The antitoxic serum is our sheet-anchor in the treatment of diphtheria, and recourse should be had to its use as early as possible.

Difficulty of swallowing may be met by the use of a stomach tube passed either through the mouth or nose.  When this is impracticable, nutrient enemata are called for.

In laryngeal diphtheria, the interference with respiration may call for intubation of the larynx, or tracheotomy, but the antitoxin treatment has greatly diminished the number of cases in which it becomes necessary to have recourse to these measures.

Intubation consists in introducing through the mouth into the larynx a tube which allows the patient to breathe freely during the period while the membrane is becoming separated and thrown off.  This is best done with the apparatus of O’Dwyer; but when this instrument is not available, a simple gum-elastic catheter with a terminal opening (as suggested by Macewen and Annandale) may be employed.

When intubation is impracticable, the operation of tracheotomy is called for if the patient’s life is endangered by embarrassment of respiration.  Unless the patient is in hospital with skilled assistance available, tracheotomy is the safer of the two procedures.

TETANUS

Tetanus is a disease resulting from infection of a wound by a specific micro-organism, the bacillus tetani, and characterised by increased reflex excitability, hypertonus, and spasm of one or more groups of voluntary muscles.

Etiology and Morbid Anatomy.—­The tetanus bacillus, which is a perfect anaerobe, is widely distributed in nature and can be isolated from garden earth, dung-heaps, and stable refuse.  It is a slender rod-shaped bacillus, with a single large spore at one end giving it the shape of a drum-stick (Fig. 26).  The spores, which are the active agents in producing tetanus, are highly resistant to chemical agents, retain their vitality in a dry condition, and even survive boiling for five minutes.

The organism does not readily establish itself in the human body, and seems to flourish best when it finds a nidus in necrotic tissue and is accompanied by aerobic organisms, which, by using up the oxygen in the tissues, provide for it a suitable environment.  The presence of a foreign body in the wound seems to favour its action.  The infection is for all practical purposes a local one, the symptoms of the disease being due to the toxins produced in the wound of infection acting upon the central nervous system.

The toxin acts principally on the nerve centres in the spinal medulla, to which it travels from the focus of infection by way of the nerve fibres supplying the voluntary muscles.  Its first effect on the motor ganglia of the cord is to render them hypersensitive, so that they are excited by mild stimuli, which under ordinary conditions would produce no reaction.  As the toxin accumulates the reflex arc is affected, with the result that when a stimulus reaches the ganglia a motor discharge takes place, which spreads by ascending and descending collaterals to the reflex apparatus of the whole cord.  As the toxin spreads it causes both motor hyper-tonus and hyper-excitability, which accounts for the tonic contraction and the clonic spasms characteristic of tetanus.