The soft and friable vegetations may be torn into long shreds by a forcible blood-current, and subsequently may excite endocardial inflammation where they come in contact with the walls of the heart-cavity, or they may break off and form emboli. A fibrinous string upon a flap of the aortic valve is not infrequently driven down and back by a regurgitant current, so as to excite endocarditis in the mitral valve.
Some observers state that micrococci and bacteria are found in ulcerative endocarditis of a septic or diphtheritic origin, and they have given to it the name of mycosis endocardii. It is probable that these minute organisms are developed by the septic ulcerative process rather than that they are the cause of such processes. They appear as spheres, highly refractive, motionless, cohering in groups, without any stroma. Acids, alkalies, ether, and chloroform have no effect on them, so that they are not to be regarded as vegetable products.
The valvular ulcerations in this form of endocarditis give rise to the most diverse lesions. Masses may be detached from the diseased cardiac orifices, either from the fibrinous deposits on the valves or from ulcerations of the valves themselves, and, having entered the circulation, they will produce various symptoms in the organs and tissues to which they are carried.
It is important to make a distinction between the results produced by displacements into the blood-current of large masses and those arising from the entrance of molecular fragments. It is also to be remembered that the masses from the vegetations or ulcerated valves in ulcerative endocarditis are often stamped with a septic element which leads to the development of suppurative infarctions in different organs.
The size and site of the emboli are important, for they may be so large as to obstruct vessels of large size.
The femoral and even the external iliac may suddenly become impervious to the circulatory currents, on account of the presence of a large embolus from the heart.
When the arteries in the limbs are thus plugged, the result is generally an ischæmia, terminating often in gangrene. Capillary embolism may occur in a number of organs at the same instant, and give rise to a variety of lesions. When the cutaneous capillaries are obstructed ecchymotic spots are produced, followed by cellulitis. When the cerebral vessels are obstructed softening may occur, which, if the vessels are very small, may be developed without any evidence of obstruction to the cerebral circulation. If the obstructed artery is of large size, instantaneous hemiplegia and secondary softening will result.
Capillary emboli may have their seat in the vessels of the spleen, giving rise to infarctions and suppuration.
The kidneys may also undergo analogous changes. Rayer, without knowing the origin of these changes, has given an excellent description of them under the name of rheumatic nephritis.
In addition to the local lesions arising from these arterial or capillary emboli, the septic phenomena are most important. When typhoid symptoms, deep jaundice, and symptomatic intermittent fever are associated with acute endocarditis, it establishes its ulcerative character. In acute exudative as well as in ulcerative endocarditis, when the inflammation progresses rapidly, the valves soften and become less resistant than normal. As a result, they are stretched, bulged, or torn by the stream of the circulating blood-current.