When blood flow within a leg vein is compromised, blood pools within the foot and lower leg. This is known as venous stasis in the legs. It essentially means that the circulation is sluggish and blood is moving too slowly or only small quantities of blood are able to exit the leg. For venous stasis to to occur, the blockage or valvular incompetence has to occur in one of the major veins of the leg.
Venous stasis affects the entire blood circulation of the leg to some extent and even the flow of blood within unaffected vessels is impaired. This ultimately affects the supply of nutrients and oxygen to the tissues of the legs. The causes of venous stasis are discussed further under Venous Insufficiency of the Legs.
Signs and Symptoms of Venous Stasis
The more common signs and symptoms which are present to varying degrees from the outset (early stages) include :
- Leg swelling which may initially start up as swollen feet or ankle swelling only after standing or walking for long periods. It eventually reaches a point where there is noticeable edema of the legs all the time, which only eases upon lying flat or raising the legs.
- Leg pain while walking or standing for long periods may vary in intensity in character. It may be described as :
- sensation of tightness
The pain in the leg develops gradually and unlike problems in the leg arteries, venous claudication eases long after resting or only upon elevating the legs.
With time, additional signs and symptoms will become evident. The two most common causes of venous stasis are varicose veins which tends to occurs in the superficial leg veins while deep venous thrombosis (DVT) arises in the deep veins of the leg. The early symptoms may vary slightly depending on the cause but ultimately venous stasis results in the same effect on the affected area.
- Skin discoloration and darkening. This may start from a red to purple and blue hue and progress to a dark brown to almost black discoloration of the skin. With venous insufficiency there is a tendency for the darkening to occur on the inner part of the ankle or leg (medial aspect). Itching of the skin with dry, flaking skin may be the first cutaneous symptoms of venous stasis. It is broadly known as venous stasis dermatitis or venous eczema (picture below). Eventually this leads to a thickening and hardening of the skin known as lipodermatosclerosis.
Picture of Stasis Dermatitis (Eczema) from Dermatology Atlas (Samuel Freire da Silva, M.D.)
- Leg ulcer. Venous stasis leg ulcers (picture below) tend to occur on the medial aspect of the leg often just above the ankle joint. It is a slow healing or non-healing leg ulcer, which is irregularly shaped and usually painless unless it becomes infected. It often follows the development of lipodermatosclerosis and is a sign of a progression of the disease.
- Prominent leg veins (varicose veins) which may start as tiny visible blood vessels commonly referred to as spider veins (telangiectasia).
- Muscle weakness and cramping in the legs may occur to varying degrees from the early to late stages of the disease.