When your heart beats it pumps the blood around the body through the circulatory system which consists of hollow living tubes. These tubes are of three types – the arteries carrying oxygenated blood away from the heart and veins carrying deoxygenated blood towards the heart. The third type is the lymphatics.

Veins are flexible hollow tubes with flaps within them called valves. Blood return to the heart is passive and assisted by the movement of the muscles of the arms and the legs. When your muscles contract these thin veins the blood moves by opening these valves and when the muscles relax the valves close to allow blood to move in one direction through these veins. The veins become progressively larger as they go towards the heart. The largest ones are the superior vena cava bringing blood from your head and neck and arms back to the heart while the inferior vena cava brings blood from the lower limbs and abdomen back to the heart.

If these valves within the veins get damaged due to any reason, the blood flows in both the directions as they leak backward.

The wall of the leg veins deteriorate and the valves get damaged and become incompetent leading to all the multiple diseases they cause. This allows the blood to flow back towards the foot in the superficial or the deep venous systems. It is called reflux. When the superficial veins become damaged and severely dilated the blood flows back towards the foot and thus much of the blood has to go by the deep system towards the heart.

The excess blood makes the deep system dilate and thus this also becomes incompetent. When the blood is not pumped effectively back to the heart it pools in the legs and does not reduce walking thus increasing the static pressure. This is called chronic venous insufficiency (CVI) leading to edema, skin changes and ulceration.

Normally in all of us during circulation small amounts of fluids and proteins leak from the arteries and veins. Lymphatic veins bring this protein risk fluid back into circulation

What is a venous disease?

These fall into two broad categories - Blockage from a blood clot (thrombus) and inadequate venous drainage (insufficiency)

These include:

• Blood clots - these could for in any vein of the body – legs, arms, internal organs (kidney, spleen, intestine, liver, pelvis), in the brain (cerebral vein thrombosis), in the kidneys (renal vein thrombosis), in the lungs (pulmonary embolism). The legs are the commonest site. The commonest causes are cancer, immobility, inherent tendency for blood clotting, pregnancy, and contraceptive pills.
• Deep vein thrombosis (DVT) is a blood clot occurring in the veins of the extremities (legs and arms). They are more difficult to diagnose because only 50% of the DVT patients are symptomatic. The patients complain of pain on walking, leg swelling, heaviness in legs and fullness. Primary DVT occurs in the absence of any cause and caused by an inherent tendency to clotting. Secondary DVT occurs where a cause is known like immobilization after surgery or cancer.
• The clot in the vein blocks it and this causes back pressure in the vein which leaks fluid into the tissue causing swelling. The clot itself produces inflammation, redness, and tenderness.

Though clots in the legs occur quite commonly, the condition is not dangerous but should they break free when they travel via the blood to the lungs giving rise to the fatal condition - pulmonary embolism(PE). Without treatment, 25% of the clots will break free and travel via the circulation to the lungs. The complications of PE are shortness of breath, marked exercise limitation and death.

The diagnosis is made on ultrasound and is very reliable above or at the knee which is the commonest site to send off an embolus to the lung. Below knee, ultrasound is not very reliable because the venous anatomy is not very reliable. If needed an MRI or a venogram is done.

The treatment is anticoagulation which dramatically reduces the chances of PE. We start with injectable heparin and then turn onto oral anticoagulation (warfarin). It should be continued for 3-6 months and needs frequent monitoring of blood thinning levels. This treatment reduces the incidence of PE from 25 - 5% over the first year but the chances of bleeding increase from 2-3%.

There are two areas of controversy:

1) Thrombolysis (clot-dissolving therapy)

2) use of blood thinners for clots in a calf

Thrombolysis carries a serious risk of bleeding and is only recommended in very serious cases. In the second case, most prescribe blood-thinning drugs for calf clots.

Superficial venous thrombosis or thrombophlebitis - this is a blood clot forming in the vein close to the skin surface. This appears as a red streak along the course of the vein and is accompanied by inflammation. Cancer may be the cause of many such episodes (Trousseau's syndrome).

It is more annoying than dangerous because clots rarely break down and travel to the lungs. Rarely these clots do not travel to the lungs unless they move from the superficial to the deep veins and are thus not dangerous. They are the most painful. The treatment consists of non-steroidal anti-inflammatory drugs (Ibuprofen) and rarely blood thinning medicines.

Chronic venous insufficiency - It happens when drainage from the lower limb is not adequate for a long period of time. It is due to blockage of the vein or reflux of the blood backward due to faulty valves. The commonest cause is DVT and 1/3 DVT patients develop CVI within 5 years. The venous valves are defective due to clot retaining scarring or congenital defects.

It is characterized by pooling of the blood, chronic leg swelling, increased pressure in the legs, increased leg pain. Increased pigmentation or discoloration of the skin and leg ulcers called stasis ulcers. The swelling increases on dependency and improves on elevation. It is worse in warm weather and during menstruation.

Skin color changes are due to leakage, destruction, and deposition of red blood cells in the skin. These changes are not dangerous but depict severe long term process.

Treatment is aimed at improving the blood return to the heart and decreasing fluid escape from the veins. Leg elevation, compression stockings, specialized care of ulcers and occasional use of diuretics constitutes the therapy. There are hardly any surgical options.

Varicose and spider veins - are abnormally dilated veins caused by weakening of the blood vessel wall. It is due to superficial venous insufficiency. They are commoner in women and 50% of the patients being treated have a family history. It is due to damage to the vein valves due to structural abnormality.

Obesity, pregnancy, prolonged standing, sedentary life may be responsible.

Symptoms of pain, swelling and heaviness are less severe in the morning and increase as the day progresses.

In neglected they may progress to color changes in the skin and leg ulcers, skin infection, blood clots, and spontaneous bleeding.

Standard treatment is weight loss in obese, exercise, blood pressure control and stockings

The stockings are worn in the morning when the veins are empty. After getting ready elevate the legs in bed for a few minutes to empty the veins. The veins are elevated above the level of the heart

Venous ulcers - are caused by stasis of the venous blood. They are an open wound that refuses to heal and keep returning. They are typically present below the knee and commonly found above the ankle on the inner side.