Clinico-morphological forms of rheumatism

Assessment of process activity

The activity of the rheumatic process is assessed by two key morphological criteria. First, it is the presence of specific rheumatic granulomas. Second, the development of nonspecific exudative, as well as exudative-proliferative reactions.

Such nonspecific changes are localized predominantly in the cardiac tissues and in the interstitium of various internal organs. The cellular infiltrate consists mainly of lymphocytes and macrophages, occasionally admixed with eosinophils and neutrophils. In addition, vasculitis regularly develops in the microvasculature system.

Main forms of rheumatism

Four main forms of the disease are distinguished:

1. Cardiovascular form. It develops significantly more often than the others. Its mandatory component is rheumatic endocarditis. If inflammation encompasses both the endocarditis and myocardium, rheumatic carditis (rheumatic heart disease) is diagnosed. When combined involvement of absolutely all layers of the heart—endocardium, myocardium, and pericardium—occurs, it is referred to as rheumatic pancarditis.
2. Polyarthritic form. Characterized by involvement of large joints. Foci of connective tissue disorganization form in the synovial membrane, and synovitis develops. Vasculitis occurs, accompanied by marked hyperemia, and lymphoid infiltrates accumulate around the vessels in the form of cuffs. A serous or serous-fibrinoid effusion forms in the joint cavity. The most important feature of this form is that the articular cartilage is not involved in the pathological process, so joint deformation never occurs.
3. Nodose (nodular) form. Manifests as the formation of specific nodes and nodules under the skin. Most often they are localized on the extensor surfaces of large joints, along the spinal column, as well as in fasciae, tendons, and aponeuroses. Microscopically, such a node represents a focus of fibrinoid necrosis, which is densely surrounded by a cellular infiltrate of macrophages and lymphocytes. Over time, small scars form at the site of these nodules. This form generally proceeds against the background of concurrent heart involvement.
4. Cerebral form (Sydenham's chorea). Distinguished by predominant involvement of the brain. Morphologically, it manifests as arteritis, formation of microglial nodules, and dystrophic changes in nerve cells. In rare cases, focal hemorrhages are possible. Notably, involvement of other systems and organs in Sydenham's chorea is weakly expressed.

Rheumatic vasculitis

Involvement of the vascular bed in rheumatism is generalized and detected almost constantly. The microvasculature becomes the main target.

• In arteries and arterioles, fibrinoid changes develop, frequently complicated by thrombosis.
• In capillaries, active proliferation and subsequent desquamation of endothelial cells are observed—a process termed rheumatic endotheliosis. Simultaneously, peculiar cuffs of proliferating adventitial cells form around the capillaries.

A regular outcome of such vasculitis is sclerosis of the vascular wall, leading to the development of arteriosclerosis, arteriolosclerosis, and capillarosclerosis.

Complications and outcomes

During an acute rheumatic attack, absolutely all organs and systems of the body can be involved. Severe complications include superimposed infective endocarditis, the development of rheumatic pneumonia, focal or diffuse glomerulonephritis, and polyserositis.

Extracardiac manifestations are quite diverse:

• Serous membranes: development of adhesive processes in the pleural, pericardial, and peritoneal cavities.
• Skeletal muscles: appearance of foci of waxy necrosis.
• Skin: onset of rash and erythema annulare.
• Endocrine system: dystrophic and atrophic changes of the glands.
• Vessels: development of thromboembolic syndrome.

Disease outcomes are inextricably linked to the severity of cardiovascular damage. Directly during the rheumatic attack, there is a serious threat of acute cardiovascular failure and fatal arrhythmias. In the long term, established valve defects and cardiosclerosis inevitably lead to progressive chronic cardiovascular failure.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Morphology and stages of development of rheumatic granulomas
• Types and outcomes of rheumatic endocarditis
• Pathogenesis of thromboembolic syndrome in rheumatism
• Mechanism of development of waxy necrosis in skeletal muscles

Other topics in the "Rheumatic Diseases" section

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