TETANUS

The normal habitat of Cl. tetani is the intestinal tract of "horses, cows and other herbivora. The bacilli are sometimes found in human faces. Heavily manured soil is particularly liable to be contaminated with the highly resistant spores of this angerobe. Introduced through a punctured wound commonly made by a splinter or nail, the bacilli or spores—particularly in the presence of pyogenic infection, laceration of tissues or a foreign body—tend to multiply and produce the powerful toxin which acts on the nervous system.
Although the potential risk of tetanus following deep wounds is well recognized, the very real danger of infection following superficial septic abrasions in children or mild septic skin lesions in farm workers is not sufficiently appreci­ated. Imperfectly sterilized catgut has been responsible for the development of post-operative tetanus.
Early diagnosis is very important. Stiffness of the jaw, pain in the neck or back increased by manipulation and associated with the characteristic facial expression should lead to immediate specific treatment.
Tetanus is not a notifiable disease. The length of the incubation period varies greatly and the duration from the onset of symptoms until the appear­ance of definite spasms has a very important bearing on prognosis. An incubation period of less than seven days indicates a severe case. When the prodromal period is less than twenty-four hours a fatal outcome is almost invariable.
Preventive Treatment.—Passive immunization is an effective measure, but it must be understood that the method has its limitations. First, it must be carried out at the time of injury. Delay is dangerous. Secondly, passive immunization only lasts for two to three weeks, so that the patient could emerge from his temporary cover before the incubation period had elapsed, though by this time florid tetanus would be unlikely to develop. Thirdly, and most important, persons who have previously received horse serum in some form may develop serum sickness; such persons are liable to eliminate the antitoxin more rapidly, thus reducing the period of " cover ". To these factors must be added the doctor's natural reluctance to administer antitoxin when a wound is appa­rently trivial—yet such wounds may be infected by tetanus.
In view of these considerations, two alternatives may now be considered. If the patient is seen at the time of wounding it may be assumed that the formation of tetanus toxin has not started. After the wound has been thoroughly opened and cleansed prophylactic tetracycline is given for one week. A dose of ro g. per day will suffice. Antitoxin is not administered. On the other hand, if some time has elapsed between the wounding and the patient being seen by the doctor, antitoxin is imperative as a first step. A dose of 1,500 units intramuscularly is given. At the same time active immunization with ro ml. of adsorbed tetanus toxoid is begun.Such ideal alternatives do not allow for the fact that more than half of the cases'of tetanus occur as a result of trivial wounds which never called for medical supervision. To some extent this might imply the success of passive immuniza­tion. The most important aspect of the argument, however, is that it underlines the need for active immunization. If this is given first in infancy in the form of triple vaccine, repeated at 18 months and again at school entry (when only diphtheria and tetanus toxoids need be given) the risk of tetanus is reduced to a minimum. In such persons the correct treatment, when wounding occurs years later, is the administration of a booster injection of ro ml. of tetanus toxoid.
Finally, when a first injection of toxoid is given at the time of wounding (as part of the active-passive immunization) all necessary steps should be taken to ensure that the family doctor is informed so that he may complete the course with a second injection six weeks later.
Curative Treatment.—The management of a case of tetanus is nearly always a complex problem. Although there can be no accepted routine, satis­factory7 treatment will generally involve four main considerations.
The spasms are, of course, the result of the specific effect of tetanus toxin, so that its neutralization seems an obvious and immediate concern. It must be realized, however, that by the time the diagnosis is established much of the toxin is " fixed " and is beyond the reach of antitoxin. But since toxin is still being formed by the bacilli in the tissues it is essential to obtain the advantage of passive immunization as quickly as possible, and in order to achieve this a dose of 20,000 units is adequate. After an initial intramuscular injection of half the dose the remainder should be given intravenously. (Before proceeding with the injection of serum the details on p. 50 should be consulted.) It should be remembered that when the patient develops a serum reaction (either immediate or delayed), the excretion of antitoxin is hastened. If this should occur, repeated doses of 1,500 units of antitoxin intramuscularly should be given every second or third day. It must be appreciated that antitoxin is given more to promote passive immunization than for curative purposes.
In many cases there is an indication of the causative wound. Often this will have closed or there may be evidence of deep ramifications into the tissues to produce conditions which encourage an anasrobic situation. Whenever possible, the wound should be excised and freely opened and the opportunity taken to ensure the removal of any necrotic tissue or foreign material. The wound should then be left open, although every attempt must be made to prevent any further bacterial infection. Large doses of penicillin (i to a mega units per day) should be given parenterally.
The next problem is to secure adequate sedation of the patient. It is always desirable to set up at once an intravenous drip in order to ensure adequate hydration and, at least to begin with, 5 per cent. glucose in saline will prove sufficient. The drip tube can be used for the intravenous administration of sedatives. Thiopentone (0-5 to i g.) may be added to each pint (600 ml.) in the drip bottle, and this will serve for continuous basal sedation. A syringe containing o-i to 0-3 g. of thiopentone is retained at hand and this can be injected into the drip tube when there is need for nursing or medical attention or to cover very severe spasms. In the more severe cases when sedation has to be prolonged there is a possible danger of toxic reaction to a build-up of thio­pentone and, for this reason, it should be reserved for the early stages only when the patient is being assessed and wound toilet being carried out. Some recent—and apparently severe—cases have been managed very satisfactorily with chlorpromazine or promazine given intramuscularly. These drugs can be given in divided doses to a total daily amount of up to 2-0 g. without apparent toxic effect, and in some cases it has proved possible to stop the thiopentone and depend upon the promazine alone. A syringe containing thiopentone should remain at hand, however, to control the more severe spasms. Should thiopentone or a promazine derivative or a combination of them prove insuffi­cient, it will be necessary to resort to muscle relaxants. Since the principles involved are those of modern anaesthetic practice, it will be obvious that the management of this aspect of the problem demands that an anassthetist should be consulted at once in the early stages. It then becomes possible to proceed step by step from the simplest to the most complicated methods.
With the degree of sedation necessary to secure freedom from spasm, the maintenance of a clear airway becomes the next problem. In all but the mildest cases an elective tracheostomy should be performed and a cuffed endotracheal tube inserted. This ensures that the risk of anoxia from laryngeal spasm is eliminated, or at least greatly reduced, and avoids secretions passing from the pharynx downwards. Tracheostomy alone is of great value in the more effective control of the patient who is moderately to severely ill; it is, of course, essential when the need arises for muscle relaxants for it then becomes simple to change over to mechanical respiration.
Enough has been said to emphasize the point that the treatment of tetanus is a very elaborate procedure. There is no doubt that the institution of such specialized methods has greatly improved the prognosis even in the most severe cases. The progress to recovery of such cases makes it necessary to point out certain features of tetanus that were previously not observed. First, during the acute stage, periods of pyrexia—indeed hyperpyrexia—are sometimes seen. This is best managed by leaving the patient uncovered and by the use of fans. Secondly, it seems likely that late toxic effects on other organs of the body— notably the heart—may be encountered. Convalescence should, therefore, not be hastened. Finally, it should be realized that the patient who has recovered from tetanus is not necessarily immune. Since his occupation may expose him to further risk it is important, when the stage of complete recovery is reached, to proceed with a programme of active immunization with toxoid.
General Management.—The patient should lie on a sponge-rubber mattress with the bedclothes supported by a cradle. Isolation is not essential. Trained day and night nurses are necessary. Noise must be excluded, the sickroom darkened and nursing duties performed quietly and preferably at times when the patient is deeply under sedatives.
A minimum daily food intake of 2,000 calories in an adult patient is a highly important part of the treatment, but it is very difficult to attain. One of the main duties of the nurse is to feed the patient who is only mildly affected at hourly or even half-hourly intervals with milk, egg flip, thin gruels and glucose lemonade. In severe cases feeding should be carried out through a nasal tube left in position or supplemented by the intravenous administration of 5 per cent. glucose saline by the drip method. The use of a composite food such as Corn-plan (Glaxo) makes the calculation of caloric intake simple and tube feeding by mouth is given greater precision.The bowels should be moved by enemata, and retention of urine watched for and relieved by catheterization.