Part 39

“3. I use the trochar after three or four weeks of ineffectual treatment, without any absorption being produced.

“4. In chronic idiopathic hydrothorax, a latent pleurisy with simply physical signs to indicate extensive effusion, but when the rational signs are either very slight or none at all save a general malaise and weakness.”

The use of iodide of potassium and vegetable and mineral tonics must be perseveringly employed and the strength further supported by a generous diet, to secure the animal against the dangers of extreme prostration, of suppuration, or other undesirable conditions of the exuded product.

Among the dangers attending thoracentesis are fainting as a result of shock on the sudden withdrawal of so much liquid, rupture of the false membranes, and even of the enclosed lung tissue or of blood vessels, under the sudden expansion of the partially collapsed lung confined by the investing false membrane, and the introduction of pus or septic germs into the pleural cavity. To obviate the first named dangers tight bands (circingles) around the chest will give support and limit sudden expansion. In case of excess of liquid the withdrawal of one-half or two-thirds at a time will allow opportunity for accommodation. Hæmorrhage may be met by the internal use of chloride, sulphate or nitrate of iron, matico, hamamelis or tannic acid, and a weak solution of boric acid or other antiseptic agent may even be injected in small amount into the pleural cavity.

In obstinate and chronic cases the injection of a weak solution of iodine and iodide of potassium is often of service. In other cases a normal chloride of sodium solution (previously sterilized) may be introduced as soon as a partial evacuation causes uneasiness, and by a succession of such evacuations and injections the residuum liquid may be rendered clear and largely aseptic on a single occasion.

In the smaller animals the selection of the most dependent part for insertion of the trochar is not so essential, as the body may be turned to facilitate the drainage.

On completion of the operation the wound may be again treated antiseptically and coated with aristol or collodion.

PNEUMOTHORAX. AIR OR GAS IN THE PLEURA.

Causes, decomposition of liquid effusion, perforation from a bronchium, the stomach, a thoracic wound. Symptoms, metallic tinkling, splashing, succussion, drum-like resonance, suppressed respiratory murmur, distance of cough sound, distress, anxiety, dyspnœa, bulging intercostal spaces, sometimes a wound. Treatment, closure of wound, calmatives, aspiration of gas. Treatment for pleurisy.

The collection of air or gas in the cavity of the pleura has already been noticed as coexisting with liquid effusion in some cases of advanced pleurisy. It may arise from other causes, among which may be noted: 1. When a mass of pulmonary tubercle connected with a bronchial tube has opened into the pleural sac. 2. When a communication has been established between the pleural cavity and the alimentary canal, as in combined rupture of the stomach and diaphragm, or of the double colon and diaphragm. 3. When a rib is fractured and the broken end penetrates the lung tissue and opens into one or more small bronchial tubes. 4. When a wound has been inflicted penetrating the walls of the chest and forming a valvular orifice through which air is drawn inward during each inspiratory act, but out of which it cannot pass when the thorax collapses.

The amount of gas present may be extremely slight, or in a case such as that from a valvular wound it may cause complete collapse of the lung, filling up the entire half of the thorax and bulging into the opposite half.

The symptoms are often very obscure. If with liquid the metallic tinkling after rising, in small animals the splashing when shaken and the other sounds of auscultation and percussion will point it out as described under pleurisy. In the case of a broken rib the distortion, swelling and tenderness, will lead to suspicion. A penetrating sound will be sufficiently evident, and in the case of tubercle previous cough and ill-health will have been manifest.

The specific signs of uncomplicated pneumothorax are: 1st, A drum-like resonance on percussion over the seat of the gas, usually at the upper part of the chest; 2d, A partially suppressed or distant respiratory murmur over the same area; 3d, A muffled or suppressed sound of the cough; 4th, Sometimes, especially if the gas is abundant, prominence of the chest on that side; 5th, There are also more or less distress and anxiety, difficult breathing, quick, weak, rapid pulse, and other signs of illness.

Some cases of this kind recover spontaneously or with the liquid effusion with which they are associated; in traumatic cases the wound is sometimes sealed up by a pleuritic exudation which here becomes a curative process; while in some examples of valvular wound of the lung or walls of the chest death may ensue in a period varying from a few minutes and upwards to weeks.

Treatment is limited to the prevention of the ingress of air through an external wound where that exists; the employment of opiates and other agents to moderate attendant suffering; to measures calculated to moderate the intensity of resulting pleurisy, and, in cases where there is imminent danger from accumulation of gas, to the puncture of the chest and the careful withdrawal of the gas by aspiration. If necessary sterilized air may be made to replace the aspirated gas.

PYO-PNEUMOTHORAX, EMPYEMA.

Causes, septic cocci entering through wound or blood. Symptoms, those of hydrothorax, with prostration, fœtor, and it may be issue of pus. Treatment by antiseptic injections.

A purulent fluid in the pleural cavity may be found in ordinary pleurisy, but is much more likely to supervene in traumatic forms, in which the pus cocci reach the cavity through the wound of the bronchia, alimentary canal, or chest walls.

The symptoms are essentially those of pneumothorax, with greater prostration, and in certain cases a distinct feverish smell or fœtor of the breath, or the escape of pus through a wound. In treatment the difference from pneumothorax is mainly in the antiseptic character of the injections and the freer employment of stimulants and tonics. Salt, salicylic acid, borax, peroxide of hydrogen, aluminium acetate, or potassium permanganate solutions may be used. Tonics (quinia) and antiseptics (sulphites, salicylates, iron) may be given.

CHRONIC PLEURISY.

Animals liable. Causes, irritation through effusion and exudate acting on susceptible pleura, or by other disease products in lung or pleura. Unhygienic surroundings and management predisposes. Frequent chills in cold water. Symptoms, unthriftiness, easily blown, fatigued, or sweated, cough, paroxysmal under exertion, pallor of mucous membranes becoming congested on slight exertion, difficult breathing when recumbent, percussion and auscultation signs of pleurisy and hydrothorax. Lesions, great liquid effusion, clotting on exposure, with much albumen and cell forms. False membranes partially organized. Treatment, tonic, diuretic, derivative, diet nourishing, counterirritants, paracentesis.

In all domestic animals acute pleurisy may merge into the chronic form, the irritation being maintained by the presence of the residuum liquid and the false membranes and adhesions which interfere with the free dilatation of the chest. The pleura too, having been once inflamed, retains an increased susceptibility to such disturbing conditions. In other cases the affection is symptomatic of other chronic affections, as tuberculosis, glanders, and neoplasms of various kinds. It has been seen especially in old, weak and debilitated subjects, kept in confined, impure stables or habitually exposed to undue cold and damp. Hence dairy cows in unhygienic conditions, and hunting dogs, which plunge in water when heated, are among the most frequent victims.

Symptoms are often obscure. The affected horse may be bright and lively, showing little respiratory disturbance unless under exertion. Yet there is a general appearance of unthriftiness, with erect, dry hair, hidebound, and a small, dry cough. Under work there is hurried breathing, early exhaustion, ready perspiration, and aggravation of the cough which then occurs in paroxysms. Auscultation and percussion give characteristic signs according as there may or may not be false membranes or effusion at particular points. It is usually bilateral in horses, unilateral in other animals.

In cows in addition to the corresponding symptoms, there is pallor of the mucous membranes when at rest, quickly transformed into congestion under exercise, suppression of the milk, and weak heart beats unless when excited. In the advanced condition the animal has difficulty of breathing when recumbent on the sound side and subcutaneous infiltration is felt or seen beneath the sternum or in the limbs. The affected side shows an increased dimension, vertical and longitudinal, of the chest, and the intercostal spaces in their lower part bulge out and fluctuate.

In cows and indolent animals there may be a quiescent condition or very slow progress, but any violent exertion is likely to give a sudden stimulus to the morbid process.

Lesions. The liquid effusion, usually unilateral, except in the horse may amount to 40 quarts in the latter animal, 30 quarts in the ox (Rigot), and 5 to 6 quarts in the dog. Unless there has been a recent sudden accession of inflammation it is of a pale straw color, with, in the dog, a slight rosy tinge. It clots loosely on exposure to the air and contains a large amount of albumen and few cell forms. The false membranes are thick and white at some points and red and vascular at others. In the main they are completely organized. The lung is more or less collapsed and the right heart dilated and attenuated.

Treatment must be in the main tonic, diuretic and derivative. Food must be nourishing, digestible and in liberal amount; diuretics and bitter tonics with digitalis and, (if there is little fever) preparations of iron are to be pushed as far as the strength will allow; and the counterirritants applied to the sides of the chest a number of times in succession. Iodides may be used internally and externally, and paracentesis must be employed unless early improvement is manifested.

PLEURODYNIA.