The intensity of a pericardial friction is increased when the patient bends forward at the end of a full inspiration or when the stethoscope is pressed firmly over the præcordial region; and in the last-named case it becomes distinctly grazing and rubbing in character. In endocarditis these methods produce no difference in either the intensity or the character of the murmur. There is an endocardial thrill in endocarditis not present in pericarditis.
As soon as effusion occurs in pericarditis the absence of pain, the alteration in the character of the pulse, the great increase in dulness, and the disappearance of the adventitious sounds will decide the diagnosis.
Aortitis has most of the symptoms of endocarditis, but in addition the pulse is more rapid, the respirations are more hurried, and pain which shoots down the spine and is increased by motion is present in the præcordial region. Not infrequently aortitis is accompanied by cutaneous hyperæsthesia.
Acute inflammation of the aorta is exceedingly rare, and in the few cases observed has been complicated by very grave diseases. Indeed, Powell, Lebert, and Rindfleisch doubt its existence.
In the Medico-Chirurgical Transactions (vol. xlvii. p. 129) Moore gives a case where rigors, fever, intense and painful throbbing of the aorta, and embolic infarction of distant organs occurred, with symptoms so resembling those of endocarditis that few would venture to favor a diagnosis of aortitis during life.
The functional cardiac murmurs which occur in fevers are usually heard only at the base of the heart, while those of endocarditis are most frequent and distinct at the apex. There are no symptoms of obstruction present with febrile murmurs, while they are frequently present in endocarditis.
It is often difficult to determine whether an endocardial murmur is of old or recent origin: if during an attack of acute rheumatism an endocardial murmur is developed under daily examination, it is a certain index of acute exudative endocarditis. If a murmur exists at the first examination which is systolic, soft, and blowing in character, and not accompanied by the evidences of cardiac hypertrophy, there is good reason to believe that it is produced by an acute endocardial inflammation.
If, on the other hand, the murmur is rough in quality, diastolic, and cardiac hypertrophy exists, it cannot be regarded as a sign of acute endocarditis.
The rules for distinguishing murmurs due to interstitial endocarditis from functional murmurs will be given under the head of Cardiac Murmurs.
PROGNOSIS.—Exudative endocarditis is rarely a direct cause of death, but it seldom results in complete recovery. Acute mitral endocarditis terminates in permanent valvular disease in over 25 per cent. of the cases. The elements that will render the prognosis immediately unfavorable in any case are the symptoms of embolism or of metastasis. Sudden splenic enlargement, with tenderness over its site, albuminuria or hemiplegia, when accompanied by the physical signs of acute insufficiency or perforation of a valve with cyanosis, dyspnoea, and disturbance of the heart-rhythm, will render the prognosis exceedingly unfavorable. All these symptoms are diagnostic of acute ulcerative endocarditis, and therefore when the signs of endocarditis appear during the course of pyæmia, diphtheria, or other septic condition, the liability to these conditions must be considered.