– An acute infectious disease of the central nervous system characterized by intermittent tonic spasms of the voluntary muscles.
Causes and Incidence
Tetanus is caused by the tetanospasmin exotoxin produced by the spore-forming Clostridium tetani bacillus. The organism enters the body through a wound contaminated with soil and feces containing viable spores. The incidence is sporadic, and the disease occurs worldwide. It is rare in developed countries, where immunization is common.
The bacillus spores enter and multiply in a skin wound to produce the tetanospasmin toxin. The toxin travels to the central nervous system via the bloodstream and peripheral motor nerves and binds to ganglioside membranes, blocking release of an inhibitory transmitter. This induces a hyperexcitability in the motor neurons that results in tonic rigidity and spasms of the voluntary muscles. Once bound, the toxin cannot be neutralized by an antitoxin.
The incubation period ranges from 2 to 50 days, with an average of 5 to 10 days before symptoms occur. The most common symptom is stiffness of the jaw. Others include irritability, restlessness, headache, fever, sore throat, stiff neck, and difficulty swallowing. As the disease progresses, the person has difficulty opening the mouth, facial spasms, and rigidity with a fixed grin; opisthotonos; painful, generalized tonic spasms; profuse sweating; cyanosis; and exaggerated reflexes.
The worldwide mortality rate is 50%, and prognosis is poor when the incubation period is short and the symptoms progress rapidly. Complications include cardiac and pulmonary failure and muscle rupture.
The diagnosis is made by history and physical examination. Blood and wound cultures and tetanus antibody tests are commonly negative.
Debridement of deep penetrating wounds; tracheotomy if needed for prolonged respiratory management.
Tetanus toxoid with subsequent booster shots for primary immunity; tetanus antitoxin or tetanus immune globulin may be given at time of penetrating injury with no history of recent vaccination; muscle relaxants to treat rigidity and spasm; antiinfective drugs for infection; analgesics for pain.
Prompt, thorough debridement of wound; intubation and mechanical ventilation if needed; tube feedings or hyperalimentation to manage nutrition; catheterization to manage urinary retention; coughing, turning, deep breathing to prevent pneumonia; cardiac and hemodynamic monitoring; adequate fluids and electrolytes; instruction in the importance of maintaining immunization with routine booster every 10 years.