Tetanus
Tetanus, sometimes called lock-jaw, is an acute disease caused by a neurotoxic exotoxin of the bacteria, Clostridium tetani. Effective vaccines are available for prevention of tetanus.
The disease and its agent
Tetanus, sometimes called lock-jaw, is an acute disease caused by a neurotoxic exotoxin of the bacteria, Clostridium tetani. The disease is now fairly uncommon in most industrialised countries but may be a more significant cause of death in some countries, including parts of Asia, Africa and South America. World-wide, mortality rates vary considerably (10-90 per cent), largely being influenced by the length of incubation and availability of treatment. Highest fatality occurs in infants and elderly people. In Australia death occurs in about 10 per cent of cases.
Early symptoms of infection with C. tetani include localised peripheral nerve and muscle spasms eventually causing generalised spasms and convulsions. Painful muscular contractions of the masseter, neck and trunk muscles, and facial spasms known as "risus sardonicus" are experienced in the advanced disease. The muscle rigidity with superimposed painful spasms occurs after an incubation period of 3-21 days, most often after 7-10 days. Death usually results from respiratory failure, hypertension, hypotension or cardiac arrhythmia.
Spread of infection
C. tetani (a bacillus) is a normal and harmless inhabitant of many animals (eg. horses) and humans and is a common environmental organism found in soil. Infection with the bacillus may occur after minor incidents (sometimes unnoticed punctures to the skin) or after major injury: compound fractures; wounds containing foreign bodies, especially wood splinters; wounds complicated by pyogenic infections; wounds with extensive tissue damage, e.g. contusions or burns; any superficial wound obviously contaminated with soil, dust or horse manure, especially if topical disinfection is delayed more than 4 hours. Tetanus is not directly transmitted from person to person.
Prevention
Effective vaccines are available for tetanus. The vaccine is an inactivated cell-free tetanus toxin (toxoid) which is available in Australia as DTP, CDT, and Td (ADT). DTP is a combined diphtheria, tetanus and pertussis vaccine. Tetanus immunisation should normally be part of the standard childhood vaccination schedule. Although immunity following complete vaccination is long lasting, maintenance of immunity with booster doses at 10 year intervals is recommended. Tetanus immunoglobulin (TIG) provides passive protection where an unimmunised person has sustained a tetanus-prone wound. Tetanus immunoglobulin is also available for the management of clinical tetanus. This product is prepared from human plasma containing high antibody levels to the tetanus toxin.
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