What Is Tetanus? What Causes Tetanus?
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.
What are the symptoms of 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 will also have the following symptoms:
- Bloody stools (feces)
- Sensitivity to touch
- Sore throat
- Tachycardia (rapid heartbeat)
- Asphyxia (suffocation)
- Heart attack
- Kidney failure
- Septicemia (blood poisoning)
What causes 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.
What is the treatment for tetanus?Cuts and wounds - any cut or wound must be thoroughly cleaned in order to prevent infection. A tetanus-prone wound should be treated by a medical professional immediately.
What is a tetanus prone wound? According to the National Health Service (NHS), UK, it is defined as:
- A wound that requires surgical intervention that is delayed for over six hours.
- A burn that requires surgical intervention that is delayed for more than six hours.
- A wound or burn that has a considerable amount of removed (devitalized) tissue.
- Any puncture-type injury that has been in contact with manure or soil.
- Serious fractures where the bone is exposed to infection (compound fractures).
- Wounds/burns in patients with systemic sepsis.
Antibiotics - doctors may prescribe penicillin and metronidazole for tetanus treatment. These antibiotics prevent the bacterium from multiplying and producing the neurotoxin that causes muscle spasms and stiffness. Patients who are allergic to penicillin or metronidazole may be given tetracycline instead.
Treatment for muscle spasms and stiffness
Patients may be prescribed:
- Anticonvulsants - these treat muscle spasms. Examples include diazepam (Valium) and phenobarbital (Barbita or Luminal).
- Diazepam - this drug relaxes the muscles, reduces anxiety and works as a sedative. It should be used for a short period only because long-term use can lead to dependency. Treatment should end gradually to reduce the likelihood or severity of withdrawal symptoms. Patients on diazepam should avoid driving or operating heavy machinery because of the side effects (below). Consuming alcohol will most likely worsen the side effects. Only under very special circumstances will diazepam be prescribed for pregnant women. Women should not breastfeed if they are taking diazepam.
Diazepam may have the following side effects:
- Reduced alertness
- Muscle weakness
- Muscle relaxants - these drugs help ease the symptoms of muscle stiffness and spasms. Examples include baclofen (Lioresal) and dantrolene (Dantrium).
- Baclofen - this medication suppresses the nerve signals from the brain to the spinal cord, resulting in less muscle tension. Although the medication does pass onto breast milk, it is not considered hazardous for the baby. Breastfeeding mothers should discuss this with their doctors.
Baclofen may have the following side-effects:
- Ataxia (wobbliness, incoordination and unsteadiness)
- Fits (seizures)
- Frequent urination
- Hallucinations (visual or auditory)
- Hypotension (drop in blood pressure)
- Vision problems
- Loss of appetite
- Skin rash
- Speech disturbances
- Tachycardia (raised heart beat)
- Vision problems
- Neuromuscular blocking agents - these medications block the signals from nerves to muscle fibers and are useful in controlling muscle spasms. An example is vacuronium, a neuromuscular blocking agent sometimes used as a muscle relaxant in addition to anesthesia during surgery.
- Surgery - If the doctor thinks the tetanus prone wound is very large, he/she may surgically remove as much of the damaged and infected muscle as possible (debridement). Debridement is the act of removing dead or contaminated tissue, or foreign material. In the case of a tetanus prone wound the foreign material may be dirt or manure.
- Nutrition - A patient with tetanus requires a high daily calorie intake because of increased muscle activity.
- Ventilator - Some patients may need ventilator support to help with breathing if their vocal cords or respiratory muscles are affected.
What are the possible complications of tetanus?
- Fractures - sometimes in severe cases the muscle spasms and convulsions may lead to fractures of the bones in the patient's back, as well as some other bones. Patients may develop myositis ossificans circumscripta (bone forms in soft tissues around joints).
- Aspiration pneumonia - if secretions or contents of the stomach are inhaled, which may sometimes happen in patients with tetanus, a lower respiratory tract infection can develop, leading to pneumonia.
- Laryngospasm - the larynx (voice box) goes into a spasm which can last up to a minute and cause breathing difficulties. In severe cases the patient can suffocate.
- Tetanic seizures - if infection spreads to the brain the patient can have epileptic-like fits (seizures).
- Pulmonary embolism - a blood vessel in the lung can become blocked and affect breathing and circulation. The patient will urgently need oxygen therapy and anti-clotting medication.
- Severe kidney failure (acute renal failure) - severe muscle spasms can result in the destruction of skeletal muscle which can cause myoblobin - a muscle protein - leaking into the urine. This can cause acute renal failure (severe kidney failure).
Prevention of tetanusMost cases of tetanus occur in people who have never been immunized (never had the vaccine), or who did not have a booster shot within the preceding decade.
The tetanus vaccine
The tetanus vaccine is routinely given to children as part of the DTaP (diphtheria and tetanus toxoids and acellular pertussis) shot. The DTaP vaccine consists of five shots, usually given in the arm or thigh of children when they are:
- 2 months old
- 4 months old
- 6 months old
- 15 to 18 months old
- 4 to 6 years old