What are the causes of postphlebitic syndrome?

What are the causes of postphlebitic syndrome?

1. After phlebitis, a series of changes such as thrombosis in the deep vein system and dissolution, organization, and recanalization of blood clots damage the venous valves, hinder the return function of the deep veins, and cause venous hypertension, such as deep vein lesions such as the iliofemoral vein or carmine vein, which destroy the normal function of the veins. The venous pressure of the right ventricle directly affects the distal deep veins and their branches, especially when in an upright position, the pressure increases significantly. Tissue dystrophy is caused by venous congestion and secondary varicose veins.

2. Pathological changes of the skin are: slight intercellular edema in the epidermis, containing a small amount of lymphocytes and granular cells; obvious edema, collagen swelling, elastic fiber rupture, severe sharp infiltration of lymphocytes and plasma cells in the epithelial connective tissue. Blood vessels are thickened and dilated, damaged veins are thinned, and fibers are hardened and thickened.

3. Venous thrombosis can occur in various parts of the body, the most common being the great saphenous vein and its branches, and the rarest being the hamstring vein, subclavian vein, cephalic vein, expensive vein, and chest and abdominal wall veins. After superficial vein thrombosis of the lower or upper limbs, tissue edema is not likely to cause circulatory disorders; on the contrary, larger deep veins, such as the iliac vein, axillary vein, upper and lower veins, have narrow or occluded lumens, which hinder blood return and increase venous pressure, leading to congestion of capillaries and venules, tissue hypoxia, increased capillary osmotic pressure, and tissue edema.

4. When lymphatic vessels are compressed, edema becomes more obvious. In the future, if new blood vessels are formed or recanalized, collateral circulation is established, and blood circulation in the affected area will be maintained. If these new formations are well-structured, venous return will also be improved. It is difficult to restore when the venous valve is damaged; on the contrary, it will lead to chronic venous insufficiency, postphlebitic syndrome or partial thrombosis.