Tetanus

Notification requirement for tetanus

Tetanus is a ‘routine’ notifiable condition and must be notified by medical practitioners and pathology services in writing within 5 days of diagnosis.

This is a Victorian statutory requirement.

Primary school and children’s services centres exclusion for tetanus

Exclusion is not applicable.

Infectious agent of tetanus

Clostridium tetani, the tetanus bacillus, is the causative agent.

Identification of tetanus

Clinical features

Tetanus is an acute, potentially fatal disease caused by tetanus bacilli multiplying at the site of an injury. These produce an exotoxin that reaches the central nervous system and causes muscle stimulation.

The initial feature is increased muscle rigidity. This may be restricted to, or most pronounced in, muscles near the injury (localised tetanus). Depending on severity, muscle rigidity usually affects most parts of the body and is associated with hyper-reflexia. As a result, features such as neck, back and limb stiffness; stiff jaw or ‘lock jaw’ (trismus); and a sardonic smile (risus sardonicus) may occur.

With progression, superimposed painful muscle spasms can appear anywhere or involve most body muscles simultaneously. Opisthotonos can result. This is severe hyperextension and spasticity of the muscles of the head, neck and spinal column, causing arching. Painful spasms may become very frequent and, together with background rigidity, cause life-threatening interference with respiration.

Laryngeal spasm is a very serious complication that may occur at any stage and can cause sudden asphyxia. Exhaustion and inability to swallow are also associated with severe disease.

Case-fatality rates vary from 10 to 90 per cent, and are highest in infants and the elderly.

Diagnosis

Clinical features of severe classical tetanus are virtually diagnostic.

Laboratory confirmation of tetanus infection is often difficult.

C. tetani antibodies are sometimes detectable in serum samples but may result from waning past immunisation. Cultures from the site of infection should be attempted, although the organism is often not recovered.

Incubation period of Clostridium tetani

The incubation period is usually 3–21 days, although it may range from 1 day to several months, depending on the nature of exposure. Most cases occur within14 days.

Cases with shorter incubation periods tend to have more severe disease and thereby a greater risk of death.

Public health significance and occurrence of tetanus

Tetanus occurs worldwide but is now rare in developed countries because of high immunisation rates. Infection is most likely in older people who have never been immunised, or who have waning and inadequate immunity.

Tetanus is still common in developing countries with lower immunisation rates and where contact with animal excreta is more common. Tetanus, particularly neonatal tetanus, is a significant cause of death in these settings.

In 1989 the World Health Assembly committed to the elimination of neonatal tetanus. The World Health Organization estimates that, in 2008 (the latest year for which estimates are available), 59,000 newborns died from neonatal tetanus, a 92 per cent reduction from the situation in the late 1980s. The same year, 46 countries still had not eliminated maternal and neonatal tetanus (MNT) in all districts. Although progress continues to be made, by December 2010, 39 countries had not reached MNT elimination status.

Intravenous drug use is an independent risk factor for tetanus in the absence of acute injuries and may be linked to localised case clusters.

Reservoir for Clostridium tetani

C. tetani is widely distributed in cultivated soil, and in the gut of humans and animals. Spores can usually be found wherever there is contamination with soil.

Mode of transmission of Clostridium tetani

Tetanus is not directly transmitted from person to person.

Spores may be introduced through contaminated puncture wounds, lacerations or burns, or contaminated injected ‘street drugs’. Tetanus can result from minor wounds that are considered too trivial for medical consultation.

The presence of necrotic tissue or foreign bodies encourages the growth of anaerobic organisms such as C. tetani. Tetanus rarely follows surgical procedures today.

Period of communicability of tetanus

Spores may remain viable for many years in the environment.

Susceptibility and resistance to tetanus

Active immunity is produced by immunisation with tetanus toxoid and persists for at least 10 years after full immunisation.

Transient passive immunity follows injection of tetanus immunoglobulin (TIG) or tetanus antitoxin.

Recovery from tetanus is not necessarily associated with immunity.

Control measures for tetanus

Preventive measures

Tetanus toxoid is part of the standard childhood immunisation schedule. Primary immunisation for children begins at 2 months of age and requires three doses of tetanus toxoid–containing vaccine at 2-monthly intervals. Children should be given a booster at 4 years of age. A further booster dose is given between 15 and 17 years (year 10 at school), and again at 50–59 years of age. Individuals who received a primary course of three doses as adults should receive booster doses 10 and 20 years after the primary course.

For further information on tetanus vaccination, particularly with respect to the management of children who have missed doses, consult the current edition of The Australian immunisation handbook (National Health and Medical Research Council).

The use of tetanus toxoid in the management of wounds, with or without TIG, is determined by considering the vaccination history of the person and the nature of the wound. For further information on the management of bites and other tetanus-prone wounds, consult the current edition of Therapeutic guidelines: antibiotic.

Control of case

Refer the patient immediately to a specialised centre with intensive care facilities. The principles of treatment include:

• TIG by intramuscular injection
• tetanus antitoxin (where TIG not available)
• intravenous metronidazole for 7–14 days in large doses
• adequate (often wide) wound debridement
• careful attention to provide an adequate airway and to control muscle spasm
• case investigation to determine the circumstances of injury
• active immunisation provided concurrently with treatment.

Control of contacts

Not applicable.

Control of environment

Not applicable.

Outbreak measures for tetanus

Not applicable.