Tetanus

Definition

Tetanus is a rare but often fatal disease that affects the central nervous system by causing painful and often violent muscular contractions. The earliest descriptions of the disease can be found in the medical papyri of ancient Egypt. The disease begins when the tetanus bacterium (Clostridium tetani) enters the body, usually through a wound or cut that has come in contact with the spores of the bacterium. Tetanus spores are commonly found in soil, dust, and animal manure. Tetanus is a noncommunicable disease, meaning that it cannot be passed directly from one person to another.

Description

Tetanus is uncommon in the United States, with nearly all cases occurring in adults who were not vaccinated as children, or in those who have not had a booster vaccination in 10 years.

In the United States, there are between 50 and 100 reported cases of tetanus a year. About 30% of cases are fatal. Most people who die of tetanus infections are over 50 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 that cannot be opened. Sometimes tetanus is localized, that is; it affects only the part of the body where the infection began. However, in almost all reported cases, tetanus spreads to the entire body. The incubation period from the time of the injury until the first symptoms appear ranges from five days to three weeks. Symptoms usually occur within eight to 12 days. The chance of death is increased when symptoms occur early.

Causes & symptoms

Tetanus is caused by a bacterium called Clostridium tetani, whose spores (the dormant form) are found in soil, street dust, and animal feces. The bacteria enter the body through cuts and abrasions but will multiply only in an environment that is anaerobic, or oxygen-free. Deep puncture wounds and wounds with a lot of dead tissue provide an oxygen-free environment for the bacteria to grow.

As C. tetani grows, it excretes a highly poisonous toxin called tetanospasmin into the bloodstream, spreading it throughout the nervous system. The infection is usually transmitted through deep puncture wounds or through 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; punctures caused by glass, thorns, needles, and splinters; and therapeutic abortion. Rare cases have been reported in people with no known wound or medical condition.

Neonatal tetanus in newborns can be caused by cutting the umbilical cord with an unsterile instrument or by improper care of the umbilical stump. Neonatal tetanus is less common in developed countries.

Tetanus toxin affects the nerve endings, causing a continuous stimulation of the muscles. Initial symptoms may include restlessness, irritability, a stiff neck, and difficulty swallowing. In about half of all cases, the first symptom is a stiff or "locked" jaw, which prevents patients from opening their mouths or swallowing. This symptom is also called trismus and results in a facial expression called risus sardonicus, which is a Latin phrase meaning "sardonic smile." Trismus is often followed by stiffness of the neck and other muscles throughout the body as well as uncontrollable spasms. Sometimes these convulsions, known as opisthotonos, are severe enough to cause broken bones. Other symptoms of tetanus include loss of appetite and drooling. People with localized tetanus 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. In many cases the risk is increased by the mother's giving birth on a floor made of hardpacked soil. Worldwide, 800,000 children die of tetanus each year.

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Author Info: Lisa Frick, Rebecca J. Frey PhD, The Gale Group Inc., Gale, Detroit, Gale Encyclopedia of Alternative Medicine, 2005

This feature is for informational purposes only and should not be used to replace the care and information received from your healthcare provider. Please consult a healthcare professional with any health concerns you may have.