Diphtheria

Diphtheria is an acute bacterial infection caused by toxigenic strains of Corynebacterium diphtheriae. The disease is characterised by fibrinous inflammation at the site of pathogen entry (most often in the oropharynx) and severe intoxication of the body, affecting the cardiovascular and nervous systems.

The main danger of diphtheria lies not in local inflammation, but in the powerful exotoxin produced by the bacteria. Once in the bloodstream, the toxin spreads throughout the body and causes damage to vital organs, which can lead to death. Thanks to mass vaccination, this disease is now rare.

Aetiology and pathophysiology

The causative agent is Corynebacterium diphtheriae. Its pathogenicity is due to the ability of some strains to produce diphtheria toxin. The infection is transmitted by respiratory droplets.

Bacteria multiply on the mucous membrane of the oropharynx or larynx, causing epithelial necrosis. Tissue breakdown products, together with fibrin, white blood cells, and bacteria, form a dense, grayish, difficult-to-remove film called a pseudomembrane. The toxin entering the bloodstream causes damage to the heart muscle (myocarditis), peripheral nerves (polyneuropathy) and kidneys.

Clinical Significance

The disease begins with a moderate fever, sore throat and enlarged neck lymph nodes. The key diagnostic feature is the presence of characteristic dense fibrinous deposits on the tonsils, which may spread to the palate, pharynx and larynx.

The most dangerous form is diphtheria of the larynx (diphtheria croup), in which the films can cause asphyxia (suffocation).

At the slightest suspicion of diphtheria, immediate hospitalisation is required. Diphtheria needs urgent treatment:

• Administration of anti-diphtheria serum (antitoxin). This is the main component of treatment aimed at neutralising toxins circulating in the blood.
• Antibacterial therapy. Prescribed to destroy the pathogen at the site of infection.

Prevention is the most effective method of combating diphtheria and consists of routine vaccination of children and re-vaccination of adults (DTP, Td, Td-M vaccines).