The most frequent cause of pleurisy is, as has been said, the bacillus of Koch.
Children are especially liable to em pyerna following pnemnonia; pneiimonia caused empyeina in 50 per cent. of per sonal cases; all were of severe type. A tuberculous family history exerts little influence on empyema. In about one sixth of the eases the empyema was sac ciliated; the pnemnococcus was found in 50 per cent. of the eases in which examination was made; the strepto coccus in 22 V, per cent.; the staphylo coccus in 8 per cent.; the tubercle ba cillus in 4 per cent.; and no bacterimn in 16 per cent. The pneumococcus pro duced the most virulent infection. J. A. Hartwell (Med. NeWS, July 13, 1901).
Pathology.—When the inflammatory process sets in, the pleura becomes thick ened, and this, besides the inhibition of the lubricating secretions that occurs, gives rise to a friction-sound: one of the first symptoms of pleurisy to present it self, as well as one of the last to dis appear.
The lubricating fluid is rather in creased as an effort on the part of nature to repair the damage done to the surfaces by their congested, uneven thickening. This fluid becombs gradually so plentiful that at times it is sufficient to form serous effusion. If the inflammatory product should continue or if pyogenic microbes invade the cavity-, suppuration. results, and we have empyema.
Case of calcareous einpyema followed by death. Post-mortem the lung was collapsed and the pleura thickened and coated on its whole internal surface by a, thick crust of calcareous deposit, in cluding the upper surface of the dia phragm. The sour, milk-like odor of the discharge toward the la,st suggested that lactic-acid fermentation was taking plac.e within the cavity. T. Carwardine (Bris tol Medico-Chir. Jour., Mar., '98).
Prognosis.—Cases seen early result favorably under proper treatment; hence the rule that cases of empyema should never be allowed to grow old.
Six hundred and tifty-six ellSeS of em pyema in children, with one 'hundred and four deaths. The younger the patient, the greater the risk of fatal termination.
The sooner the purulent effusion re moved, the quicker the recovery. Dan ger to life is chiefly due to complica tions: pericarditis, peritonitis, septi extnia. Wightman (Lancet, Nov. 30, '95).
Considerable practical prognostic im portance attaches to the bacteriological study of the pus of empyema. Thus, empyenut in childhood, caused by the pneumococcus, is quite benign and runs a rapid course to recovery, while that caused by the streptococcus runs a slower course and is more serious. Tuberculous pleuritis is a chronic process usually ter minating. fatally, or lasting for years until tuberculosis or an intercurrent affection carries ofr the patient, or he gradually succumbs to prolonged hectic amyloid disease and asthenia. Errors in diagnosis inay be caused by the tendency to sedimentation of the pus, when an ex ploring-needle may withdraw clear fluid from the upper layer instead of pus.
Joseph :McFarland (Phila. Med. Jour., Sept. S, 1900).
Very much depends upon the nature of the infection. The readiness with which the compressed or retracted lung returns to fill the cavity marks the difference between a ease of favorable and rapid progress to complete healing and a pro tracted one, ending possibly in extensive rib resection with deformity. As to the bacteriolog-y, the two main features are the comparative frequency of staphylo cocci and the rarity of the diplococcus pneumonive. Some doubt must remain as to the exact relationship which the bac teria bear to the production of pus. W. F. Hamilton (Montreal Med. Jour.. Oct., 1900).
In all cases the most serious conse qucmee of the affection is deformity, and in children lateral spinal curvature is likely to occur. Pytnia and septiaemia will result from putrid ernpyema; and general miliary tuberculosis may follow a localized tuberculous pleurisy which becomes purulent. Rupture into the bronchi, trachea, lungs, with immediate death from suffocation, or into the stom ach after perforating the diaphragm, are among the possibilities.