PERICARDITIS, or inflammation of the pericardium (q.v.), is a disease of frequent occurrence; the result of a very large number of post-mortem examinations being to show that about 1 in 23 of all who die at an adult age exhibits traces of recent or old attacks of this-disorder.
For reasons which will be obvious when we come to speak of the physical signs of this disease, we shall commence with a notice of the anatomical changes which take place in the inflamed membrane. Very soon after symptoms of pericarditis begin to show themselves there is an abnormal dryness of the serous membrane, which is speedily followed by an increased secretion of fluid. The secreted fluid is sometimes almost entirely fibrinous, in which case it coagulates, and gives rise to adhesions botween the heart and the pericardium; or it may consist almost entirely of serum, which remains liquid; or it may be, and it most frequently is, a mixture of the two. When there is a large amount of liquid effusion (as, for instance, a third of a pint or more) which is not re-absorbed, death, usually takes place in the course of a few days, in consequence of the interference of the fluid with the heart's actions; but when there is not much liquid effusion, or when the liquid part is absorbed, the pericardium becomes more or less adherent, and apparent recovery usually takes place.
In the eases that prove fatal when fibrinous fluid has been effused, but has not coagu lated to such an extent as to cause complete adhesion of the heart to the pericardium, the partially coagulated fibrin (or lymph, as the older authors styled it) is seen to he of a yellowish-white color, and to occur in a rugged, shaggy, or cellular form. Laennec compared the surface on which the-lymph is deposited to that which would be produced by suddenly separating two flat pieces of wood between which a thin layer of butter had been compressed. Dr. Watson regards the appearance as more like the rough side of pieces of uncooked tripe than anything else; while others have compared it to lace-work, cut sponge, a honey-comb, a congeries of earth-worms, etc. When the patient dies at a more advanced stage of the disease—viz., soon after the whole of the membrane has become adherent—incipient blood-vessels, in the form of red points and branching linea, are seen, indicating that organization is commencing in the deposit, which, if death had not ensued would have been finally converted into cellular or areolar tissue, and have occasioned the complete obliteration of the pericardial cayity.
The symptoms of pericarditis are pain in the situation of the heart, increased by a full inspiration, by pressure upon or between the ribs in the cardiac region, and especially by pressure upwards against the diaphragm by thrusting the fingers beneath the cartil ages of the false ribs; palpitations; a dry cough and hurried respiration; discomfort or pain on lying on the left side; restlessness; great anxiety of countenance; and sometimes delirium. The pulse usually beats from 110 to 120 in a minute, and is sometimes inter mittent; and febrile symptoms are always present. These symptoms are seldom collec
tively present in any individual case, and until the time of Louis the 'diagnosis of this disease was uncertain and obscure. The physical signs, dependent on the anatomical changes which have been described, are, however, generally so distinct that by their aid the disease can be readily detected. They are three in number. 1. In consequence of irritation propagated to the muscular tissue of the heart at the commencement of the inflammation of its investing membrane, the ventricles contract with increased force, rendering the sounds of the heart-louder and its impulse stronger than in health, or than in the more advanced stages of the disease. 2. When much fluid is effused into the peri cardium, dullness on percursion is always observable to a greater degree than in health. This sign, which is very characteristic, is seldom perceived till the disease has continued for two or three days. In relation to this increased dullness, we must premise that in the healthy condition of the heart and lungs there is an irregular roundish space with a diameter of somewhat less than 2 in., extending from the sternum (or breast bone) between the level of the fourth and fifth ribs towards the left nipple, in which a por tion of the surface of the heart is not overlapped by the lungs, but lies in contact with the walls of the chest. This space should normally be dull on percussion. In pericar ditis the extent of the dullness beyond the normal limit indicates the amount of effusion. In extreme cases the dullness may extend over a space whose diameter is 7 in. or more. Simultaneous with the increased dullness, there is a diminution of the heart's sounds in consequence of the intervening fluid, and the impulse is often scarcely perceptible. 3. The rubbing of the inflamed and roughened surfaces upon each other gives rise to a sound which is commonly called the friction sound, but which has received various names. Thus Dr. Watson calls it a to-and-fro sound, and observes regarding its varia tions that, " like all the other morbid sounds heard within the chest, it is capable of much variety in tone and degree Sometimes it very closely resembles the noise made by a saw in cutting through a board; sometimes it is more like that occasioned by the action of a file or of a rasp; but its essential character is that of alternate rubbing; it is a to-and-fro sound." This sound is heard early in the disease, before the surfaces of the pericardium are separated by the effusion of fluid; and it is due either to the dryness of the membrane, or to its roughness from the deposition of lymph. When the contiguous surfaces arc either separated by fluid, or become adherent, the sound Thsappears; but when it has been last from the first of these causes, it reappears after the fluid has been so far absorbed as to permit the surfaces again to come in contact. But here, again. its duration is brief, for the surfaces soon become adherent and cease to rub upon each other.