The collection of gas and fluid may be in such excess as to produce a concavity of the upper surface of the liver, while the organ is forced down into the abdomen. E. Moutard-Martin119 explains this extreme condition by the fact that the fistulous orifice being at the superior portion of the lung, the air having equalized the interior pressure with the exterior pressure, the liquid obeys the laws of gravity, and depresses the diaphragm. The fluid thus does not reach the level of the pulmonary fistula. Under these circumstances the expectoration may cease altogether unless the patient, by change of position, allows it to flow outward through the orifice.
119 Loc. cit.
The physical signs of this condition of pyo-pneumothorax are very marked and characteristic. Above the level of the fluid there is ordinarily a great exaggeration of resonance on percussion, especially at first. At the end of a few days, however, this resonance is sometimes materially modified, and we have obscurity of the percussion vibrations. Percussion, by itself, may lead us into error of diagnosis which the other modes of physical exploration will correct.
On auscultation we hear the amphoric murmur, which is sometimes of great intensity, and at others so feeble and distant as to require great attention on the part of the auscultator. These varieties of the amphoric respiratory sound appear to depend more upon the position of the pleuro-bronchial fistula, and upon the greater or less free circulation of air through the fistula, than upon the extent of the cavity (E. Moutard-Martin). This sound and the amphoric voice are the two principal auscultatory phenomena. There is also the vibrating metallic tinkling produced always in expiration. Although the physical cause may exist, this latter is by no means a constant sign. It may disappear for hours, and even days together, and then be heard for a short time. Sometimes it is only heard when the patient coughs suddenly and violently. When heard it is a very valuable indication of the presence of a pleuro-bronchial fistula. Auscultatory percussion gives us a still more valuable diagnostic phenomenon—the metallic amphoric reverberation—especially if we percuss with a metallic percussor over a metallic pleximeter. The Hippocratian splashing caused by succussion is a more characteristic sign of pyo-pneumothorax than any other we have mentioned. Other signs may fail, and often this is the only sign present. Almost all the symptoms and signs that have been considered characteristic of the presence of pus may coexist with a perfectly limpid sero-fibrinous effusion. We may even have in serous effusions a high, fluctuating temperature, profuse sweats, and quick pulse lasting several weeks. On the other hand, purulent effusions may be associated with symptoms of so mild a character as to lull suspicion. Previous to the application of exploratory punctures for purposes of accurate diagnosis, purulent pleurisies were confounded with the milder disease until so far advanced as to be too late for effective treatment. Now we can without risk discover purulent pleurisies at their very commencement, and before they reach the point of great danger to the subject we can relieve them by thoracentesis, and afterward pursue the treatment for a radical cure.
Limited, circumscribed pleurisies, such as are found at the base of the surface of the diaphragm and in the interlobular fissures, as well as those involving the pleural cavity itself, may empty their contents through the bronchi. As we have shown, the diagnosis of these forms is often very obscure and difficult. The fine capillary exploring-needle is a safe, and often a reliable, means of diagnosis. It may happen that we can only guess at the nature of the disease until, after a protracted cough, there is ejected by the mouth a quantity of pus, and the diagnosis is made clear. We may perhaps discover a point of flatness at the base or about the centre of the lung, but often this flatness is very incomplete, because the collection of pus does not always reach the thoracic wall. It may, indeed, be separated from it by healthy lung-texture. Auscultation may discover coarse râles or even gurgling with cavernous respiration. The voice sometimes has the character of pectoriloquy, at other times of bronchophony: the cavity is rarely large enough or the walls sufficiently firm to give the amphoric tone. Under these circumstances there is neither metallic tinkling nor Hippocratian succussion. The diagnosis of bronchial fistulas caused by encysted pleurisies may be confounded with tubercular cavities or with dilated bronchi. The exact position, however, of the lesion, the rapid manner of the first purulent expectoration, and the nature of the pus expectorated, will enable us always to arrive at an accurate diagnosis. We must remember that in bronchial dilatation the disease is developed by degrees, and the patients do not expectorate suddenly a notable quantity of pus; tubercular caverns are ordinarily at the summit. The mode of expectoration is different, and the matter expectorated does not present the same purulent and homogeneous characters. The general health is very different where encysted pleurisies exist from what it is in patients suffering from tubercular cavities. In the former case it is comparatively good; there are no profuse night-sweats, diarrhoea, etc. Perforation through the thoracic walls may take place at a period more or less remote from the commencement of the disease. The first indication of this result is, ordinarily, a pain over a limited point of one or two of the intercostal spaces, followed, in a few days or a week, by a raised sensitive point on the surface, without change of color of the covering skin. This may remain a long time in an unchanged condition, but generally it increases gradually until it becomes soft and fluctuating, reducible by pressure, but increased in size by efforts to cough or by forcible expectorations. The skin over the raised point becomes thin with a purplish tinge; suddenly, from some effort to cough or unusual exertion requiring suspension of breath, it bursts and gives exit to a quantity of pus far out of proportion to the size of the small tumor. Sometimes there are several such points in the same subject, appearing simultaneously or consecutively, especially if the discharge is not free through the first one. Ordinarily, there is but one which appears on the anterior portion of the chest about the fifth intercostal space or in the intra-mamillary line. These orifices sometimes close and then reopen. Of 18 cases of empyema necessitatis collected by John Marshall,120 1 occurred in the sixth intercostal space and 17 in the fifth, and 6 of his own cases in the fifth, beneath the nipple. This is, as he states, the weak point of the chest, relatively unprotected by the adjacent muscles. The internal intercostal muscle, the weakest portion of the great pectoral, and the thin fascia, are the only coverings at that point. There is valid reason why special bulging and spontaneous perforation should occur there. The spot also corresponds nearly with the middle of the pleural cavity when distended. The fifth intercostal space is wider than those below, and its limiting ribs, held to the sternum, give firmness to its borders—conditions which help the thinness of the walls in determining the place of perforation. In children perforation often takes place in the very wide second intercostal space. The perforation, although it may contract in size, persists and remains a fistulous canal, permitting air to enter and to escape. The fluid rarely becomes fetid unless there is a pleuro-bronchitic fistula or air is otherwise freely admitted. Sometimes when the orifice is oblique, the air does not enter at all. When the purulent effusion escapes through the thoracic walls, the patient experiences at once manifest relief. The respiration becomes better, the fever decreases, the sweats disappear, the appetite improves, and the general condition is decidedly ameliorated. This improvement persists as long as there is free discharge, but if from any cause it ceases, we have a return of serious symptoms. If no air enters, percussion and auscultation show the gradual disappearance of the evidences of disease; but if air enters we have the signs of pyo-pneumothorax, amphoric breathing, metallic and succussion sounds. The diagnosis of parietal openings is comparatively easy: the quantity of pus, its odor, with the physical signs, show its nature. With care this form of pleural opening is distinguishable from a fistula made by caries of the ribs or by vertebral abscesses, and not communicating with the pleura. The existence of a thoracic fistula does not prevent the formation of pleuro-pulmonary fistula, and reciprocally a parietal fistula can be found where the other has been previously formed. The abscesses following purulent pleurisies and empyema have been long recognized. Hippocrates mentioned them as contributing to a favorable prognosis in empyema.
120 London Lancet, March, 1882.
Pulsating empyema is where the lesion is situated in the neighborhood of the heart or of the aorta, which transmit their impulse. They are also sometimes called pulsating tumors, rising and falling with alternate movements of inspiration and expiration (Stokes, Graves, and Aran). These cases strongly simulate aneurisms. According to Fraentzel, the fluid is always purulent. In 1 case reported by him, and in 2 cases seen by Traube, pericarditis with effusion was present. Douglass Powell mentions two well-marked cases of pulsation in the left supra-mammary region where the diagnosis between effusion and aneurism was very difficult, but where paracentesis removed a large quantity of fluid and the signs of pulsation ceased. In these cases there was present neither pus nor pericarditis.
TERMINATIONS.—If allowed to take its natural course, pulsating empyema almost always ends in death from exhaustion or syncope, or by discharging through the lungs or through the intercostal spaces. Formerly, it was oftener fatal than now, but it is still justly considered the gravest form of pleurisy. We have seen that exceptionally it is cured by becoming encysted. It may be cured by spontaneous openings into the lungs, and more rarely by fistulous orifices121 through the walls of the chest. Is it possible for the disease to be cured by the absorption of the pus? The bearing of this inquiry upon the treatment cannot be over-estimated. If absorption can remove the pus, we may safely leave it in the pleural cavity. If the pus cannot be taken up by the absorbent vessels, we ought promptly to make use of radical measures and evacuate it. The literature on this point gives us few reliable cases. Spontaneous cure can rarely be produced by absorption. Douglass Powell122 writes that "the spontaneous disappearance of such effusions is too uncommon to be expected, and the process of reabsorption is one too full of peril to be anticipated with anything but dread. It is indeed an attempt at such absorption that occasions the most characteristic hectic symptoms." Surgical intervention is the rule. The writers previous to the introduction of exploratory punctures speak of cases where purulent pleurisies were diagnosed and the effusions were absorbed. We have shown that the differential diagnosis between serous and purulent effusions is very uncertain when made from the general symptoms and physical signs. Even Trousseau, with all his skill and vast experience, made the mistake of diagnosis, and performed the operation of pleurotomy in a case of serous effusion, and his patient died. There are well-authenticated cases where, after thoracentesis, small quantities of pus left behind have been absorbed, especially in children. That purulent pleurisies have been effectively cured by the pus becoming encapsuled has been demonstrated by autopsies of persons dying from other causes. E. Moutard-Martin reports a case where, after withdrawing with an exploratory trocar a few drops of pus, and thereby establishing the diagnosis of purulent pleurisy, he was unavoidably prevented from opening the chest. Two months afterward he found the effusion had entirely disappeared. He states that this was the only case he had ever seen of a spontaneous cure without evacuation. Douglass Powell has seen one case which has satisfied him as to the possibility of a local empyema becoming absorbed. Wilson Fox reports another similar case. Chronic pleurisies in childhood are almost invariably suppurative, yet Barthez and Rilliet report 7 out of 13 recovered. It must be, and generally is, admitted that cure by pus undergoing retrogressive fatty degeneration, and then being absorbed, is possible, but it rarely occurs. Should the more fluid portion be absorbed, the inspissated pus remaining on the pleural surface may at some future time, upon softening, give rise to secondary tubercular or purulent collections. It is also true that cure is quite often effected by spontaneous evacuation through the lungs and through the walls of the chest. This is especially the case in interlobular effusions and in cases sacculated by adhesions. Such cure is explained by the fact that adhesive inflammation, assisted by the elasticity of the lung on both sides, glues together the walls, isolates the fluid, and prevents air from entering, thus preventing the pus from putrefying.
121 In Andral's 8 cases of bronchial perforation there were only 3 deaths—a mortality less than by artificial opening previous to the application of Listerism.
122 Dis. of the Lungs and Pleura, London, 1878.