What Is Tetanus?
Tetanus is an infectious disease caused by wounds contaminated with the bacteria Clostridium tetani that live in soil and animal feces.
Tetanus is an infectious disease caused by contamination of wounds with the bacteria Clostridium tetani, and/or the spores they produce that live in the soil and animal feces.
Tetanus has been recognized for centuries. The term is derived from the ancient Greek words tetanos and teinein, meaning taut and stretched, which describe the condition of the muscles affected by the toxin produced by Clostridium tetani.
- The causative bacterium, Clostridium tetani, is a hardy organism capable of living many years in the soil in a form called a spore. The bacteria were first isolated in 1889 by S. Kitasato while he was working with R. Koch in Germany. Kitasato also found the toxin responsible for tetanus and developed the first protective vaccine against the disease.
- Tetanus usually occurs when a wound becomes contaminated with Clostridium tetani bacterial spores. Infection follows when spores become activated and develop into gram-positive bacteria that multiply and produce a very powerful toxin (tetanospasmin) that affects the muscles.
- Tetanus spores are found throughout the environment, usually in soil, dust, and animal waste. The usual locations for the bacteria to enter the body are puncture wounds, such as those caused by rusty nails, splinters, or even insect bites. Burns or any break in the skin and IV drug access sites are also potential entryways for the bacteria. Tetanus is acquired through contact with the environment; it is not transmitted from person to person.
- Tetanus results in severe, uncontrollable muscle spasms. For example, the jaw is "locked" by muscle spasms, causing the disease to sometimes be called "lockjaw." In severe cases, the muscles used to breathe can spasm, causing a lack of oxygen to the brain and other organs that may possibly lead to death.
- The disease in humans is the result of infection of a wound with the spores of the bacteria Clostridium tetani. These bacteria produce the toxin (poison) tetanospasmin, which is responsible for causing tetanus.
- Tetanospasmin binds to motor nerves that control muscles, enters the axons (filaments that extend from nerve cells), and travels in the axon until it reaches the body of the motor nerve in the spinal cord or brainstem (a process termed retrograde intraneuronal transport).
- Then the toxin migrates into the synapse (small space between nerve cells critical for transmission of signals among nerve cells) where it binds to nerve terminals and inhibits or stops the release of certain inhibitory neurotransmitters (glycine and gamma-aminobutyric acid).
- Because the motor nerve has no inhibitory signals from other nerves, the chemical signal to the motor nerve of the muscle intensifies, causing the muscle to tighten up in a huge continuous contraction or spasm. If tetanospasmin reaches the bloodstream or lymphatic vessels from the wound site, it can be deposited in many different locations and result in the same effect on other muscles.
In the United States, because of widespread immunization and careful wound care, the total annual number of cases has averaged about 40-50 cases per year since 1995.
In developing countries of Africa, Asia, and South America, tetanus is far more common. The annual worldwide incidence is between 500,000-1 million cases. The majority of new cases worldwide are in neonates in third-world countries.
The disease can show four possible types:
- Generalized tetanus can affect all skeletal muscles. It is the most common as well as the most severe form of the four types.
- Local tetanus manifests with muscle spasms at or near the wound that has been infected with the bacteria.
- Cephalic tetanus primarily affects one or several muscles in the face rapidly (in one to two days) after a head injury or ear infection. Trismus ("lockjaw") may occur. The disease can easily progress to generalized tetanus.
- Neonatal tetanus is similar to generalized tetanus except that it affects a baby that is less than 1 month old (called a neonate). This condition is rare in developed countries.
How Do You Get Tetanus?
Picture of tetanus (Clostridium tetani), with spore formation (oval forms at end of rods). Source: CDC/Dr. Holdeman
Clostridium tetani is a gram-positive rod-shaped bacterium that is found worldwide in soil.
It is usually in its dormant form, spores, and becomes the rod-shaped bacterium when it multiplies. The vegetative rods produce the spore usually at one end of the rod (Figure 1). The organisms are considered anaerobic, meaning they do not require oxygen to survive.
- Clostridium tetani is the bacterium responsible for the disease. The bacteria are found in two forms: as a spore (dormant) or as a vegetative cell (active) that can multiply.
- The spores are in soil, dust, and animal waste and can survive there for many years. These spores are resistant to extremes of temperature.
- Contamination of a wound with tetanus spores is rather common. Tetanus, however, can only occur when the spores germinate and become active bacterial cells that release exotoxins.
- The active bacterial cells release two exotoxins, tetanolysin and tetanospasmin. The function of tetanolysin is unclear, but tetanospasmin is responsible for the disease.
- Typically, a person gets tetanus after an acute injury or trauma that results in a break in the skin. Most cases result from a puncture wound, laceration (cut), or an abrasion (scrape).
- Other tetanus-prone injuries include the following:
- Crush wound
- IV drug users (site of needle injection)
- Wounds with devitalized (dead) tissue (for example, burns or crush injuries) or foreign bodies (debris in them) are most at risk of developing tetanus.
- Tetanus may develop in people who are not immunized against it or in people who have failed to maintain adequate immunity with active booster doses of vaccine.
Do I Need a Tetanus Shot?
- Not obtaining the tetanus vaccine or a tetanus vaccine booster vaccine puts individuals at higher risk for tetanus.
- Wounds, burns, frostbite, or skin breaks exposed to dirt, dust, or animal feces increases the risk of tetanus.
- Also, deep penetrating wounds (like those obtained from stepping on a rusty or dirty nail) are at high risk for tetanus development. Such a wound may be medically termed a "tetanus prone wound."
- People who survive injuries during natural disasters (tornadoes and hurricanes, for example) may have multiple tetanus-prone wounds; some may not be identified or known to the patient.
What Are the Symptoms and Signs of Tetanus?
Figure 2: Picture of opisthotonus or arched back due to muscle spasms in a person with generalized tetanus. Source: CDC
The hallmark feature of tetanus is muscle rigidity and spasms.
The median incubation period is seven days with a range from about four to 14 days.
The shorter the incubation period, usually the more severe are the symptoms.
In generalized tetanus, the initial complaints may include any of the following:
- Irritability, muscle cramps, sore muscles, weakness, or difficulty swallowing are commonly seen.
- Facial muscles are often affected first. Trismus or lockjaw is most common. This condition results from spasms of the jaw muscles that are responsible for chewing. A sardonic smile -- medically termed risus sardonicus -- is a characteristic feature that results from facial muscle spasms.
- Muscle spasms are progressive and may include a characteristic arching of the back known as opisthotonus (Figure 2). Muscle spasms may be intense enough to cause bones to break and joints to dislocate.
- Severe cases can involve spasms of the vocal cords or muscles involved in breathing. If this happens, death is likely, unless medical help (mechanical ventilation with a respirator) is readily available.
- In cephalic tetanus, in addition to lockjaw, weakness of at least one other facial muscle occurs. In two-thirds of these cases, generalized tetanus will develop.
- In localized tetanus, muscle spasms occur at or near the site of the injury. This condition can progress to generalized tetanus.
- Neonatal tetanus is identical to generalized tetanus except that it affects the newborn infant. Neonates may be irritable and have poor sucking ability or difficulty swallowing.
Should I Call a Doctor for Tetanus?
When to call the doctor
- Individuals should know if their tetanus immunization is current; often primary-care physicians have immunization records and may be able to supply people with that information.
- If people have a wound, they should seek medical attention. If they are not immunized against tetanus or have not kept up tetanus booster shots every 10 years, any open wound is at risk of developing tetanus. Many emergency physicians advise a tetanus booster be given if the patient's last booster is between 5 to 10 years old because patients may not accurately recall the date of their last booster and also because not all patients' immune systems will give 10-year protection following the vaccine.
When to go to the hospital
- Most doctors can care for minor wounds with mild degrees of contamination. In addition, most doctors maintain tetanus vaccines in their offices and can, if they have the records, vaccinate anyone who is inadequately immunized. Call the patient's doctor and follow his or her advice regarding whether or not they should seek treatment in a hospital's emergency department after an injury or wound.
- If the wound is large, contains crushed tissues, or is heavily contaminated, individuals should go to the nearest hospital's emergency department for evaluation. Occasionally, both a tetanus booster and tetanus antibodies are required if patients have any wound that is tetanus-prone. Tetanus antibodies are reserved for people with incomplete immunizations with a tetanus-prone wound.
- If individuals have a recent injury and are starting to experience muscle cramps or spasms at or near the injury, they should go to a hospital's emergency department immediately.
- If individuals have trouble swallowing or have muscle spasms in the facial muscles, go to the emergency department for treatment immediately.
How Is Tetanus Diagnosed?
The diagnosis of generalized tetanus is usually made by observing the clinical presentation and a combination of the following:
- History of a recent injury resulting in skin breakage (but this is not universal; only 70% of cases have an identified injury)
- Incomplete tetanus immunizations
- Progressive muscle spasms (starting in the facial region, especially lockjaw and progressing outward from the face to include all muscles of the body)
- Changes in blood pressure (especially high blood pressure)
- Irregular heartbeat
- In localized tetanus, pain, cramps, or muscle spasms occur at or near a recent skin injury.
- Neonates show signs of being generally irritable, muscle spasms, and poor ability to take in liquids (poor sucking response), usually seen in neonates about 7-10 days old.
- Laboratory tests are rarely used to diagnose tetanus. However, some reference labs can determine if the patient has serum antitoxin levels that are protective, and thus a positive test detecting these levels suggests that the diagnosis of tetanus is unlikely.
Are There Home Remedies for Tetanus?
- Any wound that results in a break in the skin should be cleaned with soap and running water.
- All open wounds are at risk to develop tetanus. Wounds from objects outdoors or crush injuries are at higher risk for getting C. tetani spores into a wound.
- Apply a clean and dry cloth to stop or minimize bleeding.
- Apply direct pressure to the site of bleeding to help minimize blood loss.
- Do not take chances; if the injured person is unsure of their tetanus vaccine status or if the injury may have "dirt" in it, they should visit the nearest emergency-care center.
What Is the Treatment for Tetanus?
Medical treatment has two aims: limit growth and eventually kill the infecting C. tetani and thus eliminate toxin production; the second aim is to neutralize any toxin that is formed. If the toxin has already affected the patient, the two aims are still important, but supportive measures will be needed for the patient. These steps are outlined below:
- Antibiotics (for example, metronidazole [Flagyl, Flagyl 375, Flagyl ER], penicillin G or doxycycline [Adoxa, Alodox, Avidoxy, Doryx, Monodox, Oracea, Oraxyl, Periostat, Vibramycin, Vibramycin Calcium, Vibramycin Monohydrate, Vibra-Tabs]) to kill the bacteria, tetanus booster shot, if necessary, and occasionally, antitoxin (termed tetanus immune globulin or TIG) to neutralize the toxin
- Wound cleansing to remove any obvious bacteria collections (abscesses) or foreign bodies; if the patient is exhibiting any toxin-related problems, TIG is usually administered first and wound care is delayed for a few hours while the TIG neutralizes toxin because infected wounds, when manipulated, may release more toxin
- Supportive measures
- Pain medicine as needed
- Sedatives such as diazepam (Valium) to control muscle spasms and muscle relaxants
- Ventilator support to help with breathing in the event of spasms of the vocal cords or the respiratory muscles
- IV rehydration because, as muscles spasm constantly, increased metabolic demands are placed on the body
How Long Does a Tetanus Shot Last?
The majority of all adult types of tetanus cases can be prevented by active immunization with tetanus toxoid (tetanospasmin toxin that is inactivated). Neonatal cases are prevented by good hygiene and careful, sterile technique used to sever the umbilical cord and later (at 2 months old), beginning active immunizations.
There are two main vaccines recommended by the U.S. Centers for Disease Control and Prevention (CDC):
- For pediatric populations, DTaP (diphtheria, tetanus, and acellular pertussis combination vaccine) is used.
- For nonimmunized adults and booster shots, Tdap (tetanus and reduced amounts of diphtheria and acellular pertussis combination vaccine) is recommended. Tdap was recommended (by the CDC) over the older Td combination vaccine, as cases of pertussis (whooping cough) had been increasing in the last decade.
DPT is infrequently used to describe this combination vaccine. DPT represents the combination vaccine but contains cellular pertussis antigen, not acellular pertussis antigen, and has not been used in the U.S. since 2002. The current designation is DTaP. In addition, DPT is an abbreviation used in the Netherlands for another type of combination vaccine: diphtheria, pertussis, and polio.
- All partially immunized as well as unimmunized adults should receive a tetanus vaccination (see below).
- The initial series for non-immunized adults involves three doses of Tdap:
- The first and second doses are given four to eight weeks apart.
- The third dose is given six months after the second.
- Booster doses are required every 10 years after that.
- In children, the immunization schedule calls for a shot frequency of five doses of DTaP.
- One dose is given at 2, 4, 6, and 15-18 months of age.
- This DTaP series is completed with a final dose when the child is between 4-6 years of age.
- Additional boosters with Tdap are given every 10 years after the final DTaP dose. Children who miss doses of DTaP can be given Tdap doses, but the choice for dose schedule should be determined by the patients' doctor.
- Pregnancy is not considered a contraindication for Tdap or Td vaccine according to the CDC.
People who are not completely immunized and have a tetanus-prone wound should receive a tetanus booster in addition to tetanus antibodies (human tetanus immune globulin or TIG). The tetanus antibodies (TIG) will provide short-term protection against the disease.
For patients sensitive to the combined vaccines (DTaP or Tdap), other vaccines against tetanus are available (for example, Td), but the patients' doctor should determine the dosage schedule.
- Vaccine side effects: Vaccine shots are somewhat painful (pain likely due to multiple factors such as inserting foreign material into a muscle, spreading out muscle fibers to make room for vaccine volume, the body's immune response, and others), but that pain should never prevent people from getting either immunized or obtaining booster shots. In most cases, the pain does not last long.
- Rarely, more serious side effects may occur (tetanus toxoid allergy). These individuals should not get tetanus booster shots but consult their doctor for advice for treatment. Patients with GI problems and/or GI bleeding may get worse symptoms as tetanus toxoid may lower platelet counts and decrease the person's ability to form blood clots. See other side effects section below.
What Is the Prognosis for Tetanus?
- Overall, about 25%-50% of people with generalized tetanus will die.
- The disease is more serious when the symptoms come on quickly.
- Older people and very young children tend to have more severe cases; those over 65 years are more likely to die from the infection.
- Intensive medical care improves the prognosis in severe cases.
- Death is usually due to respiratory failure or disturbance of heart rhythm.
- Data on worldwide neonatal deaths is not complete due to poor data collection in many countries; however, several investigators suggest mortality rates range from about 60%-80%.
- People who recover from tetanus have no long-lasting effects.
What Are the Tetanus Shot Side Effects?
- Problems with DTaP and Tdap range from mild to severe; the good news is that severe problems (seizures, coma, brain damage, nerve problems, or severe allergic reactions) occur in less than one in 1 million vaccinations.
- Many investigators think the severe complications are so rare that it is difficult to prove they are actually related to the vaccine administration. Consequently, the vast majority of physicians continue to advocate the use of the vaccines.
- The most frequent mild side effects of DTaP are pain, fever, fussiness in children, and redness or swelling at the injection site. About one in four children may show some or all of these effects, and they may be more prevalent after the fourth or fifth dose.
- Other mild problems (feeling tired, decreased appetite, vomiting, fussiness) may occur one to three days after the shot.
- Fussiness occurs most frequently (one in three children), followed by tiredness and decreased appetite (one in 10), while vomiting is infrequent (about one in 50).
- Moderate or uncommon effects of DTaP are a seizure or high fever (105 F or higher); these occur in about one of 14,000 children vaccinated.
- The most frequent mild side effects of Tdap are pain, redness, headache, chills, nausea with occasional vomiting or diarrhea, swollen lymph nodes, joint pain, and mild fever.
- Mild side effects occur in about two in three to three in four adolescents and adults while mild fever (100.4 F) may occur in one of 25 adolescents and one of 100 adults.
- Moderate side effects of Tdap are pain, redness, swelling, nausea, vomiting, diarrhea, and fever of 102 F or higher. Redness, swelling, and pain occur slightly more frequently in adolescents (about one in 16 to 20) than in adults (about one in 25 to 100). A similar frequency is seen with fever and gastrointestinal side effects (about one to three per 100 adolescents) compared with fever in one in 250 adults and gastrointestinal side effects in one in 100 adults.
- Most mild side effects of DTaP and Tdap usually require no treatment and are gone within 24 hours; moderate side effects may be treated symptomatically, but a child with a high fever or seizure should be evaluated and possibly treated by a physician. Do not use aspirin to treat children's pain or fever.
- Contraindications to vaccination are few; a toxoid allergy that previously manifested itself in the patient causing a serious allergic reaction (anaphylaxis, coma, or seizures) is the major contraindication for the vaccine.
- Other reasons may be due to illnesses that have occurred in some patients usually less than six weeks after previous vaccination (for example, Guillain-Barré syndrome).
- Consultation with an infectious-disease specialist physician may be helpful in the management of these infrequently seen patients.
- Finally, some people confuse DTaP and TB "shots." DTaP is a vaccine; in the U.S., a TB "shot" is slang verbiage for a skin test (termed a PPD test) that helps determine if a person has developed an immune response to bacteria that cause tuberculosis.
- The PPD test is not a vaccine or vaccination; it is an immunological skin test. Readers are advised to see the last citation in the information section below for a more complete discussion of the PPD test.