Clostridium tetani (C. tetani)

Tetanus is a bacterial infection caused by C. tetani.20 C. tetani is found primarily in soil, dust and animal feces. Its spores enter the body through non-intact skin, usually cuts or puncture wounds caused by contaminated objects. Less commonly, tetanus has been linked to clean superficial wounds, chronic sores, insect bites, dental infections, compound fractures with exposed bone, and intravenous (IV) drug use.

The incubation period of C. tetani is usually 3–21 days, although it may range from 1 day to several months, depending on the character of the wound. Most cases occur within 14 days. In general, with heavy wound contamination the incubation period is shorter, the disease is more severe, and the prognosis is poorer. The spores germinate under anaerobic conditions and produce tetanospasmin, a powerful toxin.

Clinical Features

Tetanospasmin is disseminated via the vascular and lymphatic systems to the central nervous system, including peripheral motor end plates, spinal cord, and brain and the autonomic nervous system. The typical clinical features of tetanus are caused when tetanus toxins interfere with the release of neurotransmitters, blocking inhibitory impulses. This leads to unopposed muscle contraction and spasm.

“Hallmark” manifestations of tetanus include muscle stiffness and spasms (cramping) in the jaws, neck, and abdominal muscles. Other signs and symptoms may include fever, sweating, difficulty swallowing, elevated blood pressure, and rapid heart rate. Complications may include long bone fractures, laryngospasm, difficulty breathing, aspiration pneumonia, and blockage of the main artery of the lung or one of its branches by a blood clot (pulmonary embolism).

Prevention

Tetanus is a vaccine-preventable infection. There are four combination vaccines available to prevent diphtheria, tetanus and pertussis: DTaP, Tdap, DT, and Td. Two of these (DTaP and DT) are given to children younger than 7 years of age, and two (Tdap and Td) are given to older children and adults. A booster dose of Td is recommended every 10 years. Alternatively, one lifetime booster dose of Tdap may be administered.

Medical Management

Tetanus requires hospitalization, immediate treatment with human tetanus immune globulin (TIG) or equine antitoxin (if human immune globulin is not available), a tetanus toxoid booster, drug therapy to control muscle spasm and infection, and aggressive wound care. Depending on the severity of the disease (localized versus generalized tetanus), mechanical ventilation and drug therapy to control autonomic instability may be required. About 10-20% of the cases are fatal.