Tetanus – Causes, Signs and symptoms

Tetanus

Also called: Clostridium Tetani Infection, Tetanus Disease, Lockjaw

Reviewed By:
David Slotnick, M.D

Summary

Tetanus is a disease that results from infection by Clostridium tetani bacteria. These bacteria produce the toxin tetanospasmin, which interferes with the ability of the nervous system to communicate with muscles. This often results in uncontrollable muscle contractions, or spasms, that can cause pain, fracture bones and inhibit breathing. Tetanus can be deadly if not treated quickly.

The tetanus bacteria can only survive in limited environments. They require an absence of oxygen and are highly sensitive to heat. To survive outside these conditions, they release dormant spores that are resistant to heat and can exist in soil and animal feces for decades. Infection results when the spores enter the body through an injury or open wound. They may become active, begin to multiply and produce toxin that is circulated throughout the body via the blood.

Tetanus is often diagnosed based on the occurrence of certain symptoms in conjunction with a recent injury. The disease is often first marked by jaw spasms and difficulty opening the mouth (lockjaw or trismus). Later indicators include difficulty swallowing and breathing, muscle stiffness or pain, muscle spasms elsewhere in the body and rigid abdominal muscles.

Patients diagnosed with tetanus typically require hospitalization for treatment. This begins with steps to prevent further toxin production through wound management. Antibiotics are used to kill the responsible bacteria. The tetanus toxins may or may not affect nerve endings. Medication is used to inactivate toxin particles that have not attached to nerve endings. Toxin that is attached to nerve endings will continue to cause spasms until the nerve endings regenerate, which can take four to six weeks. Meanwhile, patients may require sedatives and mechanical ventilation. Developing tetanus does not make a person immune to it in the future. Patients will need to be immunized to prevent further occurrences of the disease. Infection with tetanus is preventable through proper immunization. A series of shots over one to two years provides initial protection. Following that, a booster shot every 10 years maintains the immunization.

About tetanus

Tetanus is a serious and sometimes fatal disease caused by Clostridium tetani bacteria. These bacteria can only live under anaerobic (lacking oxygen) conditions and are also sensitive to heat. This can limit their presence in the environment, but they also produce spores that are resistant to heat and many common antiseptics. These spores may be found in soil, animal intestines and feces, and may remain infectious for more than 40 years.

Tetanus spores often enter the human body through an injury or wound. After they are inside the body, if the necessary conditions are present, they become active bacteria and begin to multiply. They also produce the toxin tetanospasmin, which is transported through the body in the circulatory and lymphatic systems. This toxin is one of the strongest known. Less than 3 nanograms (billionth of a gram) of tetanospasmin per kilogram of body weight is enough to kill a person.

When the toxin reaches the central nervous system, it attaches to nerve endings. This blocks the signals that control muscle movement. Instead of the normal action of contracting and then resting, muscles may remain contracted. The resulting spasms cause pain, limit breathing ability, and may be strong enough to break bones or tear muscle. To restore normal function, the nerves must grow new endings, a process that takes four to six weeks.

Without proper treatment, tetanus may lead to death. This is most likely in children and patients over 60 years old. The global occurrence of tetanus varies widely. According to data collected by the World Health Organization (WHO), up to 1 million cases are estimated to occur each year, resulting in approximately 300,000 deaths. The majority of these cases are in developing countries. In the United States and other industrial nations, the disease occurs infrequently. According to the Centers for Disease Control and Prevention (CDC), fewer than 100 cases of tetanus occur each year in the United States with a mortality rate of approximately 10 percent.

Types and differences of tetanus

Tetanus is characterized by muscle spasms. The disease may be classified by the distribution of spasms within the body. These types include:

  • Generalized tetanus. The most common and severe form of the disease. It is found in about 80 percent of cases. Muscle spasms frequently begin in the jaw, neck and face. They may then spread to the chest, back and abdomen. In some cases, muscles in the throat can spasm, interfering with the ability to swallow and breath. Reflex spasms are common and may be triggered by bright lights, loud noises or physical touch. During these spasms, patients will often clench their fists, arch their back, flex their arms and extend their legs.
  • Neonatal tetanus. A type of generalized tetanus that occurs in newborn infants. It usually occurs due to infection of the umbilical stump. This type of infection may occur when the mother has either not been immunized against tetanus or is not current on her shots. It rarely occurs in the United States.
  • Local tetanus. Anuncommon type of tetanus. It causes muscle spasms at or near the site of injury. Without treatment, it often develops into generalized tetanus. About 1 percent of cases of local tetanus are fatal.
  • Cephalic tetanus. Arare type of tetanus is often associated with head or neck injuries or ear infections. It affects the cranial motor nerves and frequently affects facial expressions. Cephalic tetanus may also progress into the generalized disease.

Risk factors and causes of tetanus

All cases of tetanus are caused by the bacteria Clostridium tetani and are characterized by muscle spasms. In general, tetanus may infect anyone. People most at risk include those who have not been immunized against tetanus or have not received their booster shots. In addition, users of injected drugs (e.g., heroin) have also been found to have a high incidence of the disease. Tetanus infection may also be associated with diabetes, though the reasons are unclear.

Tetanus is found globally but the spores are most dense in tropical areas. These regions have climates and soil that promote bacterial growth.

Although tetanus is an infectious disease, it is not contagious and cannot be transmitted from person to person. Instead, the spores enter the human body through breaks in the skin. The disease is frequently associated with puncture wounds, especially those involving rusty nails. However, the dirt often found on rusty nails is usually responsible for bacteria or spore transmission, not the rust. A wide range of injuries may allow spores to enter the body, such as:

  • Puncture wounds
  • Lacerations (cuts)
  • Abrasions
  • Burns
  • Crush wounds
  • Animal bites
  • Compound fractures (when the bone breaks the skin)
  • Middle ear infections
  • Dental infections

Tetanus infection may also occur following procedures that may involve making cuts into the skin, such as surgery, Caesarean delivery or an episiotomy procedure during childbirth.

Signs and symptoms of tetanus

Tetanus bacteria may live within the body for some time before signs or symptoms of infection begin to appear. This incubation period tends to be longer when the injury site is farther from the brain and spinal cord. It typically takes between three and 21 days, with an average of eight days, for symptoms of infection to appear. In some cases, months may pass before symptoms begin. Longer incubation periods are often associated with greater chance of a positive outcome.

The signs and symptoms of tetanus vary based on which type the patient develops. Generalized and neonatal tetanus typically cause the following:

  • Spasm of jaw muscles and difficulty opening the mouth (lockjaw or trismus)
  • Irritability
  • Restlessness
  • Sweating
  • Rapid heart rate
  • Difficulty swallowing (dysphagia)
  • Stiffness or pain in the neck, chest and back
  • Rigidity of abdominal muscles
  • Elevated blood pressure
  • Hand or foot spasms
  • Drooling
  • Inability to control urination and/or defecation

These signs and symptoms may also occur later in the progression of local and cephalic tetanus. In its early stages, muscle spasms associated with local tetanus are limited to the limb or body area where the injury occurred. Similarly, the cephalic form is often marked by muscle spasms only in the face prior to the development of generalized tetanus.

Diagnosis and treatment of tetanus

Most often, diagnosis of tetanus is made based on the patient’s medical history and the results of a physical examination. The medical history will likely include questions on symptoms, including their duration, severity and progression. Patients should also tell their physician about any recent injuries that may have penetrated the skin. A physical examination is performed to look for signs of tetanus. Laboratory cultures of infected wounds are often negative for tetanus and are usually not helpful in the diagnosis.

When tetanus is diagnosed, hospitalization is usually required for treatment. Patients may be placed in rooms where light and noise can be controlled to reduce the occurrence of muscle spasms.

Treatment begins with preventing bacteria from producing additional tetanospasmin toxin. This is done by cleaning the wound of embedded debris and dead tissue. In addition, antibiotics are used to kill bacteria living in the body. Short-term immunization (tetanus immune globulin) is also injected to remove toxin that is not attached to nerve endings. Toxin particles that are attached will continue to cause muscle spasms for four to six weeks, the time it takes for the nerve endings to regenerate. Because infection with tetanus does not provide immunity to the disease, patients will also likely be vaccinated to prevent further occurrences.

Over the next few weeks, treatment focuses on supportive care to control the muscle spasms and their effects. Sedatives may be administered to reduce the often painful muscle contractions. Because spasms often interfere with breathing, patients are likely to require a mechanical ventilator.

Complications may also occur during the treatment of tetanus. Spasms and convulsions may be strong enough to fracture vertebrae and bones in the arms and legs. The long treatment and recovery period in a hospital may lead to other diseases (e.g., pneumonia).

Tetanus is a nationally notifiable disease for the U.S. Centers for Disease Control and Prevention. This means that cases and supplementary information (e.g., clinical history, vaccination status, wound care) are reported by state and local health departments. If necessary, the patient may be contacted to provide further information.

Prevention methods for tetanus

Most cases of tetanus can be prevented with proper immunization. Tetanus vaccines are generally combined with vaccinations for diphtheria and whooping cough (pertussis). DTaP (diphtheria and tetanus toxoids and acellular pertussis vaccine) is recommended for children younger than seven years of age. It is usually given in a series of doses at 2, 4, 6 and 15 to 18 months. To maintain immunity, two booster doses of the vaccine are recommended when the child is between 4 and 6 years old and between 11 and 12 years old.

For those older than 7 who have not been immunized, three doses of a tetanus vaccine are recommended. The first is often Tdap (tetanus and diphtheria toxoids and acellular pertussis) followed at least four weeks later by a dose of Td (tetanus and diphtheria toxoids). A final dose of Td is administered within six to 12 months. 

Following initial immunization, all adults should receive Td booster shots every 10 years. In case of injury, Td boosters and possibly a dose of tetanus immune

globulin (short-term immunization) may be recommended. This is most likely if a booster has not been received within the last five years or the patient is unsure of his or her immunization status. Adult vaccinations that also provide protection from whooping cough may also be available

Pregnant women who have been vaccinated against tetanus may pass limited immunity to the fetus, which helps prevent neonatal tetanus. Vaccination is generally safe for pregnant women and is recommended for those who have not been vaccinated or received a booster within the past 10 years.

Adverse reactions to the vaccine are usually limited to the injection site. Common effects include local pain, reddening of the skin, or hardening of skin at the injection site. Painful swelling around the injection site may also appear within eight hours. Severe reactions are infrequent. Those that have been reported include hives, anaphylaxis (difficulty breathing, drop in blood pressure, loss of consciousness), dizziness, seizure and nausea. Minor injuries should be cared for promptly to reduce the chance of tetanus infection. This involves cleaning the area with water and soap, applying antibiotic creams or ointments, and keeping the wound covered with a sterile dressing. A physician should be seen for any serious injury.

Questions for your doctor regarding tetanus

Preparing questions in advance can help patients have more meaningful discussions with healthcare providers regarding their conditions. Patients may wish to ask their doctor the following questions related to tetanus:

  1. How can I prevent tetanus?
  2. What is the tetanus vaccination schedule?
  3. What are the possible side effects of tetanus vaccination?
  4. What kind of injuries can result in a tetanus infection?
  5. What are the early signs of tetanus?
  6. How is tetanus treated?
  7. Will treatment require hospitalization? If so, how long?
  8. What is my prognosis?
  9. Will being infected with tetanus once prevent its reoccurrence?
  10. Are there lasting effects of tetanus?
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