Tetanus results from a toxin produced by the anaerobic bacteria Clostridium tetani. The toxin makes muscles become rigid and contract involuntarily (spasm).
Although rare in the United States, tetanus kills up to 500,000 people each year, mainly in developing countries.
Clostridium tetani is present in soil and animal feces and can live there for years. Tetanus bacteria may enter the body through
Sometimes the injury is so small that people do not even go to a doctor. Injuries that involve dead skin (such as burns, frostbite, gangrene, or crush injuries) are more likely to cause tetanus. When oxygen is absent in dead tissue, tetanus spores reproduce and produce a toxin that travels through the body and prevents nerves from sending signals to other nerves.
Occasionally, tetanus results when the uterus is damaged during an induced abortion or childbirth. In developing countries, soil contamination of the stump of the umbilical cord can cause tetanus in newborns.
Vaccination during childhood plus booster doses every 10 years during adulthood can prevent tetanus. Thus, the infection occurs mainly in people who have not been vaccinated or not kept their vaccinations up to date. This situation is more common in developing countries. In the United States, tetanus is a risk for people who inject drugs. The risk is also higher for older people but usually only if they have never been vaccinated.
Tetanus symptoms usually begin about 5 to 10 days after the injury.
Muscle spasms are the characteristic feature of tetanus. Muscles contract involuntarily (spasm) and become rigid. Spasms usually begin in the jaw (causing lockjaw) and throat (making swallowing difficult), followed by the neck, shoulder, face, and then the abdomen and limbs. Such spasms may interfere with breathing, sometimes so much that people turn blue. The face may be frozen in a smile with the eyebrows raised. Back muscles contract, making the back arch. Spasms of sphincter muscles can lead to constipation and difficulty urinating. Slight disturbances—such as noise, a draft, or the bed being jarred—can trigger painful muscle spasms throughout the body. Rarely, muscle spasms may be limited to muscle groups near the wound. Such localized tetanus may persist for weeks.
Other symptoms occur because tetanus affects the nervous system, including the part that regulates internal body processes, such as how fast the heart beats. People may be restless and irritable. However, even when the illness is severe, people remain fully conscious. They may have a rapid heartbeat, profuse sweating, and a high fever.
Worldwide, about 50% of people who have tetanus die, usually because spasms of muscles in the throat, chest, and abdomen interfere with breathing. But in the United States, only about 6% die if the disorder is treated appropriately. People who inject drugs, the very young, and the very old are more likely to die of tetanus.
In newborns, tetanus usually affects the whole body and is frequently fatal. Children who survive may be deaf.
A doctor suspects tetanus when certain muscles (commonly, jaw and back muscles) become rigid or spasms occur, particularly in people who have a wound.
The bacteria can sometimes be grown (cultured) from a sample taken from the wound. However, culture results sometimes indicate tetanus when it is not present (a false-positive result), and tetanus may be present even if no bacteria are detected (a false-negative result). Thus, doctors do not rely on culture to diagnose tetanus.
Tetanus rarely develops in people who have completed a primary series of tetanus vaccinations (three or more injections into a muscle) and had vaccinations every 10 years, as recommended. The tetanus vaccine stimulates the body to produce antibodies that neutralize the toxin. But neutralization can take weeks.
In young children, the tetanus vaccine is given as part of a series that includes the diphtheria and pertussis (whooping cough) vaccines (see Table: Vaccinating Infants and Children).
Adults who have completed the primary series of tetanus vaccination should get tetanus boosters every 10 years.
When people are injured, they can help prevent tetanus by promptly and thoroughly cleaning wounds. People who have wounds may be given tetanus vaccine to prevent tetanus from developing. Because the vaccine takes weeks to be effective, tetanus immune globulin is sometimes given in addition. It provides antibodies that neutralize the toxin immediately.
After a Wound: Who Needs a Tetanus Shot?
People with tetanus are admitted to an intensive care unit. The room is kept quiet to prevent disturbances that could trigger muscle spasms. Wounds are cleaned thoroughly, and dead tissue and foreign material are removed.
Antibiotics (usually metronidazole) are given intravenously to kill the bacteria and thus stop the production of toxin. However, antibiotics have no effect on toxin that has already been produced. Such toxin continues to cause muscle spasms. Tetanus immune globulin is usually given to neutralize the toxin already produced. Tetanus vaccine is given unless vaccinations are known to be up to date.
Sedatives, such as the benzodiazepine diazepam, may be given to control muscle spasms, to help relax rigid muscles, and to relieve pain and anxiety.
If muscle rigidity interferes with breathing, a tube may be placed in the windpipe (called endotracheal intubation), and the person is given a drug to paralyze the muscles and thus prevent the spasms. Then the tube is attached to a Mechanical Ventilation.
If swallowing is difficult, nutrition and fluids are given intravenously or, less often, through a tube inserted through the nose and into the stomach.
After people recover, they are given the full series of vaccinations to prevent future episodes of tetanus.