Phonometry we have found of but little value in the diagnosis of pleurisy.
COURSE AND DURATION. Acute pleurisy is essentially a unilateral disease. It does not pursue a regularly-defined course, nor have we any critical stages, as in pneumonia. In mild cases of acute primary pleuritis the disease advances slowly and recovery is tardy. The febrile movement may be four or five days in reaching its height. It remains at this point for several days—from four to seven days; in rare instances as long as ten days.
The effusion sometimes comes on very rapidly, but ordinarily is one or two days in forming. When it appears it may be divided into (1) the stage of progress, (2) stationary period, and (3) resolution. For the examination of both of these we must employ percussion, and mensuration by means of the cyrtometer, which give us exact results. Woillez in a large number of observations found that the first period lasted from eleven to twenty-four days, most frequently from fifteen to twenty days. The stationary period he found varied from twenty-four hours to several days. Frequently the reabsorption commences suddenly without any interval. Resolution is initiated from the eleventh to the twenty-fifth day, and lasts over fifteen days.
As the effusion advances the acute symptoms—rapid pulse, the elevated temperature, acute pain, and superficial dyspnoea—are materially lessened. If, however, the effusion be very great, we shall have at first painful dyspnoea, especially when the patient makes unusual exertions. This dyspnoea is ordinarily in proportion to the amount of the effusion. If there is much displacement of heart or distortion of larger blood-vessels, there is imminent danger to life. After the first few days we are often surprised at the tolerance of the whole system of the excessive amount of fluid. Absorption, after the effusion has been thrown out, is at first rapid, then it occurs more gradually; part of the liquid portion disappears, and the fibrinous portion undergoes fatty degeneration previous to absorption. The physical signs of flatness, vocal fremitus, together with the return of the displaced organs, the heart, liver, and diaphragm, to their normal positions, give us accurate means of judging of the progress toward cure. The general health shows unmistakable signs of improvement. The appetite is better, as are also the color and strength. If the effusion remains undiminished in quantity, or if it becomes purulent in character, the general appearance will show evidences of weakness and lowered vitality.
The average duration of acute primary pleurisies varies, when the effusion has not reached any considerable height, from two to four weeks. It may continue thirty or thirty-eight days—minimum duration twenty days. The absorption requires many weeks if the effusion is large or if it becomes chronic. Two months may elapse before the fluid entirely disappears. In some cases it continues, unless thoracentesis be performed, for many months. We have given the symptoms manifested when there is any renewal of the inflammatory process. In pleuritis acutissimus death may occur in ten days or two weeks from syncope, or from thrombosis caused by pressure upon the large venous trunks and consequent twisting, especially of the ascending cava, where it perforates the central tendon of the diaphragm to reach the pericardium, or by torsion of the aorta. When the effusion remains for a long time, the lung may be permanently prevented from expanding by pleuritic thickenings resulting from inflammatory products. In acute primary pleurisy the tendency is toward resolution. Louis went so far as to state that pleurisies never caused death. Trousseau, Lacaze, and others give cases where sudden deaths were produced by the quantity of fluid pressing upon the heart and blood-vessels. In subacute pleurisy (latent pleurisy of the older writers) the course of the disease is so gradual, so unattended by pain or even discomfort to the patient, that he goes perhaps weeks with considerable fluid in the cavity without being aware of it. He has probably been able to continue his occupation without intermission. It is only when he begins to feel weak and to lose flesh, and finds that his respiratory force is impaired, that he consults a physician. The rational symptoms scarcely point to pleurisy, but the physical signs of the presence of fluid are very distinctive. In this form the effusion is ordinarily greater in quantity than in the acute variety, and unless some of the fluid be taken away by aspiration, absorption is very sluggish. In these cases, if the fluid remains long in the cavity, the lung may become permanently disabled by the long continuance of the compression.
In chronic pleurisy the effusions from the acute or subacute pleurisies remain unabsorbed. They ordinarily are purulent in character, but sometimes they remain sero-fibrinous many months. Purulent pleurisies may be primary as well as secondary. (See [Purulent Pleurisy].)
TERMINATIONS.—Pleurisy of a fibro-serous nature terminates in (1) convalescence, (2) becomes chronic, or (3) ends fatally. Among those who are cured there are some instances where the disease is of short duration and the recovery prompt and complete. With others the disease itself is of a severer type and lasts longer. If the attack of pleurisy be secondary to another disease, especially if the latter be of a nature to profoundly affect the nutrition, convalescence is very tedious.
Acute pleurisies which are primary but rarely become chronic, but when secondary they frequently are chronic from the beginning. Heyfelder states that chronic pleurisies are three times more frequent on the left side than on the right side.
Trousseau, Bowditch, Lacaze, Behier, and others have reported sudden and unexpected deaths in cases of fibro-serous pleurisies. Not only has this resulted in cases where the fluid was excessive in quantity, but also in cases where the amount was moderate. Wilson Fox (Brit. Med. Journ., Dec., 1877) gathered from medical literature between 50 and 60 sudden deaths from effusions of all kinds. Syncope has been the usually assigned cause of death. Négrié45 collected 12 cases of unexpected deaths from pleurisy, and there were but 2 of them where syncope could be assigned as the cause of the fatal termination. Of the remaining 10 cases, 3 were caused by what is invariably a grave complication, pericarditis, and 7 by clots formed in the heart or pulmonary artery. In the cases where pericarditis existed the deaths occurred as early as the eleventh or twelfth day. In the other cases death occurred as late as from the twentieth to the forty-fifth day. Woillez46 reports 2 cases where death was produced by supervening congestion of healthy lung.
45 Thèse de Paris, 1864.