CAUSED BY the anaerobic, spore-producing Clostridium tetani bacterium, tetanus is an acute and potentially fatal disease that usually originates in a wound. Common in soil, C. tetani spores may also be found in the intestinal tracts of humans and animals.
Tetanus occurs when C. tetani spores enter the body through an opening in the skin. In anaerobic conditions (as may occur with deep or puncture wounds), the spores germinate and produce an endotoxin called tetanospasmin, which is disseminated by the bloodstream and lymph system. Acting on the brain and spinal cord, this endotoxin causes muscle rigidity and painful muscle contractions. Besides wounds (including burns), tetanus is associated with injection of contaminated street drugs.
The incubation period for tetanus ranges from 3 to 21 days, with an 8-day average. Severity of illness is related to the amount of infecting dose absorbed. Recovery from tetanus disease doesn't confer immunity from future infection. Thanks to widespread immunization, however, tetanus is rare in the United States today.
Wound cultures for C. tetani are unreliable because the bacterium is recoverable from only about 30% of infected wounds, and C. tetani is sometimes recovered from patients who don't have the disease. So the health care provider will base her diagnosis on a patient's history and his signs and symptoms.
Initially, the patient may report muscle stiffness of the jaw (trismus or lockjaw), neck stiffness, sore throat, dysphagia, and abdominal muscle rigidity progressing to generalized muscle stiffness. Other signs and symptoms include tremors, spasms, contraction of the facial muscles (causing an involuntary smile or grin called risus sardonicus), fever, hypertension, intermittent tachycardia, and diaphoresis.
Spasms and stiffness may be either localized at the injury site or widespread and may be triggered by sensory stimuli, such as noise or touch. Spasms of the vocal cords and respiratory muscles may interfere with breathing and lead to respiratory failure, requiring neuromuscular blockade and prolonged respiratory support. Other treatment includes supportive therapy to control spasms and protect the airway, meticulous wound care to remove spores, and administration of tetanus immune globulin to help remove unbound endotoxin.
Fortunately tetanus is completely preventable through vaccination with tetanus toxoid. Encourage patients to complete a vaccination series and to maintain immunity with a booster every 10 years.
Whether a patient needs tetanus toxoid (active immunization) after an injury, with or without tetanus immune globulin (passive immunization), depends on the wound and the patient's immunization history (see How to Treat Your Patient after an Injury). Diphtheria toxoid is given with tetanus toxoid because most adults don't keep up with diphtheria boosters. Tetanus prophylaxis should be given even if several days have passed. The only contraindications for tetanus and diphtheria toxoids are a neurologic reaction or a severe hypersensitivity response following a previous dose.
For vaccination schedules recommended by the Centers for Disease Control and Prevention, go to http://www.cdc.gov/nip/diseases/tetanus/vac-chart.htm.
Barbara Wyand Walker is an infection control/employee health nurse at Greenbrier Valley Medical Center in Ronceverte, W.Va.
Did you know?
Tetanus is the only vaccine-preventable disease that's infectious but not contagious.