Diptheria

This young patient who did not receive age-appropriate vaccinations has fever, sore throat, and pharyngeal grey patches coalescing into a pseudomembrane, suggesting diphtheria infection.

Diphtheria is caused by toxigenic strains of Corynebacterium diphtheriae, a gram-positive bacillus transmitted via respiratory secretions that largely affects children age <15. Exotoxin released by the bacteria is absorbed systemically and can result in dose-dependent damage to the heart, nervous system, and kidneys. Myocarditis occurs in up to two-thirds of patients; severe cases are associated with complete heart block and heart failure.

Vaccination with diphtheria toxoid significantly reduces the likelihood of infection with toxigenic strains of diphtheria; this not only reduces the risk of developing active infection but also limits asymptomatic carriage of toxigenic strains (causing population-wide declines in prevalence).