Once the blood in the legs starts to stagnate it causes raised venous pressure called venous hypertension. This causes seepage of through the thin walled capillaries leading to leg swelling. The CVI that develops due to DVT is called post-thrombotic syndrome. 30% of the patients with DVT develop post-thrombotic syndrome within 10 years.
CVI worsens with the passage of time and the sooner it is treated, the better the chances of recovery. The problem will never go away by waiting. The symptoms include:
In untreated cases the venous pressure rises to such high proportion that the fragile thinnest veins (capillaries) burst and the overlying skin becomes reddish brown in colour and is very sensitive to being broken if scratched or injured. The burst capillaries cause local tissue inflammation and internal tissue damage. This is the formation of ulcers which are difficult to heal and become infected. If still these are not treated they spread to the surrounding tissue and cause cellulitis. CVI leads to secondary varicose veins.