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MCQs in Tropical Medicine

Rob Skelly DTM+H FRCP

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Answer 93 Diphtheria

False a. "bull neck" is diagnostic
True b. it is caused by Gram positive bacilli
True c. toxin absorption is greatest in pharyngeal disease
True d. palatal paralysis is a recognised complication
True e complete heart block is a manifestation of toxin-induced myocarditis

Corynebacterium diptheriae is a Gram positive, toxin-producing bacillus. the toxin is responsible for the manifestations of the disease and diphtheria toxoid immunisation, usually given in childhood, protects against the dangerous effects of infection.

Of the three strains, gravis and intermedius produce more severe infection, and mitis milder infection.

Classically there is a grey pharyngeal membrane. The "bull neck" appearance is due to soft tissue oedema and cervical lymphadenopathy. Other causes of cervical lymphadenopathy may cause a superficially similar appearance .

1. watch airway
2. benzylpenicillin for 2 weeks
3. antitoxin
4. observe for complications
5. contact tracing
6. isolation.

Copyright: Rob Skelly 2006