Merck Manual

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Larry M. Bush

, MD, FACP, Charles E. Schmidt College of Medicine, Florida Atlantic University

Last full review/revision May 2021| Content last modified May 2021
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Tetanus results from a toxin produced by the anaerobic bacteria Clostridium tetani. The toxin makes muscles contract involuntarily and become rigid.

  • Tetanus usually develops after a wound or an injury that breaks the skin becomes contaminated.

  • Diagnosis is based on symptoms.

  • Vaccination and appropriate wound care can prevent tetanus.

  • Treatment includes giving tetanus immune globulin to neutralize the toxin and treating symptoms until they resolve.

Tetanus is rare in the United States but is common in areas of the world where immunization coverage is low. It can occur in people of all ages, even infants.

Clostridium tetani is present in soil and animal feces and can live there for years. Tetanus bacteria may enter the body through

  • Wounds contaminated with soil or feces (especially if the wound is not adequately cleaned)

  • Skin punctures by contaminated needles (such as those used to inject illegal drugs or to tattoo or do body piercing)

Sometimes the injury is so small that people do not even go to a doctor. Injuries that involve a foreign body (such as a splinter, dirt, or bullet fragments) and dead tissue (such as burns, frostbite, gangrene, or crush injuries) are more likely to cause tetanus.

Occasionally, tetanus results when the uterus is damaged during an induced abortion or childbirth. Soil contamination of the stump of the umbilical cord, which may occur in parts of the world with inadequate sanitation, can cause tetanus in newborns.

Tetanus bacteria produce spores. Spores are an inactive (dormant) form of bacteria. Spores enable bacteria to survive when environmental conditions are difficult. When conditions are favorable, spores grow into bacteria. Clostridium tetani bacteria produce tetanus toxins. These toxins travel throughout the body and prevent certain nerves from sending signals to other nerves. As a result, muscles contract involuntarily, causing stiffness and painful muscle spasms.

Vaccination during childhood plus booster doses every 10 years during adulthood can prevent tetanus. Thus, tetanus occurs mainly in people who have not been vaccinated or not kept their vaccinations up to date. In the United States, the risk of developing tetanus is high for the following:

  • People who inject drugs

  • People over 60 because immunity decreases over time

  • People who were never given the primary series of tetanus vaccines, which is part of routine childhood vaccination

Symptoms of Tetanus

Tetanus symptoms usually begin about 5 to 10 days after the injury but may begin up to about 50 days later.

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, neck, and legs arch backward. 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 with tetanus may have a rapid heartbeat and a fever. They may sweat profusely. Blood pressure may go up and down. People may inhale (aspirate) the contents of their mouth into their lungs, resulting in pneumonia Aspiration Pneumonia and Chemical Pneumonitis Aspiration pneumonia is lung infection caused by inhaling mouth secretions, stomach contents, or both. Chemical pneumonitis is lung irritation caused by inhalation of substances irritating or... read more .

People may be restless and irritable. However, even when the illness is severe, people usually remain fully conscious.

In newborns, tetanus usually affects the whole body and is frequently fatal. Children who survive may be deaf.

Did You Know...

  • Promptly and thoroughly cleaning dirty wounds can help prevent tetanus.

Prognosis for Tetanus

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. But if treatment is delayed and tetanus is severe, as many as 60% may die. People who inject drugs, the very young, and the very old are more likely to die of tetanus. The outlook is worse if symptoms develop quickly and progress rapidly or if treatment is delayed.

With treatment, most people recover.

Diagnosis of Tetanus

  • A doctor's evaluation

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.

Prevention of Tetanus

Preventing tetanus is far better than treating tetanus.


Tetanus rarely develops in people who have completed a primary series of tetanus vaccinations Diphtheria-Tetanus-Pertussis Vaccine The diphtheria, tetanus, and pertussis vaccine is a combination vaccine that protects against these three diseases: Diphtheria usually causes inflammation of the throat and mucous membranes... read more (three or more injections into a muscle) and had booster vaccinations every 10 years, as recommended. The tetanus vaccine stimulates the body to produce antibodies that neutralize the toxin. But it may take several weeks after vaccination for these antibodies to develop.

Adults who have completed the primary series of tetanus vaccination should get tetanus boosters every 10 years.

Pregnant women are given the tetanus, diphtheria, and acellular pertussis vaccine Diphtheria-Tetanus-Pertussis Vaccine The diphtheria, tetanus, and pertussis vaccine is a combination vaccine that protects against these three diseases: Diphtheria usually causes inflammation of the throat and mucous membranes... read more (Tdap) during each pregnancy (preferably at 27 to 36 weeks gestation). This strategy prevents women and newborns from getting tetanus. When pregnant women are vaccinated, antibodies to tetanus are transferred from the mother to the fetus during pregnancy, and the newborn has antibodies to tetanus at birth.

After a wound

When people are injured, they can help prevent tetanus by promptly and thoroughly cleaning wounds.

People who have wounds may be given one dose of tetanus vaccine to prevent tetanus from developing. If people have not been previously vaccinated, they are given a second dose 1 month after the first and a third dose 2 months after the first. Then booster doses are given every 10 years.

Because the vaccine takes weeks to be effective, tetanus immune globulin Passive immunization Immunization enables the body to better defend itself against diseases caused by certain bacteria or viruses. Immunity (the ability of the body to defend itself against diseases caused by certain... read more is sometimes given in addition. This immune globulin is obtained from human donors who have high levels of antibodies to the tetanus toxin. These antibodies neutralize the toxin immediately. (Antibodies Antibodies One of the body's lines of defense (immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more Antibodies are proteins produced by the immune system to help defend the body against a particular attacker, such as tetanus toxin.)


Treatment of Tetanus

  • Wound cleaning and removal of dead tissue and foreign material

  • Antibiotics

  • Tetanus immune globulin

  • Treatment of symptoms, sometimes including a mechanical ventilator

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. A single dose of tetanus immune globulin is usually injected into a muscle to neutralize the toxin already produced. If tetanus immune globulin is unavailable, doctors may give people nonspecific immune globulin, which contains many different antibodies Antibodies One of the body's lines of defense (immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more Antibodies , including those that defend against tetanus.

People do not develop immunity to tetanus once they have had tetanus. That is, they can get tetanus again. Therefore, after people who have tetanus recover from the infection, they are given tetanus vaccine unless their vaccinations are known to be up to date.

Management of symptoms

For muscle spasms and rigidity, sedatives, such as diazepam or midazolam, may be given. These drugs also help relieve 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 stop the spasms. Then the tube is attached to a mechanical ventilator Mechanical Ventilation Mechanical ventilation is use of a machine to aid the movement of air into and out of the lungs. Some people with respiratory failure need a mechanical ventilator (a machine that helps air get... read more .

If swallowing is difficult, nutrition and fluids are given intravenously or, less often, through a tube inserted through the nose and into the stomach.

If constipation, which is common, develops, stool softeners are given, and a tube may be inserted into the rectum to help manage gas production.

More Information

The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

Drugs Mentioned In This Article

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Gammagard S/D
No US brand name
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