202. Protracted infective endocarditis: pathological anatomy and pathogenesis, complications.

In case of prolonged infectious endocarditis, the valve is a primary septic focus (the causative agent is more often streptococcus aureus). The aortic and mitral valves are more often affected.

Local changes:

Colonies of microorganisms and foci of necrosis with rapid ulceration are visible in the septic focus. Lymphohistiocytic and macrophage infiltration occurs around them, but neutrophilic leukocytes are absent, which is the difference between prolonged and acute endocarditis. Massive thrombotic overlays in the form of polyps form on ulcerative valve defects, which easily crumble, often calcify and quickly organize. This exacerbates existing valve changes or causes the formation of heart defects in primary septic endocarditis. Progressive ulcerative defects of the valve flaps lead to the formation of their aneurysms or perforation of the flap. Sometimes there is a rupture of the valve leaf with the development of acute heart failure.

General changes:

The vascular system. Common alterative-exudative changes are characteristic, mainly of the microcirculatory bed with the appearance of foci of fibrinoid necrosis in the walls of blood vessels. This often leads to the formation of microaneurysms. Their rupture, for example, in the brain, causes fatal hemorrhage, and thrombosis of the cerebral vessels causes the appearance of foci of softening of the central nervous system tissue. Vasculitis is the basis of hemorrhagic syndrome and multiple petechial hemorrhages in the skin and subcutaneous tissue, often with the subsequent development of foci of necrosis in the mucous membranes and serous membranes, conjunctiva of the eyes.

Kidneys. There is an immunocomplex diffuse glomerulonephritis, often combined with kidney infarctions and scars after them.

The spleen is sharply enlarged, its capsule is strained, when cut, the pulp is crimson in color, gives abundant scraping (septic spleen), spleen infarctions and scars after them are often found.

There is fatty and protein dystrophy in parenchymal organs.

The musculoskeletal system. Circulating immune complexes often settle on the synovial membranes, contributing to the development of arthritis.

Pathogenesis:

Complications:

Thromboembolic complications are found very often, since the source of thromboembolism — thromboendocarditis in the vast majority of cases is located in the left half of the heart. Thromboembolism often takes on a widespread character and dominates the clinical picture of the disease — thromboembolic syndrome. Embolism causes heart attacks in the lungs, spleen, kidneys, retina, skin necrosis, gangrene of the extremities, intestines, and foci of softening in the brain.

05.12.2021

Head Department of Pathological Anatomy, Federal State Budgetary Educational Institution of Higher Education Rost State Medical University

Ministry of Health of the Russian Federation

Doctor of Medical Sciences, Associate Professor Todorov S.S.

190