Diphtheria

Diphtheria is a potentially fatal infection caused by toxin-producing strains of Corynebacterium diphtheriae, and occasionally by toxigenic Corynebacterium ulcerans and Corynebacterium pseudotuberculosis strains, causing upper respiratory tract or cutaneous disease.

The pathophysiology of diphtheria involves the production of an exotoxin by the pathogen, which inhibits protein synthesis and causes cell death. This leads to the formation of a pseudomembrane in the throat, a characteristic feature of the disease. However, atypical cases without pseudomembrane formation have been reported.

There were 16,611 reported cases of diphtheria globally in 2018. The last confirmed case of respiratory diphtheria in the US was in 2003, and there were 4 reported cases of cutaneous diphtheria between 2015 and 2018.

Risk factors for diphtheria include lack of immunization or partial immunization, as well as living in crowded or unsanitary conditions.

Clinically, diphtheria presents as an acute upper respiratory tract infection. Symptoms include sore throat, fever, and difficulty breathing due to airway obstruction caused by the pseudomembrane. Cutaneous presentations include scaly rash and skin ulcers.

The prognosis of diphtheria is generally good with prompt treatment, which includes the administration of diphtheria antitoxin and antimicrobial therapy. However, severe cases can lead to complications such as myocarditis and neuropathy, which are associated with increased fatality risk.