Tetanus, also called lockjaw, is a serious disease of the nervous system that can cause uncontrolled muscle spasms and death. It is caused by toxins (poisons) produced by the bacterium Clostridium tetani.
Tetanus occurs when the body is infected with spores of the bacterium C. tetani. This bacterium is found worldwide in soil and animal manure. The spores can remain alive in the soil for years and are resistant to heating and chemical destruction. They are more common in hot, damp environments than in cold or dry ones.
Once spores enter the body through a break in the skin, they begin producing bacteria. These bacteria multiply in areas where there is little oxygen present and produce a toxin that affects the nervous system. The toxin spreads along the nerves of the body, causing the nerves to fire (react). This results in muscle spasms and convulsions.
The bacteria that cause tetanus enter the body through a scrape, cut, or wound, in about 70 percent of cases. The most susceptible wounds are those that are caused by blunt trauma such as crushing or by bites . The bacteria can also enter at the site of a burn, bedsore, or frostbite , or be introduced into the body during surgery. In developing countries, newborns often contract tetanus from contaminated instruments used to tie off the umbilical cord after birth. Often the site where the bacteria enter is insignificant, does not become swollen or red, and does not require medical attention. Any time between two and 50 days later (most commonly between days seven and 21 days), the individual begins to show the signs of tetanus.
The severity of the disease is related to several factors:
- The sooner symptoms appear, the more severe the disease.
- If the point of entry was in the head or face, symptoms are more severe.
- The very young and the very old suffer more severe symptoms and higher death rates.
With almost universal vaccination starting in the 1940s, tetanus has become rare in the United States. Fewer than 50 cases have been reported annually since 1995. Worldwide, the disease is common, especially in newborns in developing parts of Asia, Africa, and South America where immunization is not universally available. The disease can affect individuals of any race, age, or gender.
Causes and symptoms
Since the incubation period can range from several days to many weeks, individuals often do not associate their initial symptoms with wound infection. The first sign of tetanus is a tightening of the jaw muscles that gives the disease its common name, lockjaw. This symptom is followed by waves of back spasms. The spasms then extend to the arms producing clenched fists and to the legs. Any stimulus, such as noise or light, can set off a round of convulsions. Other symptoms include drooling, increase in blood pressure ( hypertension ), irregular heart beat, inability to open the mouth, high fever , kidney failure, and respiratory failure.
When to call the doctor
Tetanus is a medical emergency, and individuals should be taken to the emergency room as soon as symptoms are noticed. About 75 percent of individuals with tetanus are first seen by a dentist or oral surgeon for pain and stiffness in the jaw and mouth region.
Diagnosis of tetanus is based on presenting symptoms rather than laboratory tests. Less than one-third of the time can the bacteria that causes the disease be cultured from a wound.
Treatment begins immediately in the emergency room or intensive care unit of a hospital. There are five aspects of treatment. Initially the patient is placed in a dark, quiet room and given a sedative, usually a drug in the benzodiazepine family, through direct injection into a vein (IV) in an effort to reduce muscle spasms. A tube may be inserted in to the trachea (tracheotomy) in order to keep the airways open.
The second aspect of treatment is to clean and disinfect any wounds and remove any dead flesh.
The third aspect of treatment involves killing the bacteria producing the toxin using antimicrobial drugs given as an injection. The drug of choice is metronidazole (Flagyl), with penicillin the second choice.
Fourth, the toxin already circulating in the blood must be neutralized so that it causes no further damage to the nervous system. This is done with injections of human tetanus immunoglobulin (TIG).
Finally, complications of the disease are managed. This may involve IV fluid replacement, use of a respirator, or kidney dialysis. Contracting tetanus does not provide immunity against future infections, so tetanus immunizations are also given.
Individuals who develop symptoms within a few days of infection have close to a 100 percent mortality rate. The mortality rate for infections originating in the head and in newborns is also very high. The sooner an individual is treated, the more likely he or she is to survive. Overall, the death rate in the United States is 10 percent. Worldwide it is 45 percent. According the United States Centers for Disease Control, the average hospital stay is 16 days. Recovery for those who survive is normally complete after about four weeks.
Tetanus is completely preventable by immunization. The recommendation in the United States, as of 2004, is to immunize children against tetanus on the following schedule:
- initial vaccination at two months of age
- repeat at four months of age
- repeat at six months of age
- repeat at 12 to 15 months of age
- repeat at four to six years of age
- booster dose given every 10 years there after, normally at ages 15, 25, 35, etc.
Receiving the complete schedule of multiple vaccinations is necessary to ensure full protection. For children, vaccination against tetanus is normally included in a vaccine called DTaP that protects against diphtheria , tetanus, and whooping cough (acellular pertussis). Many school districts require proof of vaccination before a child may enroll.
Other prevention measures involve prompt cleaning and protection of wounds and hygiene measure such as washing well after exposure to soil containing animal manure. Sterile conditions during surgery also help prevent infection.
Food is not given by mouth to individuals who are having muscle spasms for fear they will breathe the food into their lungs. During this time, they are fed intravenously.
Some parents hesitate to vaccinate their children for religious reasons or because they fear side effects of the vaccination. The bacteria that cause tetanus are so common and the disease is so serious that protection against acquiring tetanus outweighs any risks associated with vaccination.
Intravenous —Into a vein; a needle is inserted into a vein in the back of the hand, inside the elbow, or some other location on the body. Fluids, nutrients, and drugs can be injected. Commonly called IV.
Toxin —A poisonous substance usually produced by a microorganism or plant.
Trachea —The windpipe. A tube composed of cartilage and membrane that extends from below the voice box into the chest where it splits into two branches, the bronchi, that lead to each lung.
Tracheotomy —An surgical procedure in which the surgeon cuts directly through the patient's neck into the windpipe below a blockage in order to keep the airway open.
Umbilical cord —The blood vessels that allow the developing baby to receive nutrition and oxygen from its mother; the blood vessels also eliminate the baby's waste products. One end of the umbilical cord is attached to the placenta and the other end is attached to the baby's belly button (umbilicus).
See also Vaccination .
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Tish Davidson, A.M.