Tetanus

Tetanus is a serious and often fatal disease caused by the neurotoxin tetanospasmin which is produced by the Gram-positive, obligate anaerobic bacterium Clostridium tetani. Tetanus also refers to a state of muscle tension. more...

It was first documented by Hippocrates, and records dating back to the 5th century BCE provide countless clinical observations of the disease. However, the etiology of the disease was not discovered until 1884 by Carle and Rattone. Passive tetanus immunization was first implemented during World War I.

Bacilli of C. tetani can be found in soil (especially agricultural soil), and the intestines and feces of horses, sheep, cattle, rats, dogs, cats, guinea pigs, and chickens. Spores are found in manure-treated soil, skin surfaces (of both animals and humans), under nail-beds, and in contaminated heroin.

Types

There are four different clinical forms of tetanus: local (uncommon), cephalic (rare), generalized (most common), and neonatal (a common cause of infant mortality in underdeveloped countries). Generalized tetanus accounts for 80% of tetanus cases.

Symptoms

The incubation period for tetanus is 3 days to as long as 15 weeks (with the average being about 8 days) . For neonates, the incubation period is 4 to 14 days, with 7 days being the average. Most of the time, the further the wound is from the central nervous system, the longer the incubation period. Incubation period length and likelihood of death are inversely proportional; a deep, contaminated wound that allows the bacteria to flourish and causes a quick, aggressive infection is much more life-threatening than a shallower, less-contaminated wound that causes milder symptoms to appear days or weeks later.

The first sign of tetanus is a mild jaw muscle spasm called lockjaw (trismus), followed by stiffness of the neck and back, risus sardonicus, difficulty swallowing, and muscle rigidity in the abdomen. The stiffness and spasming of muscles expands throughout the body inferiorly, and can be so powerful that they cause muscle tears and even fractures. Typical signs of tetanus include an increase in body temperature by 2 to 4°C, diaphoresis (excessive sweating), an elevated blood pressure, and an episodic rapid heart rate. Spasms and muscle contraction last for 3 to 4 weeks, and complete recovery may take months. About 30% of tetanus victims die, most of whom are elderly patients. In developing countries, the mortality rate may be as high as sixty percent.

Complications of the disease include spasms of the larynx (vocal cords), accessory muscles (chest muscles used to aid in breathing), and the diaphragm (the primary breathing muscle); fractures of long bones secondary to violent muscle spasms; and hyperactivity of the autonomic nervous system.

Treatment

The wound must be cleaned. Penicillin and metronidazole will help decrease the amount of bacteria but they have no effect on the toxin produced by the bacteria. Human anti-tetanospasmin immunoglobulin should be given. Diazepam and DTaP vaccine booster are also given.

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