Inflammation of the serous membrane that invests the lungs and lines the cavity of the chest. It may exist as a distinct disorder or complicate an attack of lung disease. One side only or both may suffer.
Sudden chills, as exposure to cold draughts and cutting winds when the animal is overheated, swimming under like conditions when following hounds, invasion from contiguous structures, as in inflamed lungs. It may also come about by direct injury from external violence to the walls of the chest, or result from morbid growths. As a sequel to other diseases, as influenza and various forms of blood-poisoning, it is not uncommon.
Marked rigors or shivering fits usually usher in the disease, and the temperature of the body shows a considerable rise. The respiration is quick, short, and painful, the animal manifesting acute pain as soon as the lungs are half inflated. Movement, especially turning, is extremely painful, and is demonstrated by a grunt or groan, and the same result follows the application of pressure between the ribs, and also percussion with the knuckles.
The belly marks a peculiarity of inspiration in this disease, which is diagnostic of pleurisy, especially noticeable during the act of expiration, when a ridge appears along the ends of the ribs, extending from the back of the brisket to the flank, which is not present at other times. Auscultation is a valuable aid in the diagnosis of pleurisy; the ear will detect in the early stage a very distinct friction sound as of two roughened surfaces passing over one another. This sound becomes louder and more distinct until the ordinary breathing murmur is overwhelmed in it, or is too weak to be detected. With the progress of the disease, water is effused into the chest when the rubbing or friction sounds cease. If the fluid accumulates it gives rise to various sounds, as the splashing of rain-drops, a subdued tinkling, or the dropping of water. The amount of fluid accumulated is sometimes very great, and it may for some time remain unaltered, but must eventually be either absorbed or by pressing on the lungs cause suffocation and death. Dropsical swellings here and there mark the advance of the disease. The loose tissues under the skin along the breast and belly become infiltrated with fluid, and the sheath becomes enlarged from the same cause. The legs fill more or less, the countenance becomes worn and haggard, the extremities cold, and the belly drawn up at each act of expiration.
The pulse is at first hard and of increased frequency, but as the fluid is effused into the chest it becomes softened and smaller in volume, as well as weak and irregular, and the pain is less severe. The patient persistently stands with protruded head and dilated nostrils, which open and contract in a jerky, spasmodic manner.
Pleurisy is distinguished from other inflammatory chest diseases by greater pain, harder pulse, catchy breathing, and the short occasional cough which the patient endeavours to suppress, as also by the friction sounds and greater sensibility of the chest to external pressure.
In this disease benefit may be expected from counter irritation to the walls of the chest. Here we have but little substance intervening between the skin and inflamed part, and if mustard is beneficial in other inflammatory diseases of the chest it is doubly so in pleuritis. Though bleeding is not so generally practised as formerly, and altogether unsuited to the great majority of cases, there is reason to anticipate beneficial results from a liberal blood-letting at the commencement of the disease, where the patient is in plethoric condition and the attack is of an acute character. But even here it will be of no use, and probably harmful, if delayed to an advanced stage of the attack. In advocating bleeding for pleurisy it is not at any time to be employed on the aged or the weak, nor should it be resorted to where pleurisy follows upon any of the contagious fevers.
Particular attention should be given to the patient's surroundings, which should be comfortable and with every inducement to rest. A roomy, dry, and well-littered box is to be provided, so that no restraint be placed on movement, and ample ventilation should be allowed both night and day. The legs should be kept warm by woollen bandages frequently changed, and the intervals employed in hand-rubbing or wisping them with hay or straw. Warm clothing in the form of rugs and hoods is most essential, with the object of keeping up the circulation on the surface and extremities, and thus aiding in the reduction of inflammation in the affected part. For diet see Catarrh and Pneumonia. The application of moist heat to the sides of the chest is strongly advocated by some authorities, woollen clothes or rugs being dipped in hot water and applied to the chest by means of rollers or bandages, the heat being retained and evaporation prevented as much as possible by a sheet of oiled silk or gutta-percha, or a dry rug.
The medicines to be chosen are those most calculated to reduce ternperature and steady the heart's action in the first instance, and for this purpose alternate doses of aconite and belladonna are in repute. Salines, as the salicylates of soda, and glauber salts, sulphate of magnesia, nitrate of potash, and acetate of ammonia, are recommended as for pneumonia and other inflammatory disorders of the respiratory apparatus. To allay the acute pain which marks the majority of cases at the onset, such anodynes as opium and cannabis indicus may be employed. The latter is perhaps the greatest of pain-killers for horses, nor does it leave the depression which has been noted in the human subject. Subcutaneous injections of morphia may be employed for the same purpose, when objections exist to balls or draughts.
The cases that most often end unfavourably are those which are said to "hang fire". They make very good progress up to a certain point, the temperature falls two or three degrees and then obstinately remains, and the patient goes back; it is then good treatment to repeat the application of mustard to the chest as recommended at first, or a liniment of cantharides may be used, or poultices of linseed-meal, in which a little mustard is mixed, may be applied for a day and a night or until improvement is noted. Where the disease takes the course last indicated, good nourishment with stimulants and tonics will be more likely to do good than those agents recommended for such as follow the more common course.
In convalescence alcoholic stimulants, as gin or whisky, with quinine, gentian, and iodide of iron may prove helpful. Notwithstanding general improvement, a large amount of fluid will sometimes persistently remain in the chest and refuse for a length of time to undergo absorption. Iodide of iron, and those drugs commonly known as diuretics, are best calculated to favour absorption. In some cases, however, it is necessary to remove the fluid from the chest bodily by means of an operation. A liberal diet and very moderate exercise should be allowed when the urgent symptoms have passed, but nothing amounting to work should be imposed for several weeks at least.
Fig. 208. - Tapping the Chest.