Home >> New International Encyclopedia, Volume 16 >> Plague to Polybius >> Pleurisy_P1


effusion, fluid, lung, cavity, membrane and dry

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PLEURISY (Fr. plcuresic. from Lat. pleuri sis, pleuritis, from Gk. rXetuarts, pleurisy, from 7rXevpd, pleura, rib). An inflammation of the pleura, the serous membrane investing the lungs. This membrane, like the pericardium (q.v.) and the peritoneum (q.v.), consists of two layers, a visceral and a parietal, the former closely at tached to the lungs, and the latter applied to the interior of the chest wall. These two layers are normally everywhere in contact and move upon each other freely during respiration, a lubricating fluid being secreted for this purpose. A space between the visceral and parietal por tions of the membrane, called the pleural cavity, exists only under pathological conditions, and may be occupied either by air or fluid.

Pleurisy may be acute or chronic, primary or secondary, plastic (dry) or characterized by an effusion of fluid. It occurs after exposure to cold; as a secondary process in acute diseases of the lung. as pneumonia, which is always accompanied by a greater or less amount of dry pleurisy; as a result of injuries; or as an effect of rheumatism. The most frequent cause, how ever, is tuberculosis; recurrent attacks of pleurisy are almost always tubercular in char acter.

In the dry or plastic form of pleurisy the affected area of the membrane becomes congested and opaque, roughened. and covered with a sheath ing of lymph, of variable thickness. The process may be arrested at this point, the exudate he absorbed, and complete recovery take place; or the plastic exudate may become organized and produce permanent adhesions between the two pleural layers. These adhesions are in the form of patches or bands, and in proportion to their extent limit the movements of the lungs in the chest cavity.

In pleurisy with effusion there is thrown out a varying amount of sero-fibrinous fluid, pale in color, or brownish at times from extravasated blood. In composition this closely resembles the serum of the blood. The effusion may be so small in quantity as to cause no symptoms and escape notice. When considerable

in amount, the lung is compressed, the heart and other organs displaced, and respiration and cir culation seriously interfered with. Small quanti ties of fluid are readily absorbed, hut large effusions may persist for months unless reduced by surgical means. In some cases the effusion is limited to the diaphragmatic portion of the pleura (diaphragmatic pleurisy) ; in others only the portion between the lobes of the lung is involved (interlobular pleurisy). A hemorrhagic effusion sometimes occurs during the course of certain malignant fevers and in cachectic states of the body.

A pleuritic exudate may become infected by pus-producing, bacteria which multiply very rapidly and soon convert the fluid into a purulent material. This condition is called empyema, and is a very grave complication. The pleural cavity is converted into what is practically a large abscess, which may evacuate itself by burrowing through the lung substance to a bronchial tube and being coughed up; or it may penetrate the chest wall; or make its way through the diaphragm into the peritoneal cavity and set up a general peritonitis. The affection is more com mon and less fatal in children than in adults. In the former a favorable result may be expected. particularly if the pus is early. Some cases recover spontaneously.

The most prominent symptoms of pleurisy are chills. fever, stitch in the side, and a dry, unpro ductive cough. The pain is at first severe, and is exaggerated with every movement of the body, by coughing, sneezing, etc. Respiration is diffi cult and shallow, and the patient lies upon his back or on the healthy side. After effusion has taken place pain is less marked, and the patient lies on the affected side, in order to give the healthy lung full play. In addition to these symptoms there exist general malaise. weakness, loss of appetite, and a quick pulse. Empyema is marked by irregular temperature. chills, and sweats.

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