A disease caused by the toxin of the bacterium Clostridium tetani that affects the central nervous system , sometimes resulting in death.
Causes, incidence, and risk factors
Spores of the bacterium Clostridium tetani live in the soil and are distributed worldwide. In the spore form, Clostridium tetani may remain dormant in the soil, but can be infectious for periods longer than 40 years. Infection begins when the spores are introduced into an injury or wound . The spores germinate, releasing active bacteria that multiply and produce a neurotoxin, called tetanospasmin. Tetanospasmin selectively blocks inhibitory nerve transmission from the spinal cord to the muscles, allowing the muscles to go into severe spasm. Spasmodic contractions may 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. During these episodes, fractures and muscle tears can occur. Without treatment, 1 out of 3 affected people die. The mortality rate for newborns with untreated tetanus is even higher, 2 out of 3. With proper treatment, less than ten percent of the patients die. The incubation period is 5 days to 15 weeks, with 7 days as the average. About 100 cases of tetanus occur every year in the U.S., the vast majority in un-immunized individuals or those whose last immunization was no longer current. In developing countries, tetanus frequently causes death in newborn infants when the umbilical stump becomes infected.
Signs and tests
Diagnosis of tetanus is based on the history and physical findings that are characteristic of the disease. Diagnostic studies generally are of little value. Cultures of the wound site are negative for Clostridium tetani two-thirds of the time. When the culture is positive, it is diagnostic. Tests that may sometimes be performed include:
Culture of the wound site Tetanus antibody test
Other tests to rule-out meningitis , rabies , strychnine poisoning or other diseases with similar symptoms
Treatment
Control and reverse the tetany with antitoxin, tetanus immune globulin. Penicillin can be given to kill the Clostridium tetani ; other antibiotics such as clindamycin, erythromycin, or metronidazole can be used in patients who are allergic to penicillin.
Remove and destroy the source of the toxin through surgical exploration and cleaning of the wound (debridement). Treat symptoms with supportive therapy. Muscle spasms can be treated with muscle relaxants such as diazepam. Bedrest with a non-stimulating environment is also recommended (dim light, reduced noise, and stable temperature). Sedation may be necessary to keep the affected person quiet. Respiratory support with oxygen, endotracheal tube, and mechanical ventilation may be necessary.
Expectations (prognosis)
The death rate is high in children and in the elderly. Wounds on the head or face seem to be more dangerous than those on 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 larynx throat may lead to irreversible brain damage.
Calling your health care provider
Call your health care provider if you sustain an open wound and you have not received a tetanus booster (vaccine) within 5 years. 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 are not immunized, or if you are unsure of your tetanus immunization (vaccine) status.
Prevention
Tetanus is completely preventable by active tetanus immunization (vaccine) . Tetanus immunizations are begun in infancy as a series of DPT shots (D = diphtheria , P = pertussis or whooping cough , and T = tetanus). Boosters are given to teenagers and older adults as Td shots (adult tetanus and diphtheria) or singly as just tetanus. Immunization is considered to provide protection for ten years. Studies in the army suggest that good protection persists up to 12 years after the last immunization. Older teenagers and adults who have been injured, especially puncture type injuries, should receive booster immunizations for tetanus if their last immunization was more than 10 years previously. 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.