Paediatric Infections · NEET PG Preparation Paediatrics
A 4-year-old unimmunized child is brought to the emergency department with a 2-day history of a sore throat, low-grade fever, and progressive respira…
Practice question from Paediatric Infections (NEET PG Preparation Paediatrics), with the correct answer and a step-by-step solution.
medium · MCQ · Q-3B6D87
A 4-year-old unimmunized child is brought to the emergency department with a 2-day history of a sore throat, low-grade fever, and progressive respiratory distress. Examination reveals a pale child with a thick, adherent grayish-white pseudomembrane covering the tonsils and pharynx, which bleeds upon attempted removal. There is marked cervical lymphadenopathy giving a 'bull-neck' appearance. What is the primary mechanism of pathogenesis of the most likely causative organism?
- A.Inhibition of protein synthesis via ADP-ribosylation of elongation factor 2 (EF-2)Correct answer
- B.Activation of adenylate cyclase leading to increased intracellular cAMP
- C.Cleavage of synaptobrevin preventing inhibitory neurotransmitter release
- D.Inhibition of acetylcholine release at the neuromuscular junction
Solution
The clinical presentation is classic for diphtheria, caused by Corynebacterium diphtheriae. The diphtheria exotoxin is an A-B toxin that inhibits protein synthesis by catalyzing the ADP-ribosylation of elongation factor 2 (EF-2). Option B describes pertussis toxin or cholera toxin. Option C describes tetanus toxin. Option D describes botulinum toxin.
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