing). Miller Fisher syndrome features 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.

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