TETANUS, also known as “lock jaw”, is an infection that is caused by the anaerobic bacteria Clostridium tetani.

This bacteria exists as spores all over the environment in soil, dust, on farm tools, equipment, or in the stool of animals and humans.

Whenever the skin is breached (for example: umbilical cord cut at birth in a mother with no or inadequate immunisation, doing body piercings, tattoos, injection of drugs, gunshot wounds, broken bones with exposure to the environment, burns, bites from animals, or ulcers all over the body) the bacteria enters the bloodstream. In some reported cases no wound or condition where the bacteria could enter was identified.

The Clostridium tetani bacteria produces three types of exotoxin: tetanospasmin, tetanolysin and nonconvulsive toxin.

Tetanospasmin, a neurotoxin, is largely responsible for the signs and symptoms of tetanus. It binds irreversibly with the nerve endings after entry into the body and spreads to the brain, spinal cord and muscles. It then impairs the nerves that control the muscles of the body by inhibiting the chemicals that stop muscles from contracting by nervous control.

TYPES OF TETANUS

There are four types of tetanus: Generalised (affecting all of the body); localised (affecting specific areas, usually next to the site of entry of the bacteria); cephalic (affecting the head, face and neck muscles); and neonatal (affecting newborns).

Approximately three to 21 days (average eight days) after being infected, a progressive illness occurs. Tetanus causes spasm and stiffness of the jaw (trismus, unable to open mouth) and neck muscles, problems swallowing, stiffness in the muscles of the abdomen, and painful body spasms such as the spine (opisthotonos) that occur due to stimuli such as loud noises, light or even touch. The patient may also have abnormal vital signs such as fever, rapid heart rate and elevated blood pressure with sweating.

RISK FACTORS

* Lack of immunisation or insufficient doses of boosters against tetanus (especially in the elderly)

* Deep wounds, puncture wounds

* Dirty wounds (contaminated with faeces, dirt or grass, for eg barn yard wounds

* Injured tissues and tissues infected with other bacteria

* Foreign body in wound, for eg nails or splinter

COMPLICATIONS

Complications of this disease results in:

* Difficulty breathing and then respiratory failure, which can lead to the heart stopping and death from lack of oxygen

* Broken bones of the spine from the intense spasm of the muscles (opisthotonos), joint dislocations: jaw and shoulder dislocations, broken long bones

* Mental defects and disability, especially in infants

* Abnormal heart rhythms and heart disease

* Lung infections

* Kidney failure due to excess muscle breakdown and dehydration

* Clots in the legs and lung

* Stomach perforation and peptic ulcer

TREATMENT

Once tetanus is suspected, the patient should report to the emergency department.

A quick assessment is made of the airway, breathing and circulation of the patient and each managed appropriately. If the patient is having difficulty maintaining a secure airway, then endotracheal intubation is necessary (a tube has to be put in the trachea through the mouth or nose for breathing by a ventilator), later a tracheostomy tube (a tube in the trachea through the overlying skin is necessary for prolonged ventilation).

Blood investigations are taken from the patient, including blood culture and culture of the appropriate wound (while removing dead and devitalised tissues).

The patient is then given sedatives (morphine), muscle relaxants, drugs to prevent erratic blood pressures, breathing and heart rate, and antibiotics (metronidazole). The mainstay of therapy is tetanus immunoglobulins (ready-made antitoxin, antibodies to bind to the toxins not yet bound) and a dose of the tetanus vaccine to start immunisation, both given at opposite and separate sites.

The patient will need admission to the intensive care unit.

The course is often tumultuous for the patient and can result in death. For the spasms to stop new nerve endings usually have to be generated. Recovery usually occurs after four weeks.

PREVENTION

Tetanus prevention occurs by being completely immunised. The tetanus toxoid is given with the pertussis vaccine (DTap) at least four times in children (2, 4, 6, 15-18) months (termed the primary series), and then every five to 10 years booster doses (Td) are given (4-6, 11-12 years) then every 10 years afterwards.

If a patient’s immunisation status is not up to date for tetanus (vaccine not received in the last 10 years), but the primary series was given in childhood and a wound has occurred then only the tetanus toxoid vaccine is necessary.

If a wound is received and there is no or inadequate vaccination received, both the tetanus immunoglobulin and the vaccine is needed if it is a tetanus-prone wound. Some types of tetanus-prone wounds are deep, dirty, contaminated wounds with faeces and foreign bodies, puncture wounds and those greater than six hours without care that need surgical intervention.

Dr Romayne Edwards is a consultant emergency physician at the University Hospital of the West Indies and an associate lecturer at the University of the West Indies.