SYMPTOMS.—In a large number of cases of purulent pleurisy the general symptoms do not differ materially from those of fibro-serous pleurisies. Sometimes, however, they do. This is according to whether they are acute purulent or chronic purulent pleurisies.

In acute purulent pleurisy the disease commences in the same way as the ordinary acute fibro-serous pleurisy. Indeed, the first effusion is ordinarily serous in appearance, and afterward it becomes purulent. We have the initial chilliness more or less marked, accompanied by the characteristic pain in the side and dry cough, the fever keeping up, even as high as 103° to 104° F.; and soon the signs of an effusion supervene. In a few days, ordinarily, in acute fibro-serous pleurisies, the febrile exacerbation disappears. Graves116 states that the extent of a pleurisy is not augmented after twenty-four hours. In acute purulent pleurisy the fever persists in spite of treatment; the effusion increases, sometimes less rapidly than in the serous variety, but in a continuous manner. If thoracentesis is performed about the eighth or tenth day, we notice that the fluid is opaline and contains a large quantity of pus. After this the fluid is reproduced, and as it forms the fever continues; the skin is hot and dry, the appetite impaired, and sweats appear during the night. In examining carefully the thoracic walls we find oedema of the diseased side. Later on there will probably be oedema of the lower extremities.

116 Clin. Méd., edited by Neligan.

Chronic purulent pleurisy is marked by symptoms somewhat different. It commences in a similar manner to that of acute pleurisy, with fever, but in a few days the fever disappears. In the evenings there may be some febrile action with slight chills. It is remarkable that frequently vast collections of purulent fluid do not give rise to chills. The fluid augments progressively, but sometimes very slowly, and often it appears to remain stationary for a long time. This condition continues sometimes for many months. The patients are pale and feeble, although they may get up and walk until the quantity is increased to such an extent as to impair their breathing capacity. Then the forces of the body by degrees diminish, and the appetite is impaired to a serious extent. The face becomes pale and the lips discolored. From time to time diarrhoea supervenes and oedema of the chest-walls is noticed, and general anasarca comes on without albumen in the urine. If nature does not open an orifice through the parietes of the chest or through the bronchi for the discharge, the patients finally succumb in the last degree of wasting with profuse sweats and fetid colliquative diarrhoea.

PHYSICAL SIGNS.—These, with some modifications, are very similar to those of ordinary sero-fibrinous pleurisy. We have the same dilatation of the chest, but it is more frequently localized. The oedema of the thoracic walls is almost characteristic of the presence of pus in the pleural cavity. We may, however, meet with it in fibro-serous pleurisy and in cachectic subjects on the side of decubitus. Then, again, there are cases of purulent pleurisy where it does not occur. It must be looked for with care, especially at the lateral portion beneath the armpit.

Mensuration and percussion afford especial evidences of purulent pleurisy, and frequently they discover encysted points.

The tubular quality of respiratory sounds is more pronounced, as are also the amphoric characters at the apex, caused by long-continued pressure of the compressed lung around the large bronchi. Ægophony is less frequently heard, the bronchophony is distant and less distinct, and vocal fremitus is more completely abolished. The non-transmission to the ear of the whispered voice through the walls of the chest (Bacelli's sound) in purulent pleurisy is a sign of considerable significance in tracing the transformation from serous fluid into pus. We must, however, bear in mind that when the sero-fibrinous effusion contains fibrinous flocculi, it has the same effect as a purulent fluid in interfering with the passage of the voice. (See article [ACUTE PLEURISY].)

DIFFERENTIAL DIAGNOSIS can be but indifferently reached by considering the points mentioned. An exploratory puncture enables us to decide with certainty as to the nature of the fluid. Without this the diagnosis is often very difficult. In acute purulent pleurisy the diagnosis is most difficult, especially at an early period, because the general symptoms and the local signs resemble closely those of ordinary pleurisy. When, however, the disease is further advanced, and we have the earthy aspect of countenance with oedema of the thoracic walls, we can be nearly positive in our opinion. Moutard-Martin117 speaks of this localized oedema at the level of the fluid as a certain indication of the purulent character of the fluid. But this oedema, as he admits, does not always exist. It is wanting in many cases, and it may be found in cases of sero-fibrinous effusion where the patient has been lying on the side, and in other cases of advanced cachectic disease. Formerly, there were many more errors of diagnosis, which were only discovered at autopsies, but now, thanks to aspiratory punctures, the diagnosis is much more accurate, and indicates to us the rational treatment. In both varieties of purulent pleurisy there is a tendency to discharge by making orifices through the walls of the chest or through the lung. This is nature's mode of spontaneous cure. The most common is the pleuro-bronchial fistula, and the period of the disease at which this accident may occur is very variable. Woillez118 cites a case where it occurred as early as the twenty-eighth day; ordinarily it occurs at a much later period, sometimes as late as the eightieth day. It comes on early in purulent pleurisy. In infants the perforations take place as early as in fifteen or twenty days, and are favorable to the cure in one-half of the cases. Saussier in 29 perforations of this kind counted 15 cures. The symptoms of this accident are easy of recognition. They vary according as the pleuritic effusion is diffused through the whole pleural cavity or is limited, encysted, or interlobular. In the first variety, where we have the physical evidences of the presence of pus, suddenly, during a paroxysm of coughing, the pus is forced up through the bronchi, and the patient in a very short time expectorates a considerable quantity, varying from a few grammes to a liter or more. The quantity thus thrown off depends upon the diameter of the fistula. It may be excessive, as in a case recently observed by the author where suffocation was produced, causing syncope, asphyxia, and death, the flow being so rapid as to fill up the bronchi to such an extent that the patient could not get rid of it. In many cases the pus is brought up more gradually, with successive coughs or with changes of position. Frequently vomiting is produced by the flow from the vomica. After the first instantaneous evacuation of pus (ordinarily continuous, sometimes intermitting) purulent expectoration takes place. The patient may pass hours without any discharge, when suddenly a severe cough brings up a quantity of pus, and again may spend days without further expectoration. Pleuro-bronchial fistulæ may have a valvular character, so that air may or may not be admitted into the pleural sac as the pus is discharged. With or without the formation of pneumothorax there is a tendency to cause putridity of pus. In cases of children, who swallow their expectoration, it often produces a very troublesome diarrhoea. The course of the disease and its prognosis are necessarily altered according to conditions met with. When the air does not penetrate, we observe that the diseased side becomes depressed and the swelling, previously noticed, disappears. The flatness on percussion diminishes or disappears entirely. On auscultation we have coarse râles, sometimes just inside the fistulous orifices, sometimes at a considerable distance. The general symptoms, as well as the physical signs, improve, and the case advances slowly toward cure. Ordinarily, the pus expectorated from the pleura, when free from contact with the air, is odorless, but it is rarely as unpleasant as in bronchial dilatations, unless it is long retained in the cavity, when putrefaction ensues. When the air enters from the bronchi, it frequently acquires a disgusting odor. If the air enters the pleura and takes the place of the pus, the chest remains enlarged. Indeed, it sometimes increases in size to such an extent as to cause suffocation unless the pus and gas are withdrawn. The valve made by the false membrane allowing the air to enter the cavity, but not to escape from it, causes the fluid to accumulate rapidly, and we have pneumothorax to a very painful degree. The diaphragm is pushed down, and, if the disease is on the right side, the liver is forced down, and descends to a level with the umbilicus.

117 Purulent Pleurisy, 1872.

118 Traité Clin. des Mal. Aigues des Organes Resp., 1872.