Capillaroscopy

Capillaroscopy is a method of visual examination of capillaries in vivo. The full name of the method is wide-field capillaroscopy of the nail bed. The study is carried out with a small increase in the microscope (x12-40), the object of observation is the distal row of capillaries of the nail bed (eponymichia). The use of a small magnification significantly expands the field of view, which makes it possible to study not only individual capillaries, but also the capillary network of this site as a whole. The choice for the study of the nail bed is determined by the characteristic location of the capillaries in this area.

[1], [2], [3], [4], [5], [6], [7], [8],

Why is capillaroscopy performed?

Differential diagnosis of primary and secondary Reynaud syndrome, early diagnosis of systemic scleroderma.

How is capillaroscopy performed?

The study is conducted in reflected light using a stereomicroscope and a source of cold light. To achieve permeability of the epidermis, a small amount of immersion oil is applied to the area under study.

Interpretation of results

In healthy individuals with capillaroscopy, the capillaries of the nail bed represent the correct series of parallel, identical in size and shape P-shaped loops, evenly distributed along the edge of the nail bed. In norm on 1 mm edge of a nail bed it is necessary 8 capillaries and more.

The main capillaroscopic signs of a lesion of microcirculatory vessels are changes in the size and number of capillaries. The most frequent changes in size are manifested in the form of dilatation of varying degrees of severity. The diameter most accurately reflects the change in size. The length of capillaries due to individual characteristics can vary significantly in the hotel population and therefore is not used as a rating criterion. As a result of the destruction, the reduction of the capillary network is observed, that is, a decrease in the number in a certain area. The decrease in the number can be expressed in different degrees, up to the formation of deprived capillaries, so the avalanches are being washed in.

As a result of damage and disruption of the integrity of the capillary wall, the erythrocytes are released into the perivascular space, where hemosiderin deposits are formed, which, with capillaroscopy, are visible as a series of successively located points between the capillary apex and the edge of the nail plate.

Less often extravasates are represented by large drainage foci consisting of several small hemorrhages. Another important sign of the defeat of microcirculatory vessels is a change in the shape of the capillary loop. Pathologically altered capillaries can take bushy, spiral or other forms. The most important are the bush capillaries. This is a few capillary loops connected at the base and protruding from the neoplasm of the capillaries. Their number reflects the intensity of neoangiogenesis.

Separate capillaroscopic signs and their combinations are characteristic for various diseases. Among the systemic diseases of connective tissue, the greatest sensitivity and specificity of capillaroscopic changes is observed in systemic scleroderma. Characteristic for systemic scleroderma signs - varying degrees of dilatation and a decrease in the number of capillaries with the formation of avascular fields. In most cases, it is possible to identify the dominant changes. Structural changes of capillaries in SSD reflect a certain stage of development of microangiopathy.

Changes in capillaries and capillary networks progress in this sequence: dilatation of capillaries → destruction of capillaries → formation of avascular regions → growth of bush capillaries → remodeling of capillary network. On the basis of characteristic combinations of features in the conduct of capillaroscopy, capillaroscopic types of microangiopathy are distinguished in SSD:

1. early type - a large number of dilated capillaries with a small decrease in their number; avascular regions or absent, or single and minimal extent;
2. transitional type a reduced number of capillaries and simultaneous detection of dilated capillaries and avascular regions;
3. late type - a significant reduction of blood vessels and large avascular regions with single capillaries or complete absence of dilated capillaries.

For each type of microangiopathy, characteristic signs of activity are distinguished. Extravasates associated with dilated capillaries reflect the intensity of the destruction of capillaries and activity, and microangiopathies in the early type of changes. In late type, signs of activity of microangiopathy, bush capillaries indicate intensive processes of neoangiogenesis and are associated with avascular regions. In the transitional type, signs of activity of microangiopathy, characteristic for both early and late types, are noted. Capillaroscopic changes are detected in the early stages of the SDS and precede the development of characteristic clinical signs that determine the importance of the method of research in diagnosis of the disease.

The great importance of capillaroscopy is the ability to differentiate the primary and secondary phenomenon of Raynaud - the first clinical manifestation of SSD. In contrast to the Reino-associated phenomenon, in the primary Raynaud phenomenon, capillaroscopic changes are absent or represented by a small dilatation of individual capillaries with their normal number. The severity and evolution of capillaroscopic changes correlate with the course of the disease and visceral pathology.

Characteristic capillaroscopic changes allow differentiating SSA from other diseases of the scleroderma group (diffuse eosinophilic fasciitis, adult sclerosis of Buschke, scleromixedema, generalized morpha), in which these changes do not reveal. In addition, capillaroscopy is of great importance in the differential diagnosis of SDS with the Reynaud phenomenon associated with other systemic connective tissue diseases: dermatitis (loli) myositis, systemic lupus erythematosus and rheumatoid arthritis, the clinical manifestations of which in the early stages may not be specific enough. The most pronounced changes in the form of a large number of significantly dilated and bush capillaries, avascular regions and massive extravasates are observed with dermatitis (poly) myositis. These changes are very similar to the changes observed in the SSD, but are more pronounced. With dermato (poly) myositis, the dynamics of capillaroscopic changes, which is associated with the evolution of the disease, is faster compared with the SSS. SSD-like changes in capillaries are found even in the case of SSWT. In a part of patients with SLE, capillaroscopy reveals moderately dilated capillaries, a spiral-like deformation of capillaries, an enhanced pattern of subpapillary plexuses, but the specificity of these changes requires evidence. In RA, capillaroscopic changes are presented in the form of thinning (decreasing diameter) and lengthening capillary loops; the number of capillaries usually does not change.

Factors affecting the result of capillaroscopy

Capillaroscopy may be difficult in patients with severe flexion contractures of the fingers.

[9], [10], [11], [12], [13], [14]