PERICARDITIS.
Definition. Frequency in different genera. Causes, rheumatic, traumatism, extension from pleurisy. Unwholesome buildings and localities, debility. Symptoms, chill, reaction, pleuritic symptoms, hyperthermia, tenderness behind left elbow only, friction sound synchronous with heart beat, later it is lost and heart sounds are muffled, increased area of dulness on percussion, oppressed breathing, venous pulse, patient statant, little fever in chronic cases. Traumatism from the stomach, digestive disorder, grunting, dropsy under the sternum with little fever at first. Lesions, as in pleurisy, obliteration of pericardial sac. In traumatism from stomach the foreign body is formed in the cardiac end of a band of lymph extending to the reticulum. Treatment, in chill, after reaction, medicinal measures as in pleurisy, local applications to the region of the heart. Paracentesis, insertion of needle, antiseptic precautions. Chronic pericarditis in oxen.
Definition. Inflammation of the strong fibro-serous sac in which the heart is contained and which is reflected on the muscular substance of that organ so as to form its external covering.
This is the most common inflammatory disease of the heart and has been met with more frequently in horses and cattle than in the smaller quadrupeds.
Causes. It frequently coincides with or follows other diseases such as influenza, pleuro-pneumonia and above all rheumatism. In cattle and goats wounds from sharp pointed bodies, (needles, pins, nails, etc.), which have been swallowed with the food and have passed through the walls of the second stomach, the diaphragm and pleura to the heart constitute a frequent cause in cattle. The pericardium has been punctured by a fractured rib and has been implicated in inflammation attendant on an abscess or other lesion in the walls of the chest. Besides these the general influences which cause uncomplicated attacks of the disease are the same as those producing pleurisy, peritonitis, rheumatism and inflammation of serous membranes generally. These are sudden changes from heat to cold, cold winds, cold draughts, drenching, chilling rains in animals already overheated and exhausted, or prolonged exposure in severe weather, in low states of the system. Leblanc justly remarks that “with the morbid influences which appear specific, there often coincide intemperate seasons, badly arranged buildings, a want of sufficient attention to the conditions of health, and in the case of herbivora, wet, cold, and badly exposed pastures.” In other words whatever deteriorates the health and vitality predisposes.
Symptoms. These are less characteristic than in man owing to the smaller portion of the heart exposed, but they are usually marked enough to permit a recognition of the disease. Acute form. The affection is ushered in by chill, general fever, hyperthermia, (103° to 104°), staring coat, hot, dry mouth, dilated nostrils, excited, difficult breathing, double lifting of the flank with each expiration, the existence of a prominent ridge from the lower end of the last ribs along the flank to the outer angle of the hip bone, as in pleurisy, pinched, anxious expression of countenance, fixed eyes, accelerated, full, hard and often wiry pulse, and tenderness when the ribs behind the left elbow are pinched or struck. The same tenderness is noticed particularly in the ox and smaller quadrupeds when pressure or compression is made beneath the breast bone. Auscultation over the lower ends of the fifth and sixth ribs and their cartilages detects a friction or rubbing sound in the early stages and until liquid has been thrown out into the pericardial sac. This sound may be at first the finest possible creaking, afterward increasing to a distinct rubbing, is synchronous with the beat of the heart, and usually with the first sound. It is distinguished from the friction sound of pleurisy in occurring rythmically with the sounds of the heart and not with those of breathing, and from sounds produced in the interior of the heart by its absence when auscultation is made over the carotid or other large artery. This friction sound is lost when serous effusion takes place into the pericardium, but reappears when the liquid is absorbed in the process of recovery. Until effusion takes place the impulse of the heart is strong, often irregular, in force, and sometimes accompanied by a purring tremor or, according to Leblanc, a metallic tinkle.
When effusion has taken place the pulse is weaker and softer, irregular or intermittent, the impulse of the heart is weaker, the friction sound is lost, and the area of dulness corresponding to the heart is increased. Percussion shows it to extend higher than three inches above the breast bone in the horse and more than two or two and a half inches transversely. It is distinguished from the effusion of pleurisy in this, that the dulness is confined to the anterior part of the chest, having the outline of an inverted cone, and does not extend backward along a horizontal line, and, in solipedes, in not showing equally on both sides. In the smaller animals it may be distinguished by not always occupying the dependent part of the chest when the animal is placed in different positions. As the effusion increases, the heart’s sounds, previously strong, become first muffled, then more and more distant until they may become altogether imperceptible. The difficulty and oppression of the breathing increases, the nose is protruded, the eyes more rigidly fixed, and the face more haggard; a venous pulse, apparently due to the compression of the heart and large veins by the fluid, is seen in the lower ends of the jugulars, and the animal obstinately stands as indeed the solipeds do all through the disease. At this advanced stage dropsies of the limbs, sheath, and other dependent parts of the body are frequent.
A painful cough is sometimes though by no means invariably present throughout the disease. Emaciation takes place rapidly and in the more acute cases death ensues in five to eight days. A fatal issue may be delayed until after three weeks or the affection may merge into a chronic form.
Chronic Pericarditis is sometimes seen in the ox without any preceding acute attack. This is manifested by the local symptoms without the accompanying acute fever. Along with a slight fever, there is the oppressed breathing aggravated by exertion, the weak irregular or intermittent pulse, the weak or distant heart sounds, the absence of respiratory sounds and the dullness on percussion over a space represented by an inverted cone at the anterior part of the chest on each side, the venous pulse in the neck and the general tendency to dropsy.
If the pericarditis has been the result of sharp pointed metallic bodies swallowed and afterwards making their way to the heart, it is sometimes preceded by eructations, tympany, difficulty in swallowing or in rumination, and by dropsy under the sternum, but more frequently the heart symptoms are the first to be noticed. It is not attended by the high fever of other pericarditis.
Post Mortem Appearances. These do not differ materially from those of pleurisy, to which accordingly the reader is referred. The effusions and false membranes are of course localized in the sac of the pericardium. A frequent termination is a permanent adhesion of the pericardium throughout more or less of its extent to the surface of the heart. In cases of death the serous effusion is commonly colored with blood though mostly from a post mortem infiltration of blood from the congested lungs. The effusion has been known to measure fifteen litres in the horse. It may be purulent or combined with fœtid gases, particularly in traumatic cases. After mild attacks white patches (milk spots) are often left extending, it may be only through the pericardium and in other cases reaching into the muscular substance. At a less advanced stage the false membranes are yellow, with a rough or villous surface, they may be softened from fatty degeneration or they may be more or less completely calcified.
When the cause has been perforation by a metallic body, it will be found surrounded by exudate enveloping a canal or band extending to the diaphragm or stomach.
Treatment. Pericarditis often proves fatal but it is by no means invariably so in uncomplicated cases. There is especial danger when serous effusion is excessive, when it occurs in a weak and debilitated subject, or when it is complicated by pleurisy, influenza or rheumatism. The preliminary chill may be met by the measures advised for the rigor of pleurisy, but if the malady is developed other treatment is required. The medication is still essentially as for pleurisy, only the primary disease (rheumatism, influenza, pneumonia) must be specially attended to when such is present. Acute pain may be met by carefully graduated doses of opium or aconite and by the moist jacket or fomentations. Some employ icebags to soothe at once inflammation and pain and in the absence of rheumatism these may be resorted to. In the small animals leeches may be applied over the cardiac region. Dry cupping is a good alternative applicable to all.
An active purgative is demanded unless the affection is attended by a low type of fever or has occurred during the course of an epizootic disease (Horse 5 to 7 drachms aloes, cow 1 to 2 lbs. Epsom Salts, dog 1 oz. castor oil). After the walls of the chest have been well fomented they may be enveloped in a large mustard poultice which must be continued until a considerable effusion has taken place beneath the skin. To moderate and control the heart’s action give digitalis (horse and ox ½ drachm, dog 2 to 4 grains) four times a day. After the purgative has acted an ounce of nitrate or acetate of potass may be given daily to the larger quadrupeds (1½ drachms to sheep and pigs, and 20 grains to dogs) in the drinking water. These agents together with the digitalis must be pushed to the largest doses when the effusion has taken place abundantly and when it threatens to dangerously interfere with the heart’s action. Pilocarpin is a dernier resort, to be used with caution. In similar circumstances, ointment or tincture of iodine should be freely applied over the chest in the region of the heart. Mustard and other vesicants repeatedly applied often greatly hasten the reabsorption of the liquids.
From the first the animal must be warmly clothed and every means employed to obtain free circulation and warmth on the surface. The legs must be well rubbed and wound in warm flannel bandages, or this failing, may have mustard freely applied to them. Warm injections must be at the same time thrown into the rectum and will benefit by soliciting the action of the bowels as well as in raising the temperature of the surface generally. The food allowed should be warm mashes of wheat bran, boiled linseed and similar agents in small quantities.
If the amount of effusion threatens a fatal result, it may be drawn off by a cannula and trochar introduced between the cartilages of the fifth and sixth ribs, by a valvular wound and with antiseptic precaution (see hydrothorax), care being taken to avoid puncturing the heart itself.
The trochar or aspirator needle should be pushed in a direction upward and inward until resistance ceases or it is felt that the heart has been touched. A caoutchouc tube may now be attached to it and allowed to depend twelve or eighteen inches, and its lower end should be plunged in a weak solution of boric acid or other antiseptic. This avoids the entrance of air and insures against the introduction of ærial bacteria.
When the vital powers are being exhausted stimulants must be given to support the animal, combined with iodide of potassium. (See advice concerning the allied condition in Hydrothorax).
In the chronic pericarditis of oxen the fatality is greater. Treatment consists mainly in counterirritants and powerful diuretics employed in doses determined by the strength of the animal, and combined with stimulants and tonics as in the advanced stages of the acute disease.
In complicated forms of pericarditis attention must be given mainly to the constitutional affection, thus in influenza a stimulating and supporting treatment is demanded, and in rheumatism colchicum, acetate of potass, salicylate of soda, salol and similar agents must be freely administered, though not to the exclusion of counterirritants to the region of the heart, and other measures demanded by the heart diseases.