Tetanus (or lockjaw) is a serious infection caused by Clostridium tetani bacteria which produce a toxin that affects the brain and nervous system. The toxin leads to stiffness in the jaw muscles as well as other muscles. The infection can cause severe muscle spasms, serious breathing difficulties, and can ultimately be fatal.
Clostridium tetani spores can be found most commonly in soil, dust and manure, but also exist virtually anywhere. If deposited in a wound the neurotoxin interferes with nerves that control muscle movement.
Although tetanus treatment exists, it is not uniformly effective. The best way to protect yourself from tetanus is to have the vaccine.
Symptoms of tetanus
Tetanus symptoms usually emerge about 10 days after initial infection, however this can vary from 4 days to about 3 weeks, and in some cases may take months. In general, the further the injury site is from the central nervous system, the longer the incubation period. Patients with shorter incubation periods tend to have more severe symptoms.
Muscle symptoms - there are muscle spasms and muscular rigidity (muscles become stiff). Stiffness usually starts with the chewing muscles, hence the name lockjaw. Muscle spasms then spread to the neck and throat, causing dysphagia (difficulty swallowing). Patients usually go on to have spasms in their facial muscles.
Breathing difficulties may result from neck and chest muscle stiffness. With some patients, abdominal and limb muscles are also affected.
In severe cases the spine will arch backwards as the back muscles are affected - this is more common when children are infected.
Most patients with tetanus will also have the following symptoms:
- Bloody stools (feces)
- Sensitivity to touch
- Sore throat
- Tachycardia (rapid heartbeat).
If the patient does not receive treatment the risk of life-threatening complications is higher - Mortality rates reported vary from 40% to 78% - symptoms may include:
- Asphyxia (suffocation)
- Heart attack
- Kidney failure
- Septicemia (blood poisoning).
Causes of tetanus
Tetanus is caused by the Clostridium tetani bacterium. Clostridium tetani spores are able to survive for a long time outside of the body. They are most commonly found in animal manure and contaminated soil, but may exist virtually anywhere.
When Clostridium tetani enter the body they multiply rapidly and release tetanospasmin, a neurotoxin (poison that affects the nervous system). When tetanospasmin enters the bloodstream it rapidly spreads around the body, causing tetanus symptoms.
Tetanospasmin interferes with the signals sent from the brain to the nerves in the spinal cord, and then on to the muscles, causing muscle spasms and stiffness.
Puncture wounds - Clostridium tetani enters the body mainly through a skin lesion (skin cut or puncture wound). Deeper cuts are ideal environments for infection because the bacteria thrive and multiply in places with very little or no oxygen. Thoroughly cleaning any cut helps prevent an infection from developing.
Tetanus infections may also develop as a result of:
- Animal bites
- Skin burns
- Abrasions and lacerations
- Injecting drugs with dirty needles
- Tattoos that are performed with unsterilized equipment
- Body piercing performed with dirty equipment
How is tetanus diagnosed?
In many countries an average GP (general practitioner, primary care physician) may not ever see a patient with tetanus. This is because the tetanus vaccine has been part of routine childhood immunization programs throughout most of the world and the infection has become rare. In the UK, for example, there were merely 60 cases between 2000 and 2007.
The earlier a patient is diagnosed with tetanus the more effective his/her treatment will be. Even though most GPs have never diagnosed tetanus, its symptoms are easily recognized. A patient with muscle spasms and stiffness who has recently had a wound or cut is usually diagnosed quickly.
Diagnosis may take longer with patients who inject drugs because they often have other medical conditions. They made need a blood test for confirmation.
Anybody who experiences muscle spasms and stiffness should seek medical attention immediately.
On the next page we look at the treatments for tetanus and how the condition can be prevented.