A system of practical medicine. By American authors. Vol. 3

by Unknown

Palpation.—The sense of touch gives valuable physical signs in pleurisy. At the commencement, before there is any effusion of fluid, even of fibrinous deposit, we notice by palpation the decreased movement of the walls of the chest, and also the sensitiveness of the walls. When the eye cannot notice modifications of the expansion and elevation movements or movements of the ribs, correct views may be formed by palpation, especially in regard to the amount of local expansion in the upper part of the chest. In the lower part, by inserting a finger in the intercostal space we notice the modification of local expansion, also the convergence of the ribs taking place coincidently with the continuance of the elevation movement. We are thus furnished with additional presumptive proofs of the impermeability of the pulmonary tissue. When fibrinous effusion exists, the hand, early in the disease, recognizes the pleuritic friction or grazing. Later on, palpation perceives the rubbing when the muscles have recovered from their temporary paresis.

As soon as the effusion begins to form we detect a lessening of the delicate vibrations of the voice as communicated to our hands, always guarding ourselves against error by remembering that the normal sound is greater in the infra-clavicular region of the right side, and that it is always weaker in children and women, unless they have shrill, weak voices, in which case it may be entirely absent. It, indeed, requires a certain sonority of voice to be felt through the walls of the chest. When we find that both sides convey the vocal vibrations to our touch, we may be sure there is no effusion of fluid. Errors are often made by applying palpation over too extensive a surface, thus reaching beyond the fluid. It is important to use light, delicate palpation, employing the finger-tips instead of the whole hand, in order to exclude the vibrations from above as we approach the confines of the effusion. This vocal fremitus is entirely lost from the base up to the point to which the fluid reaches, and later on when it separates the two pleural surfaces. This absence of vocal fremitus is one of the most valuable physical signs of pleuritic effusion. It enables us to diagnose it from nearly all cases of lung-consolidation except when caused by malignant disease. When there are considerable pleuritic adhesive bands, they interfere with the complete absence of fremitus; but in children this sign is not so reliable. With them vocal fremitus is often scarcely perceptible in health. In dry tubercular pleurisy palpation gives us the characteristic friction. Palpation detects also the rubbing of the two lymph-covered surfaces after the absorption of the fluid. When there are thick fibrinous bands extending between the parietal and pulmonary pleuræ, there may be a vocal fremitus notwithstanding the presence of a quantity of fluid in the pleural cavity.

Displacement of Adjacent Organs.—The displacement of the heart as a physical sign indicating the presence of fluid in pleurisy is one of great significance. It is indeed a cardinal sign, second only in value to percussion flatness. It is almost invariably met with. Stokes³⁸ stated that it was observed at an early period, and was one of the very first signs of effusion; "that it may exist even before the upper portions of the chest have become dull, and is a circumstance of constant occurrence long before any yielding of the muscular portions of the thoracic walls." The heart is displaced at the very commencement of the effusion, and its dislocation increases pari passu with the effusion. The absence of the displacement, unless it can be explained by some special circumstance which rarely occurs, such as the retention of the pericardium by old adhesions or consolidation of the opposite lung, would negative the diagnosis of unilateral effusion. In this condition there is a marked contrast with the displacement and depression of the diaphragm and the resulting alterations of position of liver, spleen, and stomach. These only occur when the effusion is in great excess—not until from the large quantity of fluid the retractility of the lung is overcome, and it is consequently unable to lift up the fluid and the diaphragm. This altered position of the diaphragm drags the heart downward by means of the ligamentous attachment of the pericardial sac to its tendinous portion. The deviations from the normal positions of the heart in slight effusions can always be noticed if the exact point of the apex-beat is sought for by palpation and listened for with the stethoscope. Careful percussion will show the shifting area of flatness.

³⁸ Dis. of Heart and Aorta, 1854, Dublin.

Powell calls attention to a fallacy with reference to cardiac displacements in the earlier stages of effusion—that, as the base of the lung retracts, the left or the right margin of the heart, as the case may be, becomes uncovered. This may lead to an apparent delay in the displacement of the organ, the more extreme left or right boundary being now within reach of palpation. The axis of the heart is not greatly changed by an ordinary degree of effusion. It becomes a little more vertical, and in extreme cases it may become slightly twisted. Only in rare and extreme cases does the axis of the heart become altered in direction beyond the vertical line. Powell³⁹ found at a post-mortem a heart that had become so twisted as to present itself obliquely edgeways in front. Sibson had previously pointed out this disposition of the heart to turn over and to present its posterior surface forward in cases of effusion.

³⁹ Consumption and Dis. of Lung, London, 1878.

In examining into the cause and significance of the displacement of the heart in pleurisy we find that until within a few years, it was, and indeed very generally now it is, believed that the sole cause was from direct pressure of the fluid actually pushing the heart away from its normal position. Skoda, Traube, Stokes, Powell, and Garland were, we believe, the first authors to show that such was not the case, certainly in moderate effusions. The displacements take place when the amount is very small—too small to exert any positive pressure. It is true that nature places the heart in such a position that it can yield readily to slight forces. It hangs in the pericardial sac, which is suspended by the aorta, and which is bound by ligaments to the body of the third dorsal vertebra. Every change of position of the body causes certain anatomical alterations of the heart's position. Wintrich, Skoda, and Braune think that the heart swings like a pendulum from its base, and that its apex is therefore elevated with every deviation to the right or left. Lebert says the heart is first depressed by the sinking of the diaphragm, and then elevated by being pushed to the right. Fraentzel says that in displacements to the right the heart is simply pushed over, and is never elevated as Wintrich describes it. The mediastinum offers but slight resistance, and is very easily pushed to the right side, where there is no compact organ to resist, and where the cavity is larger; whereas it is with more difficulty pushed to the left, where the heart occupies so large a space.

It has been satisfactorily demonstrated that until the pleura is about two-thirds full of fluid no positive pressure is exercised upon the lungs or heart. According to Rokitansky, the lung cannot be compressed until seven-eighths of the pleural cavity is occupied by fluid. The fluid cannot be drawn off by a canula unless air enters to replace the fluid. Unless the pressure on the fluid from within the cavity is greater than that of the atmosphere we cannot draw off a large quantity: if the pressure balances that of the atmospheric air, only a few drops of fluid are discharged externally, except by forced expirations and coughs. This is the case even when the quantity reached several liters. The feebler the expiratory force the less fluid escaped. Yet the heart is displaced as soon as the effusion appears. The significance of the displacement is that it shows the presence of fluid, but does not show the measure of intra-thoracic pressure (Powell).

Garland's explanation is that the heart, with the sac and its connections, "is placed between two highly elastic bodies (the lungs) which are striving to retract in opposite directions. The heart, therefore, being acted upon on either side by opposing forces, occupies a position where these forces just balance each other; and this is the status of physiological repose in the vertical position of the body. Now, when an effusion is poured into either chest, the lung of that side contracts, and thereby exhausts a certain amount of its retractile energy. The opposing lung, however, still remaining normal, immediately begins to draw the heart toward itself, and the degree of displacement thereby induced will be proportional to the diminution of energy in the compromised lung." Stokes divided displacements of the heart into excentric and concentric. The former he considered due to direct pressure of the fluid, and the latter, when from any cause there was diminution in volume of one lung, the other lung, by its increased volume, forced it over. The concentric displacements, he thought, were generally the result of some chronic disease producing atrophy of lung.

Thus we see that displacements of the heart occur at three distinct periods in the course of pleurisy, and from different causes in each case: (1st) As soon as fluid forms in the pleural sac. At this period the displacement is caused by the presence of the fluid which occupies part of the pleural cavity. The lung by its elasticity retracts. It is, consequently, of less volume and exerts less negative force upon the mediastinum and its contents than the healthy lung. The two lungs having by their equal tractile energy previously kept the heart in situ, the healthy lung draws the mediastinum out of its position in a transverse direction. Necessarily, the displacement of the heart from this cause is in proportion to the amount of fluid effused. This is the most frequent mode of displacement of the heart. It can be said to be almost always present. (2d) When the quantity of fluid is great enough to overcome the retractility of the lung and exert intra-thoracic pressure, it forcibly expels the air from the alveoli of the lung and by direct positive pressure pushes the heart aside. The displacement of the heart in this case can only be produced when the pleural sac is two-thirds or more filled by fluid. When this condition is met with, the displacement is very great, because the heart has been already displaced by lung-traction. Previous to the researches of Garland, Stone, and Powell, this was supposed to be the only manner of explaining the displacement of the heart from pleurisy. (3) Where, as illustrated by Stokes',⁴⁰ Hunt's,⁴¹ and Chew's⁴² cases, the heart is displaced toward the diseased side. This occurs more as a sequel of pleurisy in the course of the absorption of chronic or suppurative pleurisy, where by non-expansion of lung a partial vacuum is produced. The external atmosphere presses in the thoracic walls of the diseased side, and the internal atmospheric pressure from the healthy side is exerted against the mediastinum and presses the heart in that direction. Marked displacements from this cause are rare; slight displacements are more frequent. Cicatrices from healing of large cavities would have this effect. Mere consolidation of lung could not cause it.