32 Diseases of the Heart.
The SYMPTOMS of pyopericardium are those of acute or chronic pericarditis, with marked depression. The physical signs are the same. Indeed, there is no certainty in the diagnosis. Where there is, the operation of paracentesis is strongly indicated. Free incision of the pericardium has been recently practised by Rosenstein and by Samuel West33 for purulent pericarditis.
33 The Lancet, Dec., 1883.
Pneumopericardium.
Pneumopericardium, or accumulation of air in the pericardial sac, is a very rare affection. Yet Laennec34 has stated that in his opinion air as well as fluid accumulates in the pericardium in all diseases just prior to death. Pneumopericardium may be associated with fluid, and may or may not be attended with inflammation of the pericardium. As the pericardium is a closed sac, air does not readily gain entrance. But it may do so through perforations of the walls by stabs or gunshot wounds, or by openings communicating with the oesophagus, lung, or stomach. Air is then drawn into the sac during the contractions of the heart. Cases are on record of perforation of the sac with a knife,35 and through the oesophagus by means of a sword swallowed by a juggler.36 Sometimes the perforations communicate with organs that contain gas, as the stomach or intestine or the oesophagus. Graves has recorded a case in connection with abscess of the liver. When the pericardial sac is intact, the distending gas may arise from decomposing fluid in the pericardium: it is supposed that it may even be secreted by the blood of the coronary vessels. Pure air, such as we breathe, is never developed in the sac.
34 Traité de l'Auscultation mediate, chap. xxiii.
35 Flint, Diseases of the Heart.
36 Walshe, Diseases of the Heart.
The accumulation of air in the pericardium which is sometimes noticed after death has been declared by many to be the result of the death-struggle. But it most likely occurs shortly before life ceases. In such cases the source of the air or gas must be the blood, for it is well known that blood contains several gases which may leave the corpuscles and fluid in which they are held mechanically.
The DIAGNOSIS of the condition under consideration is difficult, since we must chiefly depend upon the signs elicited by percussion. The general indications are a feeling of oppression in the præcordia, a sense of suffocation, fluttering of the heart; these, however, would only point to some functional disturbance. Percussion shows a preternatural resonance over the heart, the area of cardiac dulness being restricted and indistinct in proportion to the amount of air or gas contained in the sac. Emphysema of the margins of the lungs which overlap the front of the heart may give the same resonant sound, but it is not likely that emphysema of the lungs would be confined to their margins only.