Emergency War Surgery NATO Handbook: Part II: Response of the Body to Wounding: Chapter XI: Infection
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Tetanus is a severe infection caused by Clostridium tetani and its toxin's effects on the nervous system. It carries a mortality rate of approximately 50%. In an analysis of Vietnam War wound infections, no cases of tetanus were reported. The infection is characterized by local and general convulsive spasms of the voluntary muscles. Clostridium tetani is a strict anaerobe which exists in spore form in the soil and in the intestines of animals and man. Local necrosis and ischemia provide the conditions necessary for contaminating spores to evolve into their vegetative form and multiply rapidly at the site of infection. Once the vegetative forms have begun to multiply, large amounts of tetanus toxin are produced.
The incubation period is usually 6-12 days but may vary from 4-21 days or longer. In any event, the incubation period is sufficiently long to prevent the development of tetanus in war wounds if proper prophylaxis is employed within a day or two of injury.
Small, deep puncture wounds that often appear trivial are important sources of this infection and must be considered prone to tetanus. Early clinical manifestations may be of a general nature, such as irritability, insomnia, muscular tremors, local spasm, or rigidity in the muscle near the wound. Trismus is usually the first symptom. Sore throat, painful dysphagia, stiff neck, and difficulty in beginning micturition may be early evidence of muscular irritability. The dental officer may be the first to see the patient if trismus has been mistaken for some oral condition.
Trismus and risus sardonicus resulting from spasm of the masseters and muscles of the face are signs of established tetanus. Arching of the spine (opisthotonos) and respiratory difficulty from laryngeal and intercostal muscle spasm may also be present. The contractions are aggravated by additional spasms whenever any sensory excitation occurs. Usually reflex spasms are brought on by external stimuli, such as moving the patient or striking the bed, but later they occur spontaneously at regular and increasingly frequent intervals until the height of disease is reached. Spasms often begin with a sudden jerk. Every muscle in the body is thrown into intense tonic contraction; the jaws are tightly clenched, the head is retracted, the back is arched, the chest and abdomen are fixed, and the limbs are usually extended. A severe spasm may result in respiratory arrest. Spasms may last a few seconds or several minutes. When spasms occur frequently, they lead to rapid exhaustion and sometimes to death from asphyxiation. Without spasms, mortality is low. Few patients with severe spasms survive.
Cephalic tetanus is a form of tetanus in which irritation or paralysis of cranial nerves appears early and dominates the picture. The facial nerve is affected most often. Ophthalmoplegia from involvement of the ocular nerves may develop. Trismus and dysphagia may also follow wounds of the head and face, and the symptoms often appear first on the injured side.
Severe tetanus is often fatal, but those who recover do so completely without sequelae. The patient who has survived tetanus is not immune and, unless immunized, is susceptible to a second attack. Recurrent tetanus in the same patient has been reported. Apparently a sublethal amount of tetanus toxin is not sufficient to provide an adequate antigenic stimulus for production of active immunity.
The diagnosis of tetanus is a clinical one, with bacteriological confirmation sometimes possible. The morphologic appearance of the organism in stained smears (the so-called tennis racket terminal spore in Gram-positive bacillus) usually is not sufficient to differentiate Clostridium tetani from other anaerobes with terminal spores. The disease proceeds with fever, sweating, and oliguria while the mind remains clear. Death usually occurs as a result of respiratory arrest during painful generalized convulsions. Toxemia, pneumonia secondary to aspiration, hyperpyrexia, and cardiac failure are other causes of death.
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