TETANUS or LOCKJAW, a disease caused by the toxin of Bacillus tetani (see BACTERIA AND DISEASE), an anaerobic bacillus found in soil contaminated by horse dung and therefore in the dust of streets and of gardens and other cultivated land. The bacilli or their spores gain access to the body through a breach of the surface, perhaps trivial, and remain localized. The toxin they elaborate travels by the sheaths of local nerves up wards affecting the nerves themselves in its course towards the spinal cord. Ultimately nerve cells are affected. The necessary conditions for multiplication of the bacilli locally are afforded by the dirt and other micro-organisms gaining access to the wound with the tetanus bacilli. Tetanus may affect persons at any age, even the newly born infant, but is commonest in male adults ; in hot countries it is more common, largely because the natives go barefoot. Horses are very liable to the disease.
In man the first symptom is stiffness in the back of the neck or the muscles of the jaw and face. There is difficulty in opening the mouth and the corners of the mouth are drawn downwards and backwards and fixed in that position (risus sardonicus). The jaw is so firmly set that it is impossible to pass anything between the teeth. Soon difficulty in swallowing comes on because the muscles of the throat are involved and the abdominal muscles are rigidly fixed. The muscles of the limbs are attacked by agon izing cramps, and, last of all, the muscles of the chest are in volved. Though all the muscles are in a continuous state of con traction, thereby differing from strychnine poisoning which tetanus otherwise resembles, the spasmodic contractions come on in addi tion, and occasionally are so severe that the patient is doubled up forwards, backwards or sideways and perhaps some of the muscles tear across. These spasms may be induced by very slight causes, a sudden small noise, a breath of wind, shaking of the bed.
The sooner the symptoms come on after the injury the worse is the prognosis of tetanus. In the absence of antitoxin treatment
when they arise within a week of the injury the prospect of re covery is extremely remote ; if within ten days the prospects are bad ; if they do not come on until three weeks or so after the injury there is hope. As shown below the prognosis is much im proved by prophylactic antitoxin treatment. In the developed disease antitoxic serum is of doubtful value even though injected intrathecally by lumbar puncture. The only available treatment is absolute quiet in a darkened room, morphia to relieve pain, and such amount of liquid food as will sustain life.
In Nov. 1914 preventive inoculation, introduced about the mid dle of Oct. 1914, had begun to exercise its beneficial effects. The following figures giving the number of cases of tetanus per 1,000 wounded men make this clear: The same experience was met with in the French and German armies. As soon as preventive inoculation with anti-tetanic serum became a universal practice, the incidence of tetanus dropped sharply and remained small. In June 1917 it was ordered that each wounded man should receive not one inoculation as formerly but four, at intervals of a week, because the minimizing effect of the serum passes away rather quickly.