A Suitable Dosage Regimen, Including Subcutaneous, Intramuscular
Intramuscular Curare and IPPV. Curare and similar powerful relaxants will completely abolish the reflex spasms of the severest case of tetanus, but will also paralyze the muscles of ventilation. It is, therefore, necessary for addition to apply IPPV through a cuffed tracheostomy tube. Curare can be given intramuscularly in doses from 15 to 30 mg. Wound Excision. Wound excision has been dis-cussed under Prevention and seems a logical course of action if the causal injury can be identified. It has ‘been suggested that excision of the wound is ineffectual in established tetanus be-cause. all the exotoxin produced by the organism has been fixed by the nervous system before symptoms and signs develop.
Francis (1914) inoculated animals with tetanus and killed them when symptoms and signs began. He was able to recover many thousands of mouse lethal doses of toxin from the site of the inoculation Intramuscular, and this would seem to make the case for wound excision unassailed able. A careful search should be made for foreign bodies in any wound excised, and excision should probably be conducted under cover of antitoxin. Chemotherapy. Antimicrobial therapy has also been discussed under Prevention. As a therapeutic measure, all patients with tetanus should have large doses of penicillin or another active anti-microbial for a sufficient time to ensure that the Clostridium cannot survive. This should be for at least five days of Antitoxin.
The advisability of using equine antitoxin as a therapeutic measure has been a controversial matter for many years. There is some, but not clear-cut evidence that the use of equine antitoxin reduces mortality in established tetanus. On general grounds, however, the work of Francis cited above suggests that toxin is still being produced at the time when symptoms and signs begin, and hence it would seem reasonable to neutralize • any accessible toxin. Therapeutic antitoxin is subject to the same objectives and hazards as prophylactic antitoxin, and its dangers must be balanced against the possible gain by its use.
A suitable dosage regimen, including subcutaneous, intramuscular, and intravenous injections, should be designed to uncover sensitivity if present and to avoid anaphylaxis. Ten thousand units intravenously is a suitable dose, but up to 100,000 units have been used. If a history of previous injections of horse serum can be obtained or if a sensitivity reaction occurs, equine antitoxin should not be used. If available, human antitoxin in the same dose is more effective and much safer.
The patient with mild tetanus needs only these general measures, including a relaxant and sedatives such as diazepam. If a patient. coughs or Moderate Tetanus.
The patient with moderate tetanus differs from the mild case by the presence of dysphagia. to make inhalation of pharyngeal contents impossible. The operation is performed under general anesthesia with a cuffed endotracheal tube in situ so that the operation may be careful and unhurried. A cuffed tracheostomy tube should be inserted through a high U-shaped incision into the trachea so that the tube lies easily in the trachea where it is approximately parallel to the skin. If the tracheostomy is high, there is sufficient distance between the tracheostomy and the carina to make it unlikely that the tube will enter the right main bronchus.
The wound should not be covered and should be cleaned frequently with a mild anti-septic. The patients with moderate tetanus must be fed by a nasogastric tube and may require large amounts of fluid to offset excessive sweating. Patients with moderate tetanus may have a considerable degree of muscle rigidity and may even have occasional mild reflex spasms. Diazepam in divided doses of up to 400 mg. intravenously per day has a considerable effect on the rigidity of tetanus with-out interfering with ventilation. In spite of treatment, muscular rigidity is painful and uncomfortable, and the patient should be turned every two hours to lessen this discomfort and avoid pressure sores.
The patient with severe tetanus differs from the patient with moderate tetanus in that he has frequent reflex spasms that cannot be controlled by muscle relaxants other than curare, Curare may be given by the intramuscular injection of 15 to 30 mg.; if the patient must be paralyzed, there seems little to be gained by with-holding the drug. At Oxford, the nurses are instructed to give a further dose of curare when reflex spasms become obvious, and 400 mg. of curare per day has been necessary. The high incidence of pulmonary embolus in patients with severe tetanus has led to the use of anticoagulants