Classical diphtheria is a severe infectious disease that can be fatal without adequate therapy. It is caused by certain toxin-producing bacteria, Corynebacterium diphtheriae.

In Western countries, usually only sporadic cases are registered. In many regions of the world, however, diphtheria is still endemic, such as the Far and Middle East, South America or Africa.

Human

Transmission occurs mainly via the air (aerogenic) in the form of droplets or through direct contact with respiratory secretions or wound exudates. Vomit or contaminated food (raw milk) or objects can also play a role in transmission.

The classic ports of entry for Corynebacterium diphtheriae are the respiratory tract and the skin. Cutaneous d iphtheria occurs mainly in tropical regions and manifests as poorly healing ulcers (skin ulcers) covered with dirty grey membranes. Respiratory diphtheria begins with sore throat, fatigue, and swelling of the lymph nodes. Pseudomembranes (Greek: "diphthera", dermis) form in the nasopharynx, extend over one or both palatine tonsils and over the remaining tissues of the soft palate, and bleed profusely when removed. The color of these membranes may be white, dirty gray, green, or black. These pseudomembranes can also affect the larynx, trachea, and bronchi, causing respiratory distress that can become life-threatening without immediate action (intubation).

Therapy must be initiated as early as possible (at preliminary clinical diagnosis). It is carried out simultaneously with antibiotics and diphtheria antitoxin (diphtheria serum). With complete basic immunization and regular boosters, the course of the disease is usually mild.

Prevention should begin in childhood. This consists of active immunization with a "toxoid vaccine", an inactivated diphtheria toxin. The vaccine for children is available as a combination vaccine with tetanus and pertussis and poliomyelitis. The immunization should be refreshed every ten years after the basic immunization (e.g. in combination with tetanus).

In 2023, 128 samples were tested at the National Reference Centre for Diphtheria Laboratory. Corynebacterium diphtheriae was detected in 30 samples.

Classical diphtheria is a notifiable disease.

Corynebacteria are gram-positive, facultatively anaerobic, non-spore-forming, irregularly shaped (club-shaped) rod-shaped bacteria (Greek "coryne"). Most representatives of this group are opportunistic germs (i.e. only "pathogenic" under special conditions). Corynebacterium diphtheriae, the causative agent of diphtheria, is of greatest clinical importance, although only toxin-producing strains can cause diphtheria.

In addition to C. diphtheriae, C. ulcerans and C. pseudotuberculosis can also be the cause of diphtheria. Based on morphological and biochemical characteristics, C. diphtheriae is divided into three biotypes: gravis, intermedius, and mitis.

Symptomatology

Cutaneous diphtheria occurs mainly in tropical regions and manifests as poorly healing skin ulcers covered with dirty gray membranes.

Respiratory diphtheria begins after an incubation period of two to five days with sore throat, fatigue, cervical lymph node swelling, and subfebrile temperatures. Adherent pseudomembranes (Greek: "diphthera", dermis) form in the nasopharynx, extend over one or both palatine tonsils and over the remaining tissues of the soft palate, and bleed profusely when cleared. The color of these membranes may be white, dirty gray, green, or black.

These pseudomembranes may also affect the larynx, trachea, and bronchi and cause severe symptoms, such as hoarseness, dyspnea, or cyanosis, which can become life-threatening without immediate action (intubation). As a result of the toxin formation, conduction disorders occur predominantly in the heart and the central nervous system. These manifest themselves as cardiac arrhythmias, conduction disorders of varying degrees as well as acute cardiac insufficiency with circulatory collapse. Primarily, the motor nerves are damaged. Occasionally, sensory nerves are also affected, manifesting as "glove stocking" neuropathy.