CHAPTER III.. Endocarditis.

ENDOCARDITIS.

If the symptoms of pericardial diseases are well defined, we cannot say the same of diseases of the heart, properly so-called. Such affections often pass unnoticed, being detected only on post-mortem examination. Moreover, cardiac diseases are rare. Very frequently they are only of a secondary nature, accompanying or following better recognised conditions, such as infectious diseases, post-partum infections, etc.

=Causation.= Endocarditis, i.e., inflammation of the endocardium and valves, is rarely primary, simple and benign. It was formerly thought to be the result of chills or of the rheumatic diathesis. These simple forms of endocarditis usually escape observation, though careful examination in the first instance reveals them.

Much more frequently, however, endocarditis is secondary, malignant, infectious and infecting. This variety occurs as a complication of post-partum infection or of very serious general conditions, such as peripneumonia, gangrenous coryza, aphthous fever, tuberculosis, etc. To detect it, not only must the original disease be accurately diagnosed, but all the changes the disease is producing in important organs must be followed.

While it is generally admitted that all forms of endocarditis, even of the most benign character, are originally due to infection, it is certain that in those of the second group the organisms which have entered the bloodstream through a lesion of the uterus, lung or other tissue, are endowed with very great virulence. They attack some point on the endocardium, and produce either ulcerations which become covered with fibrous clots, or exuberant new growths of a pathological nature, which generally are papilliform, fragile, and prone to become detached by rupture of their pedicle and thus to be launched into the general circulation and to form emboli. The surface of these infected vegetations, like that of the ulcerations, becomes covered with fibrinous clots, which are readily loosened, form emboli in their turn, and infect distant organs.

=Symptoms.= The general symptoms of infectious endocarditis are by far the most important. They consist of prostration, loss of appetite, severe thirst, and high temperature. The local symptoms consist principally of murmurs: soft murmurs due to insufficiency of the auriculo-ventricular valves, heard during systole, particularly opposite the point of the heart where the cardiac shock is most clearly felt. This fact differentiates them from the murmurs of chronic endocarditis, which are usually due to aortic contraction, and are accompanied by a systolic sound heard at the base of the heart, more in advance and at a higher point than those now under consideration.

These murmurs or souffles furthermore vary in intensity and in character, according to whether the endocarditis results from post-partum infection, pyæmic disease, or some other cause.

=Diagnosis.= The diagnosis of endocarditis has not yet been the object of really careful study in bovine pathology, but there is no doubt that it can often be detected by patient examination.

=Prognosis.= The prognosis is very grave, and patients may die in a few days.

=Treatment= comprises vigorous local stimulation over the cardiac area, the administration of antithermic and antiseptic drugs, such as salicylate of soda, or of digitalis, sparteine or other cardiac tonics.

Pathologists have also described, chiefly as post-mortem curiosities of interest to pathological anatomists, various diseases and lesions due to insufficiency or contraction of the auriculo-ventricular, aortic, and pulmonary openings, lesions due to infectious myocarditis, to the presence of parasites and to other causes.

The symptoms of these various diseases or lesions in bovine animals are still too imperfectly understood to permit of more than a very limited description.

In the present state of our knowledge, diagnosis would always be of an uncertain character, and for this reason we do not propose to deal with them at present.