Diphtheria

- caused by Corynebacterium diphtheriae (Gram positive bacillus)
- produces a toxin which affects myocardium, nervous and adrenal tissues
- most common presentation is with pharyngitis
- areas of grey or white fibrinous exudate coalesce to produce a tough grey-yellow membrane that bleeds when removed (pseudomembrane)
- regional lymphadenopathy produces "bull-neck"
- cutaneous diphtheria may occur, typically ulcer is punched-out with undermined edges covered with a greyish white to brownish adherent membrane
- neuritis frequently follows bulbar distribution
- treatment: anti-toxin (risk of anaphylaxis) and benzylpenicillin 1.2gm QID for 1 week