PLETJBISY. 117 PLETIE.ODYNIA. the interior of the chest wall. These two layers are normally everywhere in contact and move upon each other freely durin<; 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 eU'usion 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 afi'ected 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 be absorbed, and complete recovery take place ; or the plastic exudate ma.y 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 serofibrinous fluid, pale yellowish in color, or bro^^^lish at times from cxtravasated 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 serioush' interfered with. Small quanti- ties of fluid are readily absorbed, but large effusions may persist for months unless reduced by surgical means. In some eases the effusion is limited to the diaphragmatic portion of the pleura (diaphragmatic pleurisy) ; in others only the portion Ijetween the lobes of the lung is involved (interlobular pleurisy ) . A liemorrhagic 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 evacuated 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 exawgerated 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. The physical signs of dry pleurisy are im])airecl motion on the affected side and a friction sound caused by the rubbing together of the inflamed surfaces. When the effusion has occurred, this sound disappears, there is a loss of pulmonary resonance, and dullness or flatness on percussion over the area occupied by the effusion. The side involved is larger than the other, the intercostal spaces are obliterated or bulge. The heart may be displaced upward or to one side, so that the apex beat is felt out of its normal place, or entirely hidden behind the sternum. A serofibrinous pleurisy may persist for months, and the lung, from the long-continued pressure, becotne permanenth' contracted, so that when the fluid is absorbed or drawn off it fails to return to its normal dimensions and to fill the whole cavity. Adhesions may help to pro- duce this condition. The treatment of dry pleurisy comprises rest in bed, saline catharsis, and relief of pain by the administration of sedatives or by counter- irritation in the form of a mustard plaster or the application of the electrocautery. Strap- ping the chest with long strips of adhesive plaster gives comfort by limiting respiratory movements. Pleurisy with effusion requires a somewhat dif- ferent plan of treatment. To favor absorption of the exudate, the diet is made light and dry, and daily concentrated doses of Epsom salt are given to promote elimination. The skin and kid- neys are also kept active with diaphoretic and diuretic medicines. Mild counter-irritation with mustard or iodine is useful in the later stages. When the effusion is large and resists all ordi- nary methods of treatment, aspiration of the fluid or part of it is practiced. This is accom- jjlished by puncturing the chest wall with a hollow needle attached to a suction pump. The operation is simple and not painful, and is some- times done merely to determine the nature of the exudate. The fluid is withdrawn slowly, the amount depending on the size of the effusion. In some cases a quart or more can be abstracted with safety. Frequently the withdrawal of a small amount will be followed by spontaneous absorption of the remainder. Purulent pleurisy — empyema — is treated by making an incision into the chest wall and allowing the pus to escape, washing out the cavity and draining it. This operation dates from the time of Hippo- crates and is not a serious procedure'. The cavity is gradually filled by the expansion of the lung and the falling in of the chest wall. Some- times it is necessary to remove portions of one or more ribs. Expansion of the lung is promoted by systematic breathing exercises. PLEURISY ROOT. One of the milkweeds. See Butterfly-Weed. PLEtTRGDYNIA ( Xeo-Lat.. from Gk. wXevpd, pleura, rib + 65v;>ti, odi/iie, pain). A rheumatic affection of the intercostal muscles on one side, characterized by acute pain in the side upon taking a full breath or coughing, and by tender- ness on pressure. The respiratory movements
