Campylobacter Guillain-Barré association — DTM&H MCQ

Correct answer: E — Campylobacter-associated Guillain-Barré syndrome

Campylobacter-associated Guillain-Barre syndrome (option B) is correct because the vignette gives the classic textbook sequence: a diarrhoeal illness from undercooked poultry (the leading source of Campylobacter jejuni), followed two to three weeks later by an ascending, symmetrical weakness with loss of reflexes. This is the molecular mimicry mechanism in which anti-ganglioside antibodies generated against C. jejuni lipo-oligosaccharide cross-react with peripheral nerve gangliosides, producing an acute immune-mediated polyradiculoneuropathy. Campylobacter jejuni is the single most commonly identified antecedent infection in Guillain-Barre syndrome worldwide, and undercooked poultry is its principal reservoir, fitting the exposure history precisely. The delayed onset (weeks, not days) after resolution of the gut infection, combined with progressive ascending weakness and areflexia, is the hallmark clinical pattern taught for this diagnosis. Why the other options are wrong: D. Hypokalaemic periodic paralysis: causes episodic flaccid weakness but is triggered by carbohydrate load or exercise, not preceded by diarrhoeal illness, and reflexes are typically preserved or only transiently reduced, with rapid resolution rather than a progressive ascending course. A. Botulism: produces descending, not ascending, paralysis with early cranial nerve involvement (ptosis, diplopia, bulbar palsy) and is linked to improperly canned or preserved food, not undercooked poultry with a diarrhoeal prodrome. C. Rabies: follows an animal bite or scratch (usually dog in Thailand), has a much longer and variable incubation, and presents with hydrophobia, agitation or ascending paralytic (Guillain-Barre-like) rabies only rarely, without an antecedent diarrhoeal illness. B. Poliomyelitis: causes an asymmetric, purely motor flaccid paralysis without sensory change, typically preceded by a febrile illness rather than diarrhoea specifically, and is now exceedingly rare given global vaccination. Key point: A diarrhoeal illness (especially after poultry) followed weeks later by ascending symmetrical weakness and areflexia is the classic pattern of Campylobacter-triggered Guillain-Barre syndrome.

Reference: RCEMLearning UK, Guillain-Barre Syndrome, https://www.rcemlearning.co.uk/reference/guillain-barre-syndrome/