Laryngitis, or inflammation of the larynx, although by no means a common disorder in the horse, is nevertheless of serious import when it assumes a severe or acute character. In some instances it proves rapidly fatal, as the result of asphyxia or suffocation following upon swelling of the inflamed membrane and consequent narrowing of the breathing aperture. In others it runs a less acute course, and when the disease subsides leaves behind a more or less lingering irritation, attended with chronic cough, and maybe difficulty of breathing.
Laryngitis is more especially seen in stabled animals, and frequently results from exposure to cold and wet after severe exertion, or from sudden changes of temperature in animals occupying hot, badly-ventilated stables. It may also arise out of a common cold, or may appear in the course of an attack of influenza, or strangles, or as the result of the specific poison of glanders, or purpura hemorrhagica. Operations on the larynx for roaring are sometimes followed by it, and we have known it to be induced by the lodgment of foreign substances in the laryngeal cavity. Air charged with irritating vapours is also capable of exciting laryngitis in susceptible subjects.
The symptoms of the disease will vary with the severity of the attack. When it arises out of cold, it is commonly preceded by the ordinary symptoms of that ailment. Usually its onset is marked by general indications of illness, evinced by slight dulness, impaired appetite, increase in the body temperature, quickened pulse, and maybe more or less soreness of the throat. Where no such premonitory symptoms appear the disease is ushered in by a severe and painful cough, which comes on in paroxysms. In character the cough is harsh and coarse, and the painful nature of the act is denoted by the effort which the patient appears to make to suppress it, and the restlessness and excitement it induces. Pressure on the throat gives rise to pain, and its soreness is further shown by difficulty in swallowing, the food being altogether refused, or dropped from the mouth after partial mastication. The nose is protruded, the breathing is much interrupted, each act of inspiration being prolonged and laboured, and attended by a coarse, hissing, wheezing, or roaring sound, sometimes loud enough to be heard at a considerable distance. Intervals of relief occur now and again, when the symptoms of distress subside and the breathing becomes less noisy. As the disease progresses the face wears an anxious expression. The membrane of the eye and nose is of a dark-red or livid hue - denoting imperfect aeration of the blood, which leads the animal to seek for air and turn to the door whenever it is opened. The pulse is quick, full, and firm, and the legs are cold. In the paroxysms of threatened suffocation the animal paws the ground with the fore-feet, shakes the head violently, and breaks out into patchy sweats.
In the treatment of laryngitis it is of the first importance that the patient be provided with a thoroughly clean stable, and that the air be kept free from contamination with the products of decomposition and irritating substances, both solid and gaseous. Nothing tends so much to aggravate the disease as an atmosphere charged with ammonia and other products of putrefaction. It is equally important to keep clown the dust of the stable, which, in passing over the larynx, serves to provoke coughing and add to the breathing trouble. Ventilation should be free, but it is at the same time desirable that the temperature of the stable should not be allowed to fall beyond 55°, or, better still, maintained at 60°, and it is to the advantage of the patient if the air be kept moist. This may be done by introducing pails of boiling water into the stable, from which warm vapour will be given off.
These provisions having been carried out, the surface warmth is to be maintained by ample clothing. The food should be warm, soft, and succulent, and given in small quantities, and often. Bran scalded with hot linseed-tea and mixed with boiled carrots or roots, and given while warm, is the most suitable diet. As a change a few creed oats may be added, or a little boiled oatmeal. Or the patient may be allowed to pick a little scalded hay from a pail while it is still hot. With regard to medicines, it should be borne in mind that where difficulty of swallowing exists the forcible administration of draughts and balls must not be attempted. Small quantities of an electuary, composed of belladonna, chlorate of potash, and treacle may be inserted into the mouth on a stick every three or four hours, when the animal will suck it in. In the act of swallowing it will be conveyed to the throat, and there exercise its soothing influence on the inflamed part. Considerable relief will be afforded by causing the animal to inhale warm vapour from scalded bran contained in a nose-bag. Outwardly, hot cloths, or a linseed-meal and bran poultice, should be applied to the throat, or mustard may be employed instead, or a weak cantharides blister. When, as sometimes occurs, the breathing becomes difficult and attended with a loud roaring noise, the operation of tracheotomy should be promptly performed. This consists in cutting a hole into the windpipe, through which the patient is made to breathe by means of a tube inserted into it (fig. 206). Instant relief follows the operation, and on the subsidence of the disease the tube is removed and the wound allowed to heal. Tracheotomy should not be attempted by any but a qualified veterinary surgeon. Where, as usually occurs in severe attacks, solid food is altogether refused, the strength must be upheld by a liberal supply of eggs and milk, or even beef-tea in linseed or oatmeal gruel. If prostration and weakness are marked, a little spirits of wine may be added to the gruel twice or thrice a day.
Acute attacks of laryngitis not unfrequently leave behind chronic changes in the mucous membrane. It may, for instance, become thickened and irritable, in which case the breathing will be interfered with and a troublesome cough remain for a longer or shorter period. Ulceration of the larynx, beginning in the glands of the mucous membrane, paralysis of the muscles of the organ, ending in roaring, and, lastly, small tumours, are also consequences of this disease.
A course of iodide of potassium and mineral tonics should always be resorted to after the acute symptoms have subsided, in anticipation of one or the other of the changes noted, and an iodine blister to the throat, repeated two or three times at suitable intervals, will also assist in reestablishing a healthy condition in the diseased organ.
Fig. 206. - Tracheotomy Tube inserted in the Windpipe.