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Tetanus |
| Tetanus Classification and external resources |
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| Muscular spasms in a patient suffering from tetanus. Painting by Sir Charles Bell, 1809. | |
| ICD-10 | A33.-A35. |
| ICD-9 | 037, 771.3 |
| DiseasesDB | 2829 |
| MedlinePlus | 000615 |
| eMedicine | emerg/574 |
| MeSH | D013742 |
Tetanus is a medical condition that is characterized by a prolonged contraction of skeletal muscle fibres. The primary symptoms are caused by tetanospasmin, a neurotoxin produced by the Gram-positive, obligate anaerobic bacterium Clostridium tetani. Infection generally occurs through wound contamination, and often involves a cut or deep puncture wound. As the infection progresses, muscle spasms in the jaw develop, hence the common name, lockjaw. This is followed by difficulty in swallowing and general muscle stiffness and spasms in other parts of the body.1 Infection can be prevented by proper immunization and by post-exposure prophylaxis.2
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The "spatula test" for tetanus involves touching the posterior pharyngeal wall with a sterile, soft-tipped instrument, and observing the effect. A positive test result is the involuntary contraction of the jaw (biting down on the "spatula"), and a negative test result would normally be a gag reflex attempting to expel the foreign object.
A short report in The American Journal of Tropical Medicine and Hygiene states that in a patient research study, the spatula test had a high specificity (zero false-positive test results) and a high sensitivity (94% of infected patients produced a positive test result).3
The wound must be cleaned. Dead and infected tissue should be removed by surgical debridement. Metronidazole treatment decreases the number of bacteria but has no effect on the bacterial toxin. Penicillin was once used to treat tetanus, but is no longer the treatment of choice, owing to a theoretical risk of increased spasms. However, its use is recommended if metronidazole is not available. Passive immunization with human anti-tetanospasmin immunoglobulin or tetanus immune globulin is crucial. If specific anti-tetanospasmin immunoglobulin is not available, then normal human immunoglobulin may be given instead. All tetanus victims should be vaccinated against the disease or offered a booster shot.
Mild cases of tetanus can be treated with:
Severe cases will require admission to intensive care. In addition to the measures listed above for mild tetanus:
Drugs such as diazepam or other muscle relaxantscitation needed can be given to control the muscle spasms. In extreme cases it may be necessary to paralyze the patient with curare-like drugs and use a mechanical ventilator.
In order to survive a tetanus infection, the maintenance of an airway and proper nutrition are required. An intake of 3500-4000 Calories, and at least 150g of protein per day, is often given in liquid form through a tube directly into the stomach, or through a drip into a vein. This high-caloric diet maintenance is required because of the increased metabolic strain brought on by the increased muscle activity.
Tetanus can be prevented by vaccination.4 The CDC recommends that adults receive a booster vaccine every ten years, and standard care practice in many places is to give the booster to any patient with a puncture wound who is uncertain of when he or she was last vaccinated, or if he or she has had fewer than 3 lifetime doses of the vaccine. The booster cannot prevent a potentially fatal case of tetanus from the current wound, however, as it can take up to two weeks for tetanus antibodies to form.5 In children under the age of seven, the tetanus vaccine is often administered as a combined vaccine, DPT/DTaP vaccine, which also includes vaccines against diphtheria and pertussis. For adults and children over seven, the Td vaccine (tetanus and diphtheria) or Tdap (tetanus, diphtheria, and acellular pertussis) is commonly used.4
Tetanus is a global health problem, as C. tetani spores are ubiquitous. The disease occurs almost exclusively in persons who are unvaccinated or inadequately immunized.1 Tetanus occurs worldwide but is more common in hot, damp climates with soil rich in organic matter. This is particularly true with manure-treated soils, as the spores are widely distributed in the intestines and faeces of many non-human animals such as horses, sheep, cattle, dogs, cats, rats, guinea pigs, and chickens. In agricultural areas, a significant number of human adults may harbour the organism. The spores can also be found on skin surfaces and in contaminated heroin.2
Tetanus – particularly the neonatal form – remains a significant public health problem in non-industrialized countries. There are about one million cases of tetanus reported worldwide annually, causing an estimated 300,000 to 500,000 deaths each year.2
In the United States, approximately 100 people become infected with tetanus each year, and there are about five deaths from tetanus each year.6 Nearly all of the cases in the United States occur in unimmunized individuals or individuals who have allowed their inoculations to lapse,6 whereas most cases in developing countries are due to the neonatal form of tetanus.
Tetanus is the only vaccine-preventable disease that is infectious but is not contagious.62
Tetanus is often associated with rust, especially rusty nails, but this concept is somewhat misleading. Objects that accumulate rust are often found outdoors, or in places that harbour anaerobic bacteria, but the rust itself does not cause tetanus nor does it contain more C. tetani bacteria. The rough surface of rusty metal merely provides a prime habitat for a C. tetani endospore to reside, and the nail a means to puncture skin and deliver endospore into the wound. An endospore is a non-metabolising survival structure that begins to metabolise and cause infection once in an adequate environment. Because C. tetani is an anaerobic bacterium, it and its endospores will thrive in an environment that lacks oxygen. Hence, stepping on a nail (rusty or not) may result in a tetanus infection, as the low-oxygen (anaerobic) environment of a puncture wound provides the bacteria with an ideal breeding ground.
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Wikimedia Commons has media related to: Tetanus |
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