Tetanus

Definition

Tetanus is a rare but often fatal disease that affects the central nervous system by causing painful muscular contractions. It begins when tetanus bacteria enter the body, usually through wounds or cuts exposed to contaminated soil. Tetanus is easily preventable through vaccination.

Description

Tetanus is rare in the United States, with nearly all cases occurring in adults who were not vaccinated as children. About 100 cases are reported each year; 70% of these occur in people over the age of 50. Most of the people who die of tetanus infections (75%) are at least 60 years old.

Tetanus causes convulsive muscle spasms and rigidity that can lead to respiratory paralysis and death. It is sometimes called "lockjaw" because one of the most common symptoms is a stiff jaw, unable to be opened. Sometimes, tetanus affects only the part of the body where the infection began, but in almost all of reported cases, it spreads to the entire body. The incubation period from the time of the injury until the first symptoms appear ranges from 2-50 days. Symptoms usually occur within 5-10 days. When symptoms occur early, the chance of death is increased. Tetanus is not contagious.

Causes & symptoms

Tetanus is caused by a bacteria called Clostridium tetani where spores (the dormant form) are found in soil, street dust, and animal feces. Tetanus spores germinate in the body producing a highly poisonous toxin in the blood, spreading to the nervous system. The infection is usually transmitted through deep puncture wounds or cuts or scratches that are not cleaned well. Many people associate tetanus with rusty nails and other dirty objects, but any wound can be a source. Less common ways of getting tetanus are animal scratches and bites, surgical wounds, dental work, and theraputic abortion. Cases have also been reported in people with no known wound or medical condition.

The first symptom of tetanus is often a stiff or "locked" jaw which prevents the patient from opening his/her mouth or swallowing. This is also called trismus and results in a facial expression called a sardonic smile. Stiffness of the neck and other muscles throughout the body and uncontrollable spasms often follow. Sometimes these convulsions are severe enough to cause broken bones. The bacterial toxin (tetanospasmin) affects the nerve endings, causing a continous stimulation of muscles. Other symptoms include irritability, restlessness, loss of appetite, and drooling. People with tetanus that is localized experience pain and tingling only at the wound site and spasms in nearby muscles.

In the underdeveloped world, neonatal tetanus accounts for about one half of tetanus deaths and is related to infection of the umbilical stump in a baby born of an unimmunized mother.

Diagnosis

Tetanus is diagnosed by the clinical symptoms and a medical history that shows no tetanus immunization. Early diagnosis and treatment is crucial to recovery from tetanus.

Treatment

Tetanus is a life-threatening disease that requires immediate hospitalization, usually in an intensive care ward. Treatment can take several weeks and includes antibiotics to kill the bacteria and shots of antitoxin to neutralize the toxin. It also includes antianxiety drugs to control muscle spasms or barbiturates for sedation. In severe cases, patients are placed on an artificial respirator. Recovery can take six weeks or more. After recovery, since the levels of circulating toxin are quite low, the patient must still be adequately immunized against this disease.

Prognosis

Up to 30% of tetanus victims in the United States die. Early diagnosis and treatment improves the prognosis. Neonatal tetanus has a mortality rate of more than 90%.

Prevention

Tetanus is easily preventable through vaccination. All children should have a series of five doses of DTaP, a combined vaccine which offers protection against diphtheria, tetanus, and pertussis, before the age of seven, according to the Centers for Disease Control and Prevention's national immunization guidelines, the Advisory Committee on Immunization Practices, the Committee on Infectious Diseases of the American Academy of Pediatrics, and the American Academy of Family Physicians. Children will not be admitted to school without proof of this and other immunizations.

The DTaP (Diptheria, Tetanus, accellular Pertussis) vaccine should be given at ages 2 months, 4 months, 6 months, 15-18 months, and 4-6 years. DTaP is the preferred vaccine for children up to the age of seven in the United States; it has fewer side effects than DTP and can be used to complete a vaccination schedule begun with DTP. DTaP was first approved by the Food and Drug Administration in September 1996. In December 1996, it was approved for use in infants. Between the ages of 11-13, children should have a booster for diphtheria and tetanus, called Td.

Adults should have a Td booster every 10 years. Statistics from the Centers for Disease Control and Prevention show that fewer than half of Americans 60 years of age and older have antibodies against tetanus. The Centers for Disease Control and Prevention suggests adults may be re-vaccinated at mid-decade birthdays (for example, 45, 55). Adults who have never been vaccinated against tetanus should get a series of three injections of Td over 6-12 months and then follow the 10-year booster shot schedule.

Side effects of the tetanus vaccine are minor: soreness, redness, or swelling at the site of the injection that appear anytime from a few hours to two days after the vaccination and go away in a day or two. Rare but serious side effects that require immediate treatment by a doctor are serious allergic reactions or deep, aching pain and muscle wasting in the upper arms. These symptoms could start from two days to four weeks after the shot and could continue for months.

Keeping wounds and scratches clean is important in preventing infection. Since this organism grows only in the absence of oxygen, the wounds must be adequately cleaned of dead tissue and foreign substances. Run cool water over the wound and wash it with a mild soap. Dry it with a clean cloth or sterile gauze. To help prevent infection, apply an antibiotic cream or ointment and cover the wound with a band-aid. The longer a wound takes to heal, the greater the chance of infection. If the wound doesn't heal or it is red, warm, drains, or swells, consult a doctor.

Following a wound, to produce rapid levels of circulating antibody, a doctor may administer a specific antitoxin (human tetanus immune globulin, TIG) if the individual does not have an adequate history of immunization. The antitoxin is given at the same sitting as a dose of vaccine but at separate sites. Some individuals will report a history of significant allergy to "tetanus shots." In most cases, this occurred in the remote past and was porbably due to the previous use of antitoxin devised from horse serum.

Key Terms

A genus of deadly bacteria that are responsible for tetanus and other serious diseases, including botulism and gangrene from war wounds. It thrives without oxygen.

DTaP

Diphtheria and tetanus toxoids and accellular pertussis combination vaccine.

DTP

Diphtheria, tetanus, and whole-cell pertussis vaccine.

Td

Tetanus and diptheria vaccine.

Toxin

A poisonous substance that flows through the body.

Wound

Any injury that breaks the skin, including cuts, scratches, and puncture wounds.

Further Reading

For Your Information

Periodicals

• "Have You Had Your Shots Yet?" Tufts University Health & Nutrition Newsletter (August 1997): 4.
• Zamalu, Evelyn. "Adults Need Tetanus Shots, Too." FDA Consumer (July/August 1996): 14-18.

  Other

• "Childhood Infections: Tetanus. "The Nemours Foundation of the duPont Hospital for Children and the Nemours Children's Clinic. www.KidsHealth.org (10 Dec 1997).
• "Shots for Safety." National Institute on Aging Age Page. www.nih.gov/nia/health/pubpub/shots.htm (7 December 1997).
• "Taking Care of Cuts, Scrapes, and Minor Wounds: What Mom May Not Have Told You." Mayo Health O@sis @http://www.mayo.ivi.com (9 December 1997).
• "Tetanus & Diphtheria (Td) Vaccine."Centers for Disease Control and Prevention. www.healthtouch.com/level1/leaflets/cdc181.htm (10 December 1997).

Gale Encyclopedia of Medicine. Gale Research, 1999.