diphtheria
The definitions used in this glossary of terminology either have been provided by the authors of the articles, or have been extracted wholly or in part, or paraphrased from the following sources: The American Medical Association Encyclopedia of Medicine, Charles B. Clayman, MD, Medical Editor, Random House, New York, 1989; Biotechnology from A to Z, 2d Edition, William Bains, Oxford University Press, New York, New York, 2002; A Dictionary of Genetics, 6th Edition, Robert C. King and William D. Stansfield, Oxford University Press, New York, New York, 2002; Dorland's Illustrated Medical Dictionary, 29th and 30th Editions, W. B. Saunders Company, Philadelphia, 2000, 2003; Genes VII, Benjamin Lewin, Oxford University Press, New York, New York, 2000; The Gale Encyclopedia of Genetic Disorders, Volumes I and II, Stacey L. Blachford, Ed., Thomson Learning, New York, New York, 2002; The Merriam-Webster Dictionary, Merriam-Webster, Inc., Springfield, Massachusetts, 1997; Molecular Biology of the Cell, 3rd Edition, Bruce Alberts, et al., Garland Publishing, 1994; The Random House Dictionary of the English Language, Unabridged Edition, 1966; Webster's Ninth New Collegiate Dictionary, 1991.
DEFINITION:
- diphtheria
-
An acute bacterial illness that causes a sore throat and a fever, and sometimes causes more serious or even fatal complications.
Cause
Diphtheria is caused by the bacillus corynebacterium diphtheriae. It may live in the skin or in the nose of a person immune to the disease (known as a "carrier") or, during an infection, may multiply in the throat or skin. Serious complications are caused by a toxin released by the bacterium into the bloodstream.
Symptoms
When a nonimmune person is infected by the bacterium spread from a carrier, the bacterium usually multiplies in the throat, giving rise to a membrane that appears over the tonsils and may spread over the palate or downward to the larynx (voice box) and trachea (windpipe). This may cause breathing difficulties and a husky voice. Other symptoms include enlarged lymph glands in the neck, an increased heart rate, and mild fever. Sometimes, an infection is confined to the skin, where it may cause no more than a few yellow spots or sores with an appearance similar to impetigo.
Life-threatening symptoms develop only in nonimmune people and are caused by the bacterial toxin. Occasionally, victims collapse and die within a day or so of getting the throat infection. More often they are recovering from this condition when heart failure or paralysis of the throat or limbs develops. These later complications can occur up to seven weeks after onset of infection in the throat. If victims survive the disease they make a complete recovery.
Prevention
In the US and other developed countries, the triple vaccine, also known as the DPT vaccine (against diphtheria, pertussis, and tetanus), is given routinely to children in the first year of life. The practice of immunizing against diphtheria must continue, despite the extreme rarity of the disease in these countries, because carriers can arrive from developing countries at any time; if large numbers of children were not immune, there could be a disastrous epidemic.
Those traveling to poor, developing countries who are in doubt as to whether they were immunized against diphtheria as children should have their immune status checked or simply be vaccinated.
Treatment
Penicillin kills diphtheria organisms in the throat, but is ineffective against the toxin in the blood. If the disease is suspected, an antitoxin (derived from the blood of immunized horses) must be given as soon as possible in addition to penicillin. If severe breathing difficulties develop in the patient, a tracheostomy (surgical introduction of a breathing tube into the windpipe) may be necessary.
Victims are kept in isolation until no diphtheria bacilli can be detected in the nose and throat (by swabs taken on six consecutive days).
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