Tetanus (lockjaw)

• What is Tetanus (Lockjaw)
• Statistics on Tetanus (Lockjaw)
• Risk Factors for Tetanus (Lockjaw)
• Progression of Tetanus (Lockjaw)
• Symptoms of Tetanus (Lockjaw)
• Clinical Examination of Tetanus (Lockjaw)
• How is Tetanus (Lockjaw) Diagnosed?
• Prognosis of Tetanus (Lockjaw)
• How is Tetanus (Lockjaw) Treated?
• Tetanus (Lockjaw) Prevention
• Tetanus (Lockjaw) References

What is Tetanus (Lockjaw)

Tetanus is a disease caused by the toxin of the bacterium Clostridium tetani that affects the central nervous system, sometimes resulting in death. Spores of the bacterium C. tetani live in the soil and are found around the world. In the spore form, C. tetani may remain dormant in the soil, and it can remain infectious for more than 40 years.

Statistics on Tetanus (Lockjaw)

Tetanus causes approximately five deaths per year in the US. Internationally, reports show up to 1 million cases annually, mostly in developing countries. Tetanus infections in newborns accounts for about half of tetanus-related deaths in developing countries.

Risk Factors for Tetanus (Lockjaw)

Infection begins when the spores are introduced into an injury or wound. Any contaminated wound (e.g. a dirty nail, glass, metals etc.) is at risk of introducing a tetanus infection. The wound is often minor – e.g. sustained while gardening.

Progression of Tetanus (Lockjaw)

The organism produces a potent neutoxin, tetanospasmin. It acts to stimulate the sympathetic nervous system resulting in marked flexor muscle spasm and autonomic dysfunction.

Clinical Examination of Tetanus (Lockjaw)

There are several forms of the disease.

Generalised tetanus

(The most common form) There is general malaise followed by trismus (lockjaw). Spasm of the facial muscles produces the characteristic grinning expression rinus sardonicus. When the disease is severe there are painful reflex spasms (usually within 24-72 hours of the initial symptoms). The spasms may occur spontaneously or be precipitated by noise, handling of the the patient, or by light. Laryngeal spasm may impair breathing, oesophageal spasm lead to dysphagia and urothelial spasm lead to urinary retention. There is also arching of the neck and back muscles (opisthotonus). Death may result from aspiration, hypoxia, respiratory failure, cardic arrest or exhaustion. However, mild cases with rigidity usually recover.

Localised tetanus

(A milder form of tetanus) There is pain and stiffness at the site of the wound and increased tone in the surrounding muscles. Recovery is usual.

Cephalic tetanus

(Uncommon) Occurs when the portal of entry is the middle ear. There are cranial nerve abnormalities and there is invariably death following.

Neonatal tetanus

Occurs due to infection of the umbilical stump. The infant fails to thrive, has poor sucking, grimacing and irritability rapidly followed by intense rigidity and spasms. The disease is nearly always fatal.

How is Tetanus (Lockjaw) Diagnosed?

Diagnosis is by clinical examination, although C. tetani may occasionally be isolated from wounds. The diagnosis is normally clear though occasionally other conditions can mimic tetanus – e.g. meningitis, strychnine poisoning, phenothiazine overdosage.

Prognosis of Tetanus (Lockjaw)

Improvement in nursing techniques has reduced the mortality rate from 60% to 20%. 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.

How is Tetanus (Lockjaw) Treated?

• The wound must first be cleaned and debrided if necessary, to remove the source of the toxin.
• Human tetanus immunoglobulin 250 units should be given with an intramuscular injection of tetanus toxoid. If the patient has already been protected, a booster dose of the toxoid should be given, otherwise the full 3-dose course of the toxoid must be given.
• Treatment is supportive and patients should be nursed in a quiet, isolated, well-ventilated, darkened room.

Medications

• Benzodiazepines can be used to control spasm and sedate the patient.
• Intubation and mechanical ventilation may be necessary if the airway is compromised.
• Intravenous metronidazole is the drug of choice, although penicillin may also be given.
• HTIG 250IU (or if unavailable, immune equine tetanus immunoglobulin 10 000 IU) should also be given to neutralise the circulating toxin.

Tetanus (Lockjaw) Prevention

Tetanus is preventable by immunisation and should be administered to all ages.

Farmers are at a high risk of the disease and should have regular booster injections.

Immunisation should be active as passive immunisation may only last for 2 weeks. 2 doses of 0.5mL of the toxoid should be given intramuscularly at 8-week intervals. 6-12 months later the 3rd dose is given as a booster. Boosters are then required at 5-year intervals.

Tetanus (Lockjaw) References

1. Kumar P, Clark M. Clinical Medicine. Fourth Ed. WB Saunders, 2002.
2. MEDLINE Plus