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[Gr. tetanos, stretched]
An acute, life-threatening illness caused by the toxin tetanospasmin, produced in infected wounds by the bacillus Clostridium tetani. The disease is marked by extreme muscular rigidity, violent muscle spasms, and often, respiratory and autonomic failure. Because of proactive immunization programs in the U.S., the disease affects only 50 patients annually. In nations without effective immunization programs, the disease is very common and usually deadly.
SEE: Clostridium tetani; SEE: lockjaw; SEE: tetanolysin; SEE: tetanospasmin; SEE: trismus
The responsible bacteria is most likely to proliferate in tetanus-prone wounds, e.g., those contaminated by soil, animal excrement or debris; puncture, avulsion, or bite wounds; burns; frostbite; necrotic tissues; gangrene; injection site infections; umbilical stump infections; or uterine infections. It is less likely to infect shallow wounds with cleanly cut edges. The spores of C. tetani germinate in the anaerobic depths of tetanus-prone injuries, producing bacteria that release tetanospasmin. This neurotoxin is carried to the central nervous system, where it blocks impulses that modulate muscle contraction. The incubation period varies from 1 or 2 days to a few months. The shorter the incubation, the more deadly the illness is likely to be.
Unopposed muscular contraction leads to rigidity and spasticity, esp. of the muscles of the jaw, neck, back, abdomen, and esophagus. Lockjaw (trismus) is a hallmark of the disease, as are violent arching of the back muscles (opisthotonus), and a rigid, fixed smile (risus sardonicus). Intense painful muscle spasms may be triggered by noises, bright lights, attempts to swallow or eat, or other stimuli. The patient may also suffer profuse sweating, low-grade fever, and wild fluctuations in pulse, blood pressure, and respirations. Diagnosis usually is based on a history of trauma with no previous tetanus immunization and on the clinical picture presented.
Early débridement may lessen the burden of toxin-producing bacteria in the wound. Muscle-relaxing drugs, like baclofen and diazepam, and neuromuscular blocking agents, such as vecuronium, reduce muscle spasm. Beta blockers like propranolol decrease the incidence of tachycardias and hypertension. Advanced airway and ventilatory support are best provided in an intensive care unit. Tetanus immune globulin is given to provide passive immunity against circulating tetanus toxin. High doses of penicillin G (or alternatives for the patient with penicillin allergy) are administered intravenously to kill clostridia. Wound debridement and/or surgical exploration may be required to remove the source of the toxin.
The patient is kept in a quiet, dimly lit room, where stimulation is minimized. A patent airway is maintained, oxygen administered to maintain oxygen saturation, and suctioning carried out gently with prehyperventilation and posthyperventilation. Oral feedings are withheld to limit esophageal spasms and the aspiration of nutrients. Intravenous access is established for administration of emergency medications, and hydration is provided. Enteral or parenteral nutrition may be needed to meet the patient’s increased metabolic needs. A Foley catheter is placed to prevent urinary retention. Cardiac rhythm and vital signs are monitored, and fluid and electrolyte balance managed.
Recovery from tetanus does not guarantee natural immunity. Therefore, the patient should begin an immunization series before leaving the hospital.
Initial immunization should begin in infancy. The toxoid should be given in three doses at 4- to 8-week intervals beginning when the infant is 6 to 8 weeks old, and a fourth dose 6 to 12 months thereafter. A fifth dose is usually administered at 4 to 6 years of age before school entry. Tetanus toxoid is commonly given in combination with diphtheria toxoid and acellular pertussis vaccine. Active immunization with adsorbed tetanus toxoid provides protection for at least 10 years. Although it has been the practice to give a tetanus booster every 10 years, current advice is to give a single booster dose at age 50 if the individual received all 5 doses as a child. Tetanus booster vaccination should be given to patients with tetanus-prone wounds who have not received the toxoid in the past 3 years.