Clinical Features and Criteria of Severity in Tetanus
Clinical Features If circulating antibodies are present, immune elimination may be very rapid and may be accompanied by fatal anaphylaxis. The dose of equine antitoxin for prophylaxis is 1500 units, but prophylactic antitoxin should not be given if either local or general reactions follow the subcutaneous injection of a test dose of 75 units. Epinephrine, 1 per 1000, should always be available whenever equine antitoxin is given; in cases in which anti-toxin is indicated and either a history of previous injections of horse serum or a reaction to a test dose has been elicited, prophylaxis with human anti-tetanus immunoglobulin, 250 units, will be more effective and much safer.
Chemoprophylaxis. Antimicrobial drugs can inhibit the multiplication of Clostridium tetani and kill the vegetative form of the organism. By kill 44ng aerobic organisms coexisting with the Clostridium,.antimicrobial drugs can prevent multiplication by .denying the Clostridium the conditions favorable to its growth; they have no effect, however, on tetanus toxin. Because of the dangers of passive immunization, some centers in the United Kingdom have largely abandoned the use of anti-toxin in favor of .chemoprophylaxis, and at least one of these has provided data showing no increase in the incidence of the disease. Although the efficacy of chemoprophylaxis is not yet certain, it seems clear that in certain circumstances it may provide an alternative to prophylaxis by anti-toxin.
Clinical Features For effective chemoprophylaxis certain criteria must be fulfilled: the organism must be susceptible to the drug chosen, and the patient must not be sensitive to the drug. Clostridium tetani are susceptible to a variety of drugs, including penicillin, tetracycline, and erythromycin so that it is probably not difficult to make a suitable choice for a particular patient. Chemoprophylaxis must be started early. Smith (1964) has shown that in mice inoculated with tetanus spores, chemoprophylaxis was effective if it was started four hours after inoculation but not if started eight hours after inoculation. The time interval in humans is not established, but it is suggested that in injuries seen later than six hours after infliction, some other form of prophylaxis should be chosen. Anti-microbial therapy must be continued for a sufficient time to ensure that tetanus spores cannot survive, and this means for at least five days.
If tetanus is to supervene, the Clostridium must be introduced into human tissue, and the disease may follow a trivial or a serious injury. In countries with good medical services, serious wounds receive effective treatment, and tetanus is usually avoided. Apparently minor wounds then become a common cause of the diseases, but in quite a high proportion of cases, no responsible injury can be identified. The site of action and method of spread of the exotoxin has been mentioned, but it • is rather surprising that no unequivocal evidence of recognizable pathologic lesions caused by titan has yet been forthcoming even after careful post-mortem studies.
Clinical Features Features and Criteria of Severity in Tetanus
The criteria of severity may be established in two ways: from history and from the symptoms and signs. From History. The severity of an attack of tetanus is related to the incubation period (the period from injury to the first sign of tetanus) and the onset period, described by Cole (1940) as the period from the first sign to the first generalized spasm. If the former is less than 9 days and the latter less than 48 hours, the attack of tetanus may be expected to be severe. The length of the onset period is, in general, the more reliable guide to the expected severity of the attack. From the Symptoms and Signs. The Mild Case. Tetanus usually presents with the rigidity of muscles, and this rigidity may be severe enough to cause pain.
The patient with mild tetanus may have “local tetanus” in which rigidity affects only one limb, or the patient may have mild generalized rigidity. Stiffness of the jaw muscles causes tris-mus, and stiffness of .the facial muscles may cause a change of expression. Stiffness of the muscles of the neck and back may cause discomfort or even pain on attempted flexion of the spine. The Moderate Case. The patient has more severe generalized rigidity. Trismus is pronounced, the mouth can hardly be opened, and rigidity of the ‘muscles of the face may cause the sneering “risus sardonicus.” Opisthotonos may be pronounced, but more typically the stiffness of the antagonist's muscles makes the patient lie “at attention” in bed, and the muscles of the back and abdomen are hard to the touch.
Patients with moderate tetanus may Show mild exacerbations of this generalized rigidity as “reflex spasms.” These spasms may arise spontaneously or more commonly as a result of stimuli. The important difference, however, between the patient with mild and the patient with moderate tetanus is the presence or absence of dysphagia. Spasm of the pharyngeal muscles makes swallowing difficult, and the patient coughs or splutters while drinking. This will predispose to the inhalation of Sharon-goal contents and is the diagnostic characteristic of the moderate case.
The Severe. Case. The patient who represents a severe case is distinguished from the patient with a moderate case by the presence of reflex spasms that may be of appalling intensity. If the spasms are untreated opisthotonos becomes extreme, and the intense muscle spasm may fracture vertebrae. Spasm of the laryngeal muscles, the diaphragm, and the intercostals prevents ventilation, and cyanosis occurs. The occurrence of reflex spasms that cause cyanosis and cannot be controlled except by powerful relaxants such as