It involves muscular rigidity that stays throughout the illness. There are paroxysmal spasms of the voluntary muscles (lock–jaw), the facial muscles (risus sardonicus), the muscle of the back and neck (opisthotonus), and those of the lower limbs and the abdomen. Aspiration, respiratory failure, cardiac failure or exhaustion may cause death.
Poor prognostic signs are:
- Short incubation period (less than 5 days) between the time of injury and the onset of spasms.
- convulsions within 48 hours of the onset of muscle spasm
- post-partum or post-infection occurrence of tetanus
- occurrence in neonates or elderly
Tetanus is best prevented by active immunization with tetanus toxoid. The tetanus vaccine is either available in the combined form or just tetanus toxoid. The combined form of the vaccine is DPT (Diphtheria, Pertussis, Tetanus). Purified tetanus toxoid (absorbed) has largely supplanted plain toxoid because it stimulates a higher and longer lasting immunity response than plain toxoid.
A primary course of immunization consists of two doses of tetanus toxoid absorbed (each dose 0.5 ml, injected into the arm) given at intervals of about one to two months.
The first booster dose (the third in order) is recommended a year after the initial two doses.
Reactions following the injections of tetanus toxoid are uncommon. In persons presenting with a history of allergy, the usual precautions should be observed.
Storage of vaccine
Purified tetanus toxoid should be stored between 4 and 10°C. It must not be allowed to freeze at any time.
The role of immunoglobulins in tetanus
Immunoglobulins for protestation against tetanus are available either as human or animal derivatives. They are used in cases when the risk of tetanus is high e.g. open contaminated wounds as seen after road traffic accidents, septic abortions etc.
The dose of the Human Tetanus Hyperimmuneglobulin is 250–500 IU. If human immunoglobulin is not available horse derived serum can be used. The incidence of allergic reactions is much higher with animal derived serum. The standard dose is 1500 IU, injected subcutaneously after sensitivity testing.
Role of antibiotics in prophylaxis
Antibiotics are indicated in the prophylaxis against tetanus. Antibiotics should be given as soon as possible after an injury before a lethal dose of toxin is produced in the wound which may be as soon as 6 hours after injury.
Prevention of neonatal tetanus
To ensure protection from neonatal tetanus immunization of the mother during pregnancy is absolutely essential. Two doses of tetanus toxoid should be given, the first as early as possible during pregnancy and the second at least a month later and at least three weeks before delivery. In previously immunized pregnant women, a booster dose is considered sufficient in areas where the incidence of neonatal tetanus is high, the primary two–dose course can be extended to all women of childbearing age. Infants born to the mothers who have not previously received two doses of tetanus toxoid are exposed to the risk of neonatal tetanus. They can be protected by injection of antitoxin (heterologous serum, 750 IU) if it is administered within six hours of birth. Health care workers who attend to delivery cases in rural areas should be taught hygienic measures of conducting it. The umbilical cord should be tied and cut in a sterile fashion, and nothing should be applied to the stump. The practice of applying cow dung to the cord should be abandoned.
Prevention of tetanus after injury
All wounds must be thoroughly cleaned soon after injury – removal of foreign bodies, soil, dust, necrotic tissue.
Treatment of Tetanus includes intensive care, muscle relaxant drugs and often assisted ventilation.