Perforation of the lung may occur and lead to the rapid discharge of pus through the bronchi. The discharge may be so rapid as to suffocate the patient, but the discharge may be gradual and recovery ultimately follow. Air usually gains ac cess to the sac: pyopneumothorax.
In some cases, especially those of tuberculous character, the pus may cause more or less extensive superficial necrosis of the lung and be gradually filtered through spongy lung into the bronchi. In these pneumothorax does not follow. In some cases the opening into the bron chi is valvular, and the pus is then dis charged intermittently.
Perforation of the lung rarely takes place before the empyema has existed six weeks or more. It may occur after free drainage has been established by opera tion, or spontaneous discharge through an intercostal space has occurred. Or the perforation of the lung and discharge through the bronchi may precede the in tercostal perforation. This occurred a year or two ago in a man who had a cir cumscribed empyema from perforation of the diaphragm by an appendiceal abscess.
Nowadays all such terminations, fortu nately, are rare, as necessary operations for the discharge of the pus are usually done early.
Diagnosis.—Though the diagnosis of pleurisy is usually easy, perhaps no dis ease within the thorax is more frequently unsuspected. The difficulties belong chiefly to the earliest and the latest stages. In the earliest the symptoms may be latent and thus render the diagnosis impossible. In acute dry pleurisy, if the friction-rub is present, the disease is easily recognized. If the rub is absent, it may be difficult to distinguish it from pleurodynia and intercostal neuralgia. In these latter affections there is no pyrexia and the tenderness is more marked along the course of the nerves than in pleurisy. In doubtful cases care ful repeated examination should be made over the area of pain, lest effusion occur and be overlooked and do much damage.
In the later stages when the effusion is abundant, the diagnosis may be very difficult. In this condition the diagnosis is based upon the enlargement and im mobility of the chest, dullness with loss of elasticity over the dull area, absence of vocal thrill, weakness or absence of respiratory sounds, and the displacement of the cardiac impulse toward the unaf fected side. Of these signs the cardiac
displacement is the most important: it, in fact, furnishes the key to the condition.
If there be high-pitched tympanitic resonance below the clavicle, it is very characteristic of fluid below. In mod erate effusions these signs may be want ing or indefinite, and the case may closely simulate pneumonia. This history of initial chill, the rapid rise of ture, the dyspncea, the rusty sputum, and the dullness without the wooden char acter usually serve to differentiate monia. But pleurisy, especially that due to the pneumococcus, may simulate this history closely: there may be the initial chill, rapid rise of temperature, noes, tubular breathing, with high pitched expiration, all these without dis placement of the heart.
Crepitation in the lower portions of the lung on the affected side is of great importance in diagnosis of slight pleural effusion. In cases of large effusion it is of little significance. One will hear, on careful auscultation over the lower por tion of the lung, a fine crepitation that is present with inspiration only, and con sists of small, somewhat moist riles that differ from the rale of beginning pneu monia in being moist, and from c•epi tatio minx in that all of the riles seem of the same size and are extremely fine; in resolving pneumonia they are larger and more liquid. W. Janowski (Zeit. f. klin. Med., 36. H. 1, '00).
An early symptom of pleurisy with ef fusion noted in nineteen cases consisted in a narrowing of the intercostal spaces and increased rigidity of the intercostal muscles on the affected side. It is espe cially marked in children and is due to abnormal contraction of the interosseous muscles analogous to the muscular con traction which occurs in joint affections. Przewalski (Amer. Medicine, May 31, 1902).
In case of doubt as to the presence of effusion, exploring the chest with the aspirator usually determines the charac ter of the case. With extreme care as to aseptic precautions there is no risk in ex ploring the base of the chest; in the rare eases of localized exudation at the apex there is some danger of wounding the large vessels. Not infrequently, how ever, puncture fails on account of the situation of the fluid—as in matic pleurisy, its circumscribed charac ter, or its density.