Cyanosis is a symptom which should cause serious alarm, for it shows that the effusion is so great as to interfere very materially with the due arterialization of the blood. When the cyanosis is accompanied by pallor, coming on suddenly in the course of a pleurisy, we may infer with considerable probability that there is a hemorrhagic exudation. But if the paleness comes on slowly during weeks or months, it may also be dependent on a simple sero-fibrinous effusion (Fraentzel). Protracted cases of effusion, especially if purulent, are associated with emaciation and loss of strength. There may exist more or less oedema of the lower extremities and of parts of the body where the patient lies down, as we have in the chronic diseases of the chest. When this oedema is limited to the affected side of the chest, whether it be extensively developed and spread over the entire half of the chest or confined to certain spots, it almost invariably justifies the diagnosis that the effusion is purulent. The effusion may, however, be purulent without the presence of this localized oedema. Occasionally, cases are met with of effusion in the left pleura where there are visible and palpable systolic pulsations in the intercostal spaces arising from the impulse of the heart or of the larger blood-vessels passing through the fluid.
Physical Signs.—Perhaps in no other disease of the chest are physical signs so important for purposes of diagnosis as they are in pleurisy. Even at the very beginning of the attack they give us valuable information. In later stages, when the effusion is in the pleural sac, they furnish, as we shall hereafter show, trustworthy data for diagnosis, prognosis, and also very valuable indications for treatment. There is no other disease of the chest where the physical changes made by the inflammatory process are so pronounced and so accessible to the senses of hearing, sight, and touch. The physical signs are so marked that, almost by themselves, they give us the pathological condition. They have been so carefully studied, and their correlative value insisted upon, that they are readily interpreted. One is often tempted to rely too much upon them to the exclusion of the proper consideration of the general symptoms.
As the physical condition of the pleuræ varies much in the several stages of the disease, the physical signs must necessarily vary accordingly.
At the very beginning of the attack the sensibility of the pleuræ is augmented by the inflammation. Consequently, on inspection, it will be observed that the patient is careful to avoid the pain caused by the inflamed pleuræ rubbing together. He not only tries to avoid using the ordinary muscles (especially the intercostals) for enlarging the capacity of the lower portion of the chest, where the disease is generally found, but he retracts his chest and keeps the pleuritic side almost motionless. The well side has double work to do, and is seen to expand more fully. The patient will frequently press the lower ribs in, on the affected side, with his hand, or he will lie on that side, so as to control the expansion of the chest, or he will lie on the healthy side and bend his body over.
The respiratory movements are marked by an irregular and jerking rhythm, and are quickly made. The pain felt on inspiration is of a catching or stabbing character, and produces dyspnoea, the subject struggling for air. The diaphragm is held as fixed as possible, so as to prevent the movement of the inflamed surfaces over each other. The patient restrains as far as possible the respiratory movements, especially those of expansion and retraction. This is the condition not only at the initiation of the disease, but at the next stage, that of effusion. We meet with the same painful respiration also in dry tubercular pleurisy. Mensuration shows that the sound side of the thoracic cavity is slightly enlarged by the extra work it has to perform in the first stage. The elevation movement is noticed to be restrained when the effusion has increased to the extent of overcoming the retractility of the lung, for the diaphragm is no longer drawn up by the lung, and the effusion rises and separates the parietal and pulmonary pleuræ. The diaphragm bags from the quantity of fluid, and contracts but feebly. This condition forces the liver and the spleen down in the abdominal cavity. Gradually the jerking rhythm ceases as the effusion advances, and the characteristic stitch in the side disappears. If the effusion increases until it reaches as high as the second rib, the respiratory movements are scarcely perceptible to the eye. When it reaches its maximum, the clavicle, they appear to be arrested, but the vertical diameter is slightly altered by the action of the intercostal muscles as they endeavor to elevate the ribs, and of the diaphragm as it feebly contracts and relaxes. The pleural cavity, which in health is lubricated by about two drachms of moist serous secretion, is frequently filled to the extent of seventy, eighty, or more—even to one hundred and twenty—ounces. We cannot wonder that it should be changed in shape and diameter. All available space is filled with the fluid, and yet the serous membranes continue to throw out the secretions. The lung must lose in size by its retractile force, and when that is overcome the fluid must press in all directions. The fluid gradually rises from the surface of the pleura over the diaphragm, and the lung, by negative pressure, draws it and the fluid upward. As long as the diaphragm is arched, although the lung recedes before the effusion, it is not really compressed. When, however, the diaphragm yields and falls from the large quantity of fluid, then the fluid conquers the lung. Ordinarily, the fluid, when in excessive quantities, presses upon the lung and the bronchi until it forcibly expels the air; the lung is compressed against the vertebral column, occupying a very small space corresponding to the surface under the scapula, often not larger than from three and a half to four inches square. Inspection shows that the spaces between the ribs become flattened out, that the ribs are more widely separated, and that the spaces themselves frequently bulge. The first observable indication of great distension of the pleural cavity, sufficient to cause intra-thoracic pressure, is the depression of the diaphragm, and next the flattening of the spaces between the ribs. This last is followed by increased pressure, which causes more general and marked enlargement. "This levelling of the intercostal spaces is due partly to paralysis of the intercostal muscles from serous inflammatory infiltration, and partly to the limited range of movement now possessed by the lung, which is reduced in volume by the effusion, and is no longer in contact with the thoracic parietes" (Guttman). This is especially noticed in children and young persons before the ribs become firm and resisting, the negative pressure exerted by the lung being in part annulled by the presence of the fluid. The diaphragm is notably depressed, and pushes the liver, the spleen, and the stomach below their usual point. So great is this centrifugal force that the heart's impulse may be felt in the epigastrium. The heart, when the effusion is on the left side, is frequently found over to the right of the sternum, and, in extreme cases, even in the right axilla. When the effusion is on the right side, the mediastinum is drawn over with it, and the heart is forced to the left until the apex-beat is perceived as far as one and a half inches to the left of the line drawn through the nipple, or, in some cases, to the left axilla. This rarely occurs unless we have fluid intra-thoracic pressure on the diseased side in addition to lung-traction of the healthy side. Even the costal pleura, projecting above the clavicle, may yield to pressure. Inspection reveals to the observer these striking physical alterations. Hippocrates did not fail to notice them.
1st. Mensuration shows that the semicircular, antero-posterior, and vertical measurements of the side are generally increased. According to Douglass Powell, the total circumference of the chest is always increased in effusion. 2d. Except in children, the bulging of the intercostal spaces does not occur until after the adjacent organs have been displaced by the fluid. When the effusion is large, it becomes evident, by inspection and by pressing the hand over the sides of the chest below the armpits, that there is almost immobility of the diseased side. We insist upon the importance of daily and repeated comparative measurements of the two sides as aids to diagnosis and prognosis in pleurisy. A full inspiration or a prolonged expiration will sometimes show a marked difference by measurement when it is not discovered during ordinary breathing. Woillez's cyrtometer, as perfected by Samuel Gee, is the best instrument for testing the circumference of the chest, and a pair of callipers for the diameter. The cyrtometer tracings give us the altered shape as well as circumference. It is especially valuable in the diagnosis of local empyema from basic pulmonary cavities. Care should be taken not to confound congenital deformities in the shape of the chest, such as the alar, flat or pigeon-breasted, or rachitic, with alterations produced by internal disease. It must also be borne in mind that the semi-circumference of the right side is normally greater by one-quarter to half an inch than that of the left side. By inspection of cases where large effusions have remained for long periods of time slowly absorbing—often, perhaps, not recognized—we discover marked unilateral retraction of the chest-walls, with torsion of the spine and shoulders. The adhesions preventing the lung from expanding, the alveoli become obliterated, and we have, in fact, atelectasis of the lungs. This is particularly the case in children, where the disease prevents the proper development of the side, the healthy side becoming, from supplementary work, more enlarged. Care must be taken not to confound with these the anatomical depressions met with sometimes in the anterior wall of the chest, especially at the lower portion of the sternum. The amplification of the chest takes place, to a greater or less degree, at its lower portion as soon as an appreciable quantity of liquid collects, long before it is possible to have any intra-thoracic pressure. The lung by its elasticity collapses, and the fluid is drawn upward in contact with the lung. The thoracic wall, consequently, has not, at that point, the retractile force of the lung to counteract its excentric resilience. It is not then drawn in in expiration by the lungs, while it is continually being drawn outward in inspiration. The lung-traction of the parietes of the chest is feeble from the diminished size of the lung. The greater the amount of fluid, the less lung-tension; consequently, the greater the enlargement of the chest, as shown by the cyrtometer. If the lung is contracted to its utmost limit (one-third of its size, according to Powell; one-eighth, according to Rokitansky), then there could be no suction force exercised by it upon the parietes of the chest, for, being disabled in its elasticity, it literally has no power. The whole parietes of the chest on the diseased side have nothing to antagonize their elasticity, so it is kept enlarged. In addition, at this stage the fluid of itself presses against the walls of the chest in all directions.
The elastic pulmonary tissue is always, to a certain extent, on the stretch. It is striving to pull asunder the pulmonary from the parietal pleura; but this it cannot do, because the air can have no access to the pleural cavity. The five mm. of mercury elasticity of the lungs can be increased by a distension of the chest from a forcible inspiration to thirty mm. of mercury. Anything which lessens this elasticity of the lungs takes off so much from the force which interferes with the rebound of the thoracic resilience, and consequently increases the circumference of the chest. Such is the case in emphysema, oedema of the lungs, pulmonary congestion, and, curious to relate, at the outset during the pyrexial stage of acute diseases, such as pneumonia, variola, bronchitis. The enlargement of the thoracic circumference is appreciable. It, however, gradually decreases and becomes normal. This yielding of the thoracic walls is attributable to temporary engorgement of the lungs, lessening their retractile force.
At the very commencement immediate results of percussion are negative, but by delicate taps over a pleximeter there is a sound at the margins, owing to the deficient expansion, of impaired resonance and of higher pitch, and the vibrations are less full. There is also a sense of pain, owing to the increased sensibility of the costal pleuræ. As the fibrinous coatings form, the sound becomes less and less full and the normal vibrations of sound are less diffused, more circumscribed, giving to the finger, used as a pleximeter, a sense of resistance from the diminished elasticity of the lung. This is especially the case at the base over the attachment of the diaphragm. As the effusion rises from the base, the sound on percussion becomes flat. The fluid being a non-resonant body, the vibrations of the percussion taps do not extend. The sound is of high pitch, but not resonant. It has been properly designated by Skoda an empty sound, for it conveys to the ear the condition beneath, which is one of perfect airlessness. It is not simply a dull sound or one where there is not the normal resonance, but it is destitute of all resonance: it is absolutely flat. The confusion of dulness with flatness has in the past led to erroneous conclusions as to the line showing the level of the fluid in pleurisy. As high an authority as Woillez, in reference to fluid flatness, speaks of dulness as complete, absolute, or very incomplete sub-dulness! The muscular coverings of the walls of the chest or unusual amount of adipose tissue or pleuritic coatings or bands produce impairment of resonance, and sometimes marked dulness on percussion. But when the percussion wave penetrates to the lungs, there is more or less resonance. When the lung is solid from pneumonia or tubercular deposits, the sound is often very dull, but rarely flat, because it seldom happens that all of the alveoli are filled up, and even when they are the vibrations are communicated to the bronchial tubes which contain air, and in this way there is some resonance. We call particular attention to the importance of these distinctions and to the necessity of light and delicate percussion in order to test the resonance or non-resonance of the thoracic cavities. If the percussion be strong, the vibrations are conveyed by the thoracic walls to the portions where there is no fluid, and thus we have impaired air-resonance, and not flatness. We have frequently seen errors of diagnosis in cases of pleurisy owing to the physician percussing with too much force. To secure accuracy, Garland25 lays down the simple rule of percussing with great care and always in straight lines, and of percussing each line to its terminus before taking up another. Powell26 compares the peculiar flat percussion sound of pleuritic effusion to that elicited on striking against a brick wall. The flatness is characteristic and more marked than the dulness of lung-consolidation. If we are not careful to make the distinction between impaired resonance and non-resonance, we may easily draw erroneous conclusions as to the rise and extent of the fluid in the chest. We have shown elsewhere (Pathological Anatomy of Pleurisy—[Distribution of Fluid]) that, as the fluid collects in the cavity, the lung contracts before it. The border above the level of the liquid contains less air, the capillary circulation is less active, and frequently there is more or less oedema, owing to its being the most dependent portion. These physical conditions impair, to a greater or less extent, the pulmonary resonance. Thus at the base above the fluid we might, on reflection, naturally expect some dulness on percussion, lessening as we recede from the fluid. Several observers have called attention to the impaired resonance over the lowest portion of lung posteriorly when the person is standing. Garland27 termed it the dull triangle. Heitler28 of Vienna observed this same condition in that locality, and likened it to a monk's hood cut longitudinally through the centre and hanging apex down. Rosenbach29 of Breslau noticed that this non-resonant triangle in pleurisy would often clear up on exercise or by breathing; this fact he considered distinctive between pleurisy and pneumonia.
25 Loc. cit.
26 Med. Times and Gazette.