BY FRANK DONALDSON, M.D.
Pleurisy.
DEFINITION.—Inflammation, partial or general, of one or both pleuræ.
SYNONYMS. Pleuritis ([Greek: pleuritis]) morbus lateralis; Morbus pleuriticus (Celsus); Pneumona pleuritis (Cullen). Fr. Pleurésie; Ger. Seitenstich.
HISTORY.—Pleurisy derives its name from the accompanying pain in the side, usually its most prominent symptom. In the sense in which Hippocrates used the word [Greek: pleuritis], it meant all kinds of pain in the side, especially such as are of a violent character. Pleurisy was mentioned by Celsus, and was still better defined by Galen. Æctæus, however, was the first to describe it with precision and to speak of its treatment. These ancient authors viewed the disease as seated in the layer of the pleura lining the ribs or external parietes of the chest. More modern writers contended that the disease was more frequently in the expansion of the pleura over the lungs and other parts. Boerhaave and Van Swieten contended for the separate and distinct affection of the pleura. Sydenham, Hoffman, and Morgagni believed that the pleura and the substance of the lung were generally both implicated. Pinel was the first to definitely establish the difference between pleurisy and pneumonia from the anatomical lesions. Laennec laid the foundation of our present knowledge. He was followed by Andral, Chomel, Louis, and Cruveilhier in Paris, and by Forbes and Williams of London and Stokes of Dublin. They demonstrated, by the physical signs and general symptoms during life and by the post-mortem lesions, that inflammation may commence in and be limited to the pleura in some cases, and in others that it may extend to and involve the lungs. Again, they showed that in some instances the lung may be inflamed without involving the pleura generally, yet that in the large proportion of cases the disease may originate in one organ and extend in a greater or less degree to the other, thus implicating both of them. Previous to Laennec the incomplete anatomical knowledge of the nature of the serous membrane, the pleura, as a capsule of the lungs, and the thoracic organs and walls, as well as the theoretical views of the nature of inflammation as a morbid process, led to erroneous views. Their diagnoses were made from general symptoms only. Pleurisy was considered the more common disease. Avenbrugger, Corvisart, and Laennec, by their discoveries of the accurate physical modes of exploration of chest diseases, gave far more reliable data for differential diagnosis. Now we have, in addition to the general symptoms, the modern refinements in auscultation and percussion, the delicate measurements of Woillez's cyrtometer, Ransome's stethometer, and Pravaz's and Alex. Wood's hypodermic exploring-needles to enable us to attain great accuracy in the diagnosis.
CLASSIFICATION.—Pleurisy is one of the most common diseases of the respiratory apparatus. Though apparently simple, careful study shows it to be extremely complex. It occurs in very different forms and in a great many modifications, according to the producing causes and the numerous lesions which follow its course. We might classify the forms of pleurisy, according to their causes, as primary or secondary, tubercular, traumatic, etc.; or we could designate them according to their anatomical lesions, as dry pleurisy, pleurisy with effusion, general or parietal pleurisy, encysted, multilocular, purulent, hemorrhagic, etc. A methodical classification of all these forms is difficult if we attempt to base it upon the prominent characteristics or the lesions. We prefer a classification which enables us to study separately the clinical varieties which are most frequently met with, and therefore the most important. The symptomatology shows that the inflammatory process in pleurisy is of different degrees of intensity. We propose for our study to divide them into two main groups, according to the nature of the exudation:
| Fibro-serous pleurisy, | Acute, Chronic. |
| Purulent pleurisy, | Acute, Chronic. |
They may be local or general. When they result from disease of neighboring parts, they are generally local. Each of these groups comprehends primary and secondary varieties.
In the first, we have an exudation resembling the plasma of the blood. The effusion is not serous, for the fluid is spontaneously coagulable, whereas serum is not. It is not properly termed fibrinous, for it contains more albumen than fibrin. Fibro-serous is the most accurate term by which to designate it. The watery portion gravitates to the lowest part of the cavity, while the plastic deposit is thrown out over the two surfaces of the pleura. In the most acute forms the general symptoms, especially the pain and fever, are well marked. The exudation is at first largely fibrinous, but it is afterward more fluid in its character. In milder cases, the latent variety of the older authors, frequently designated as the subacute form, the subjective symptoms are so slight that the individual is not aware of his condition until the exudation, which is largely sero-fibrinous, mechanically interferes with his respiration. When first recognized these cases are really often chronic. They frequently remain sero-fibrinous in their character for a long time. Sometimes they become sero-purulent (the intermediary variety), and later purulent. Purulent pleurisies (empyema) are those where pus is the product of the inflammatory action. They may be acute (empyema d'emblée) or the result of transformation of acute or chronic fibro-serous pleurisies.