What is Diphtheria

Diptheria is caused by the bacterium Corynebacterium diptheriae. Diptheria may be nasal, pharyngeal, laryngeal or cutaneous.

Statistics on Diphtheria

Diptheria occurs worldwide.

Its occurence in the west has fallen due to immunisation, but the disease continues to occur in Russia, Eastern Europe and South-east Asia.

Risk Factors for Diphtheria

The disease is spread by close personal contact with patients with diphtheria or carriers of the disease. It occurs most commonly in the nose and throat, but can also occur in the form of skin infection. The incubation period (the time between infection of an individual and demonstration/manifestation of features of the disease) is 2-7 days.

Progression of Diphtheria

The bacteria primarily infect the nose and throat, although they may initially infect the skin, producing skin lesions. Corynebacterium diphtheriae produces a toxin that causes tissue damage (necrosis) in the immediate area of the infection, usually the nose and throat.

It can also spread via the bloodstream to other organs, where it can cause significant damage. Although the toxin can damage any tissue, the heart and nervous system are most frequently and most severely affected.

Localised infection in the throat and tonsillar area produces a characteristic membrane that is gray to black, tough, and fibrous. This membrane can cause airway obstruction.

Diphtheria may be mild and unrecognised or it may become progressive. If toxin enters the bloodstream, the patient may develop inflammation of the heart muscle (myocarditis), which is the most common and most worrisome complication. Toxic effects on the nervous system may also cause temporary paralysis.

How is Diphtheria Diagnosed?

A diagnosis must be made on clinical grounds because therapy is usually too urgent to wait for the results of clinical studies and toxin production.

Prognosis of Diphtheria

The disease can be fatal but is preventable by active immunisation in childhood followed by booster doses.

How is Diphtheria Treated?

Prior to treatment the patient should be questionned about allergic conditions (e.g. asthma and hay fever) and previous antitoxin administration.

The patient should be isolated and bed rest. Antitoxin therapy must be given promptly to prevent further fixation of the toxin on tissue receptors. An initial test dose of antitoxin should be administered to exclude any allergic reaction. Then, depending on the severity of the disease 20,000 to 100,000 units of horse-serum antitoxin should be administered intramuscularly.

Benzylpenicillin 1.2g four times daily for 1 week should also be administered concurrently to eliminate the bacterium and thereby remove the source of toxin production.

Diphtheria References

  1. Haslett C et al, editors. Davidson’s principles and practice of medicine. 19th ed. Edinburgh ; New York : Churchill Livingstone; 2002.
  2. Kumar P, Clark M. Clinical Medicine. 5th Ed. Edinburgh: WB Saunders; 2002.