Alternative names tetanus
What is lockjaw (tetanus)?Lockjaw (tetanus) is a disease caused by a toxin produced by the bacterium Clostridium tetani. The toxin affects the central nervous system, sometimes resulting in death.
What causes tetanus?Spores of the bacterium Clostridium tetani are found in soil and dust. Tetanus occurs when these spores enter the body through a break in the skin, particularly in the case of puncture wounds caused by nails, splinters, insect bites or gunshots. Bites and scratches from animals such as dogs and cats can also result in tetanus. Once in the body, the spores germinate, releasing active bacteria that multiply and produce neurotoxin. The bacteria stay at the site of inoculation, but the toxin can spread through the body. This toxin causes uncontrollable contraction of muscles, resulting in severe muscle spasms.
Who gets tetanus and who is at risk?People who have not been immunised against tetanus, or those whose last immunisation is no longer current, are at risk of getting tetanus if they’ve suffered an open wound.
In recent years, two thirds of all tetanus cases have been in persons 50 years of age and older.
Having had a tetanus infection in the past does not make you immune to tetanus in the future. Without treatment, one out of three affected people will die. The mortality rate for newborns with untreated tetanus is even higher - two out of three.
Symptoms and signs of tetanusCommon symptoms of tetanus include:
- Stiffness of the jaw - usually the first sign of tetanus
- Stiffness of the neck and other muscles
- Spasms of the neck and other muscles
- Rigidity of the chest muscles
- Rigidity of the abdominal muscles
- Spasms and rigidity of the back muscles, often causing arching of the back
- Seizures – painful, powerful bursts of muscle contraction
Other symptoms may include:
- Excessive sweating
- Difficulty swallowing
- Hand or foot spasms
- Uncontrolled urination
- Uncontrolled defecation
Tetanus can develop even after a wound which appears trivial and uninfected.
The incubation period is five days to 15 weeks.
How is tetanus diagnosed?Diagnosis of tetanus is based on the relevant medical history (Has there been a break in the skin? When was the last tetanus shot received?) and physical findings (common symptoms of tetanus).
Diagnostic tests, such as testing cultures of the wound site, are generally of little value. Two thirds of the time, wounds test negative for the Clostridium bacterium. Other tests that may be performed are tests to rule out meningitis, rabies, strychnine poisoning or other diseases with similar symptoms.
Can tetanus be prevented?The most important weapon against tetanus is adequate immunisation. Most people receive their first vaccine as children in the form of a combined tetanus-diptheria-pertussis (whooping cough) vaccine known as DTP. Booster shots are given to teenagers and adults as a Td booster or singly as tetanus only. Immunisation is considered to provide protection for 10 years.
Older teenagers and adults who have been injured, especially with puncture-type injuries, should receive booster immunisations for tetanus if their last immunisation was more than 10 years previously. However, some medical experts suggest that a vaccine is necessary if you haven’t had a booster in the last 5-10 years.
Thorough cleaning of all injuries and wounds and the removal of dead or severely injured tissue when appropriate, may reduce the risk of developing tetanus.
Make an appointment with your doctor if you have never been immunised against tetanus, or if you are unsure of your tetanus immunisation status.
How is tetanus treated?The first step in treatment is to control and reverse the tetanus with antitoxin. Because of the possible danger of hypersensitivity to horse serum antitoxin, tetanus immune globulin, which is derived from human serum instead, is preferred when available. This prevents hypersensitivity reactions to the toxin.
The second step is to remove and destroy the source of the toxin. The wound area must be carefully cleaned, and all dead tissue and foreign substances removed. Surgical removal of infected tissue may also be necessary. Penicillin is given intravenously to kill the toxin-producing Clostridium tetani.
Symptoms of tetanus can be treated with supportive therapy. Muscle spasms can be treated with muscle relaxants such as diazepam. Bed rest in a non-stimulating environment (dim light, reduced noise, and stable temperature) is also recommended.
During a tetanus attack, sedatives are given to reduce the frequency of convulsions. Padded side rails are also applied to the bed to prevent injury during a seizure.
Antibiotics may be used to help combat secondary infection with other bacteria. Fluids and nourishment are usually given intravenously during the acute stage of the disease. Respiratory support with oxygen, endotracheal tube (a tube inserted into the wind-pipe) and mechanical ventilation may also be necessary.
What is the outcome of tetanus?The death rate is high in children and 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.
When to call the doctor
Call your doctor if you sustain an open wound and you have not received a tetanus booster within five years.
(Reviewed by Dr Andrew Whitelaw, University of Cape Town and Groote Schuur Hospital)