PLEURISY, or Pleuritis (Gr. πλεῦρα=ribs), inflammation of the pleura, caused by invasion by certain specific microorganisms. (See Respiratory System: Pathology.) Secondary pleurisies may occur from extension of inflammation from neighbouring organs.
The morbid changes which the pleura undergoes when inflamed consist of three chief conditions or stages of progress. (1) Inflammatory congestion and infiltration of the pleura, which may spread to the tissues of the lung on the one hand, and to those of the chest wall on the other. (2) Exudation of lymph on the pleural surfaces. This lymph is of variable consistence, sometimes composed of thin and easily separated pellicles, or of extensive thick masses or strata, or again showing itself in the form of a tough membrane. It is of greyish-yellow colour, and microscopically consists mainly of coagulated fibrin along with epithelial cells and red and white blood corpuscles. Its presence causes roughening of the two pleural surfaces, which, slightly separated in health, may now be brought into contact by bands of lymph extending between them. These bands may break up or may become organized by the development of new blood vessels, and adhering permanently may obliterate throughout a greater or less space the pleural sac, and interfere to some extent with the free play of the lungs. (3) Effusion of fluid into the pleural cavity. This fluid may vary in its characters.
The chief varieties of pleurisy are classified according to the variety of the effusion, should effusion take place. (1) Some pleurisies do not reach the stage of effusion, the inflammation terminating in the exudation of lymph. This is termed dry pleurisy. (2) Fibrinous or plastic pleurisy. In this variety the pleura is covered by a thick layer of granular, fibrinous material. Fibrinous pleurisy is usually secondary to acute diseases of the lung such as pneumonia, cancer, abscess or tuberculosis (3) Sero-fibrinous pleurisy. This is the most common variety, and produces the condition commonly known as pleurisy with effusion. The amount may vary from an almost inappreciable quantity to a gallon or more. When large in quantity it may fill to distension the pleural sac, bulge out the thoracic wall externally, and compress the lung, which may in such cases have all its air displaced and be reduced to a mere fraction of its natural bulk. Other organs, such as the heart and liver, may in consequence of the presence of the fluid be shifted away from their normal position. In favourable cases the fluid is absorbed more or less completely and the pleural surfaces again may unite by adhesions; or, all traces of inflammatory products having disappeared, the pleura may be restored to its normal condition. When the fluid is not speedily absorbed it may remain long in the cavity and compress the lung to such a degree as to render it incapable of re-expansion as the effusion passes slowly away. The consequence is that the chest wall falls in, the ribs become approximated, the shoulder is lowered, the spine becomes curved and internal organs permanently displaced, while the affected side scarcely moves in respiration. Sometimes the unabsorbed fluid becomes purulent, and an empyema is the result.
The symptoms of pleurisy vary; the onset is sometimes obscure but usually well marked. It may be ushered in by rigors, fever and a sharp pain in the side, especially on breathing. Pain is felt in the side or breast, of a severe cutting character, referred usually to the neighbourhood of the nipple, but it may be also at some distance from the affected part, such as through the middle of the body or in the abdominal or iliac regions. On auscultation the physician recognizes sooner or later “ friction,” a superficial rough rubbing sound, occurring only with the respiratory acts and ceasing when the breath is held. It is due to the coming together during respiration of the two pleural surfaces which are roughened by the exuded lymph. The pain is greatest at the outset, and tends to abate as the effusion takes place. A dry cough is almost always present, which is particularly distressing owing to the increased pain the effort excites. At the outset there may be dyspnoea, due to fever and pain; later it may result from compression of the lung.
On physical examination of the chest the following are among the chief points observed: (1) On inspection there is more or less bulging of the side affected, should effusion be present, obliteration of the intercostal spaces, and sometimes elevation of the shoulder. (2) On palpation with the hand applied to the side there is diminished expansion of one-half of the thorax, and the normal vocal fremitus is abolished. Should the effusion be on the right side and copious, the liver may be felt to have been pushed downwards, and the heart somewhat displaced to the left; while if the effusion be on the left side the heart is displaced to the right. (3) On percussion there is absolute dullness over the seat of the effusion. If the fluid does not fill the pleural sac the floating lung may yield a hyper-resonant note. (4) On auscultation the natural breath sound is inaudible over the effusion. Should the latter be only partial the breathing is clear and somewhat harsh, with or without friction, and the voice sound is a ego phonic. Posteriorly there may be heard tubular breathing with a ego phony. These various physical signs render it impossible to mistake the disease for other maladies the symptoms of which may bear a resemblance to it, such as pleurodynia.
The absorption or removal of the fluid is marked by the disappearance or diminution of the above-mentioned physical signs, except that of percussion dullness, which may last a long time, and is probably due in part to the thickened pleura. Friction may again be heard as the fluid passes away and the two pleural surfaces come together. The displaced organs are restored to their position, and the compressed lung re-expanded. Frequently this expansion is only partial.
In most instances the termination is favourable, the acute symptoms subsiding and the fluid (if not drawn off) becoming absorbed, sometimes after re accumulation. On the other hand it may remain long without undergoing much change, and thus \a condition of chronic pleurisy becomes established.
Pleurisy may exist in a latent form, the patient going about for weeks with a large accumulation of fluid in his thorax. the ordinary acute symptoms never having been present in any marked degree. Cases of this sort are often protracted, and heir results unsatisfactory as regards complete recovery.
In the treatment of early pleurisy, pain may be relieved by a hypodermic of morphia or the application of leeches. A purgative is essential. Fixation of the affected side of the thorax by strapping with adhesive plaster gives great relief. The icebag is useful in the early stages, as in pneumonia. The open-air treatment of cases is recommended, as the majority of the cases are of tuberculous origin. When effusion has taken place, counter irritation and the exhibition of iodide of potassium are useful. Dry diet and sahne purgatives have been well spoken of The most satisfactory method of treatment is early and if necessary repeated aspiration of the fluid. The operation (thoracenteszs) was practised by ancient physicians, but was revived in modern times by Armand Trousseau (1801–1867) in France and Henry I. Bowditch (1808–1892) in America; by the latter an excellent instrument was devised for emptying the chest, which, however, has been displaced in practice by the still more convenient aspirator. The chest is punctured in the lateral or posterior regions, and in most cases the greater portion or all of the fluid may be safely drawn off. In many instances not only is the removal of distressing symptoms speedy and complete, but the lung is relieved from pressure in time to enable it to resume its normal function.
In cases of chronic pleurisy after the failure of repeated aspirations, Samuel West reports well of free incision and drainage. He has reported cases of recovery of effusion, fifteen or eighteen months standing. Sir James Barr has advocated the treatment of these cases by the withdrawal of the fluid and the substitution of sterilized air and solution of supra-renal extract; others have introduced physiological salt solution or formalin solution into the cavity, after the removal of the fluid. Vaquez injects nitrogen into the cavity and reports a number of cases in which it prevented recurrence.