TETANUS
DEFINITION
Tetanus (pronounced TET-n-uhss) is an infection of the central nervous system (the brain and spinal cord). The disease is rare, but often fatal. It is caused when the bacterium Clostridium tetani (pronounced claw-STRID-eeum TEHT-uh-nee) enters the body. The bacterium often enters the body through wounds or cuts exposed to soil. Tetanus can easily be prevented through vaccination.
DESCRIPTION
Tetanus is rare in the United States. For many years, a vaccine (pronounced vak-SEEN) has been available to protect against the disease and the vast majority of American children receive the vaccine. A vaccine is a substance that causes the body's immune system to build up resistance to a particular disease. Cases of tetanus usually occur in adults who were never vaccinated against tetanus.
Only about one hundred cases of tetanus are reported in the United States each year. Of this number, about 70 percent occur in people over the age of fifty. Most of those who die of tetanus are over the age of sixty.
Tetanus: Words to Know
- Central nervous system:
- A system of nerve cells in the brain and the spinal cord.
- Clostridium tetani:
- The bacterium that causes tetanus.
- Spasm:
- A contraction of the muscles that can cause paralysis and/or shaking.
- Toxin:
- A poison.
- Vaccine:
- A substance that causes the body's immune system to build up resistance to a particular disease.
Tetanus causes muscular spasms (tightening of the muscles) that can cause paralysis of the respiratory (breathing) system and lead to death. The disease is sometimes called lockjaw. The name comes from a common symptom of tetanus in which the jaw muscles become tight and rigid and a person is unable to open his or her mouth.
Sometimes tetanus affects only one part of the body but usually the infection spreads throughout the body until the entire body becomes paralyzed. The incubation period for tetanus is anywhere from two to fifty days. The incubation period is the time between infection and the first appearance of symptoms. When symptoms occur early, the chance of death is increased.
CAUSES
Tetanus is caused by a bacterium called Clostridium tetani. Bacterial spores (the inactive form of the bacterium) are found in soil, street dust, and animal feces. The spores are transmitted to humans through cuts in the skin. Once inside the body, the spores become active. As they grow, they release a toxin (poison) into the blood stream.
Cuts that have not been thoroughly cleaned are the major source of infection. But the disease can be transmitted in other ways also, such as animal scratches and bites, surgical wounds, and dental work.
SYMPTOMS
The first symptom of tetanus is often a stiff or locked jaw. The patient is unable to open his or her mouth or to swallow. Stiffness soon spreads to the neck and other muscles of the body. The patient often goes into uncontrollable spasms (shaking). The spasms can become so severe as to cause broken bones. Other symptoms of tetanus include irritability, restlessness, loss of appetite, and drooling.
DIAGNOSIS
The symptoms of tetanus are quite distinctive and a doctor can usually diagnose the disease simply by observing the patient. Knowing whether or not the patient has had a tetanus vaccination also helps a doctor make their diagnosis.
EMIL ADOLF VON BEHRING
The vaccine against tetanus was discovered by the German bacteriologist Emil Adolf von Behring (1854–1917) in 1890. Behring was working at the time in the laboratory of the great bacteriologist Robert Koch. One of Behring's colleagues in Koch's laboratory was the Japanese bacteriologist Shibasaburo Kitasato.
Behring and Shibasaburo were especially interested in two terrible diseases, diphtheria and tetanus. Behring had an idea that a vaccine against both diseases might be possible by producing an "antitoxin" against them. He made the antitoxin in the following way:
First, he injected the bacteria that cause tetanus into an experimental animal, such as a rabbit. Then, he removed blood from the infected animal. Next, he injected that blood into a second animal, such as a horse. Finally, he removed blood from the second animal. From this blood, he made a vaccine to be used with humans.
Behring's idea was later developed more fully by his colleague Paul Ehrlich. The vaccine developed by Behring and Ehrlich later became part of the DPT (diphtheria/tetanus/pertussis) vaccine that nearly all young children receive today. For his invention of the vaccine, Behring was awarded the first Nobel Prize in medicine in physiology in 1901.
TREATMENT
Tetanus is a life-threatening disease. It requires immediate hospitalization. Treatment consists of two main steps. First, the patient is given antibiotics to kill the bacteria. Second, injections of antitoxin are also given. An antitoxin is a substance that reacts with and destroys the bacterial toxin.
Patients may also need medication to control muscle spasms. In severe cases, the patient may have to be placed on artificial respiration. Recovery takes six weeks or more. After a patient is better, he or she should receive the tetanus vaccine to protect against future episodes of the disease.
PROGNOSIS
Up to 30 percent of people with tetanus in the United States die. Early diagnosis and treatment improves the chance of survival. The death rate among young babies who develop the disease is more than 90 percent.
PREVENTION
Tetanus can easily be prevented through vaccination. The usual method uses a combination of vaccines that protect against three diseases: tetanus, diphtheria, and pertussis (whooping cough; see whooping cough entry). The vaccine is given in five doses at the ages of two months, four months, six months, fifteen to eighteen months, and four to six years.
Adults should receive a booster shot against tetanus every ten years. A booster shot is a dose of the vaccine that renews a person's resistance to the disease. Adults who have never received a tetanus vaccination should begin one as soon as possible. The adult series consists of three injections over a six to twelve month period.
Side effects of the tetanus vaccine are minor. They include soreness, redness, and swelling at the site of the injection. The symptoms disappear with a few days.
Another way to prevent tetanus infections is to make sure that wounds and scratches are thoroughly cleaned. The tetanus bacterium grows only where there is no oxygen present. So a thorough cleaning of a wound will kill all bacteria. A wound should also be treated with an antibiotic cream and covered with a bandage. Wounds that don't heal should be examined by a doctor.
FOR MORE INFORMATION
Periodicals
Zamalu, Evelyn. "Adults Need Tetanus Shots, Too." FDA Consumer (July/August 1996): pp. 14–18.
Web sites
"Childhood Infections: Tetanus." KidsHealth. [Online] http://www.KidsHealth.org (accessed December 10, 1997).
"Shots for Safety." [Online] http://www.nih.gov/nia/health/pubpub/shots.htm (accessed December 7, 1997).
"Taking Care of Cuts, Scrapes, and Minor Wounds: What Mom May Not Have Told You." [Online] http://www.mayo.ivi.com (accessed December 9, 1997).
"Tetanus & Diphtheria (Td) Vaccine." [Online] http://www.healthtouch.com/level1/leaflet/cdc181.htm (accessed December 10, 1997).