Health Encyclopedia

Tetanus

Definition

Tetanus is a potentially deadly nervous system disease due to the bacteria Clostridium tetani (C. tetani).

Alternative Names

Lockjaw

Causes, incidence, and risk factors

Spores of the bacteria C. tetani live in the soil and are found around the world. In the spore form, C. tetani may remain inactive in the soil, but it can remain infectious for more than 40 years.

Tetanus causes approximately five deaths per year in the United States. Internationally, it may reach up to 1 million cases a year. Tetanus infections in newborns make up about half of tetanus-related deaths in developing countries.

Infection begins when the spores enter the body through an injury or wound. The spores release active bacteria that spread and make a poison called tetanospasmin. Tetanospasmin blocks nerve signals from the spinal cord to the muscles, causing severe muscle spasm. Spasmodic contractions can be so powerful that they tear the muscles or cause compression fractures of the vertebrae.

Tetanus often begins with mild spasms in the jaw muscles (trismus), neck muscles, and facial muscles. Stiffness rapidly develops in the chest, back, abdominal muscles, and sometimes the laryngeal muscles (which then interferes with breathing). Muscular seizures (tetany) cause sudden, powerful, and painful contraction of muscle groups. These episodes can cause fractures and muscle tears.

The time between infection and the first sign of symptoms is 5 days to 15 weeks, with 7 days as the average. Most cases of tetanus in the United States occur in those who have not been properly vaccinated against the disease.

Symptoms

Spasms and tightening of the jaw muscle ("lockjaw")
Stiffness and spasms of various muscle groups
- Neck muscles
- Chest muscles
- Abdominal muscles
- Back muscles, often causing arching (opisthotonos)
Tetanic seizures (painful, powerful muscle contractions)
Irritability
Fever

Additional symptoms that may be associated with this disease:

Excessive sweating
Swallowing difficulty
Hand or foot spasms
Drooling
Uncontrolled urination or defecation

Signs and tests

Your doctor will perform a physical exam and ask questions about your medical history. No specific lab test is available to determine the diagnosis of tetanus.

Other tests may be used to rule out meningitis, rabies, strychnine poisoning, and other diseases with similar symptoms.

Treatment

Treatment may include:

Medicine to reverse the poison (tetanus immune globulin)
Antibiotics including penicillin, clindamycin, erythromycin, or metronidazole
Surgery to clean the wound and remove the source of the poison (debridement)
Muscle relaxers such as diazepam
Bedrest with a nonstimulating environment (dim light, reduced noise, and stable temperature)
Sedatives

Respiratory support with oxygen, endotracheal tube, and mechanical ventilation may be necessary.

Expectations (prognosis)

Without treatment, one out of three people die. The death rate for newborns with untreated tetanus is even higher. With proper treatment, less than 10% of infected patients die.

Wounds on the head or face seem to be more dangerous than those on other parts of the body. If the person survives the acute illness, recovery is generally complete. Uncorrected episodes of hypoxia (lack of oxygen) caused by muscle spasms in the throat may lead to irreversible brain damage.

Complications

Airway obstruction
Respiratory arrest
Heart failure
Pneumonia
Fractures
Brain damage due to lack of oxygen during spasms

Calling your health care provider

Call your health care provider if you have an open wound, particularly if:

You are injured outdoors
The wound has been in contact with soil
You have not received a tetanus booster (vaccine) within 5 years or you are not sure of your vaccination status

Call for an appointment with your health care provider if you have never been immunized against tetanus as an adult or child, if your children have not been immunized, or if you are unsure of your tetanus immunization (vaccine) status.

Prevention

Tetanus is completely preventable by active tetanus immunization. Immunization is thought to provide protection for 10 years. Studies in the army suggest that good protection persists up to 12 years after the last immunization.

In the U.S., immunizations begin in infancy with the DTaP series of shots. The DTaP vaccine is a "3-in-1" vaccine that protects against diphtheria, pertussis, and tetanus. It is a safer version of an older vaccine known as DTP, which is no longer used in the U.S.

Td vaccine or Tdap vaccine is used as a booster to maintain immunity in those age 11 to 65.

Older teenagers and adults who have sustained injuries, especially puncture-type wounds, should receive booster immunization for tetanus if more than 10 years have passed since the last booster.

Thorough cleaning of all injuries and wounds and the removal of dead or severely injured tissue (debridement), when appropriate, may reduce the risk of developing tetanus. If you have been injured outside or in any way that makes contact with soil likely, contact your health care provider regarding the possible risk for tetanus.

Many people believe injuries caused by rusty nails are the most dangerous. This is true only if the nail is dirty as well as rusty, as is usually the case. It is the dirt, not the rust, that carries the risk for tetanus.

Review Date:11/27/2006
Reviewed By:D. Scott Smith, M.D., MSc, DTM&H, Chief of Infectious Disease & Geographic Medicine, Kaiser Redwood City, CA & Adjunct Assistant Professor, Stanford University. Review provided by VeriMed Healthcare Network.

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