Thrombosis, Deep Vein: From 1 Different Sources
The formation of a thrombus within deep-lying veins in the leg. The cause is usually a combination of slow blood flow through 1 part of the body (such as when sitting for long periods or when the tissues are compressed, as occurs in long-haul aircraft flights) and an increase in the clotting tendency of the blood, which occurs with dehydration, after surgery or injury, during pregnancy, and in women taking oral contraceptives. Deep vein thrombosis may also be caused by polycythaemia. Deep vein thrombosis is common in people with heart failure and those who have had a stroke or who have been immobile for long periods. Clots in the leg veins may cause pain, tenderness, swelling, discoloration, and ulceration of the skin, but they can be symptomless. A deep vein thrombosis is not necessarily serious in itself, but part of the clot may break off and travel in the bloodstream to the lungs. This is known as a pulmonary embolism.
A diagnosis is made by doppler ultrasound scanning.
Treatment depends on the site and extent of the clots.
Small clots may not need treatment if they are confined to the calf and the patient is mobile.
Otherwise, anticoagulant drugs or thrombolytic drugs are given.
If there is a high risk of a pulmonary embolism, thrombectomy may be performed.
A blood clot that may partially or wholly block the flow of blood through a blood vessel... thrombosis
See HEART, DISEASES OF.... coronary thrombosis
VEINS that have become stretched and dilated. (See VEINS, DISEASES OF.)... varicose veins
The prominent vein which runs from near the bend of the elbow upwards along the inner side of the upper arm.... basilic vein
See thrombosis, deep vein.... deep vein thrombosis
One of 3 veins on each side of the neck that return deoxygenated blood from the head to the heart. The internal jugular, the largest of the 3 (internal, external, and anterior), arises at the base of the skull, travels down the neck alongside the carotid arteries, and passes behind the clavicle, where it joins the subclavian vein (the large vein that drains blood from the arms).... jugular vein
A vessel that returns blood towards the heart from the various organs and tissues of the body. The walls of veins, like those of arteries, consist of a smooth inner lining, a muscular middle layer, and a fibrous outer covering. However, blood pressure in veins is lower than in arteries, and the walls of veins are thinner, less elastic, less muscular, and weaker than those of arteries. The linings of many veins contain folds, which act as valves, ensuring that blood flows only towards the heart. Blood is helped on its way through the veins by pressure on the vessel walls from the contraction of surrounding muscles. (See also circulatory system.) A... vein
When coronary arteries, narrowed by disease, cannot supply the heart muscle with su?cient blood, the cardiac circulation may be improved by grafting a section of vein from the leg to bypass the obstruction. Around 10,000 people in the United Kingdom have this operation annually and the results are usually good. It is a major procedure that lasts several hours and requires the heart to be stopped temporarily, with blood circulation and oxygenation taken over by a HEART-LUNG MACHINE.... coronary artery vein bypass grafting (cavbg)
See THROMBOSIS; VEINS, DISEASES OF.... deep vein thrombosis (dvt)
See telangiectasia.... broken veins
Veins are the blood vessels that convey blood back from the tissues towards the heart. Two common conditions that affect them are THROMBOSIS and varicosities (see below).
Varicose veins are dilated tortuous veins occurring in about 15 per cent of adults – women more than men. They most commonly occur in the legs but may also occur in the anal canal (HAEMORRHOIDS) and in the oesophagus (due to liver disease).
Normally blood ?ows from the subcutaneous tissues to the super?cial veins which drain via perforating veins into the deep veins of the leg. This ?ow, back towards the heart, is aided by valves within the veins. When these valves fail, increased pressure is exerted on the blood vessels leading to dilatations known as varicose veins.
Treatment is needed to prevent complications such as ulceration and bleeding, or for
cosmetic purposes. Treatment alternatives include injection with sclerosing agents to obliterate the lumen of the veins (sclerotherapy), or surgery; in the elderly or un?t, an elastic stocking may su?ce. One operation is the Trendelenburg operation in which the saphenous vein is disconnected from the femoral vein and individual varicose veins are avulsed. (See also VASCULITIS.)
Thrombosis Thrombosis occurs when blood, which is normally a liquid, clots within the vein to form a semisolid thrombus (clot). This occurs through a combination of reduced blood ?ow and hypercoagulability (a reduced threshold for clotting). The most common site for this to occur is in the deep veins of the leg, where it is known as a deep-vein thrombosis (DVT).
Predisposing factors include immobility (leading to reduced blood ?ow), such as during long journeys (e.g. plane ?ights) where there is little opportunity to stretch one’s legs; surgery (leading to temporary post-operative immobility and hypercoagulability of blood); oestrogen administration (low-dose oestrogen oral contraceptives carry a very low relative risk); and several medical illnesses such as heart failure, stroke and malignancy.
Deep-vein thrombosis presents as a tender, warm, red swelling of the calf. Diagnosis may be con?rmed by venogram (an X-ray taken following injection of contrast medium into the foot veins) or by ultrasound scanning looking for ?ow within the veins.
Prevention is important. This is why patients are mobilised and/or given leg exercises very soon after an operation, even major surgery. People should avoid sitting for long periods, particularly if the edge of the seat is hard, thus impeding venous return from the legs. Car drivers should stop regularly on a long journey and walk around; airline travellers should, where possible, walk round the aisle(s) and also exercise and massage their leg muscles, as well as drinking ample non-alcoholic ?uids.
Diagnosis and treatment are important because there is a risk that the clotted blood within the vein becomes dislodged and travels up the venous system to become lodged in the pulmonary arteries. This is known as PULMONARY EMBOLISM.
Treatment is directed at thinning the blood with ANTICOAGULANTS, initially with heparin and subsequently with WARFARIN for a period of time while the clot resolves.
Blocked super?cial veins are described as super?cial thrombophlebitis, which produces in?ammation over the vein. It responds to antiin?ammatory analgesics. Occasionally heparin and ANTIBIOTICS are required to treat associated thrombosis and infection.... veins, diseases of
Common disorders affecting veins include varicose veins, deep vein thrombosis (see thrombosis, deep vein), and thrombophlebitis.... veins, disorders of
two pairs of veins in the embryo that carry blood from the head (anterior cardinal veins) and trunk (posterior cardinal veins); they unite to form the common cardinal vein, which drains into the sinus venosus of the heart.... cardinal veins
the presence of thrombosis in the dural venous sinuses, which drain blood from the brain. Symptoms may include headache, abnormal vision, any of the symptoms of stroke (such as weakness of the face and limbs on one side of the body), and seizures. Treatment is with anticoagulants.... cerebral venous sinus thrombosis
(DBS) a surgical treatment involving the implantation of a medical device that sends electrical impulses to specific parts of the brain. DBS in selected brain regions can provide benefits for treatment-resistant movement disorders, such as Parkinson’s disease, tremor, and *dystonia.... deep brain stimulation
mechanical obstruction of labour in which the fetal head is unable to rotate from occipitotransverse to occipitoanterior position (see occiput).... deep transverse arrest
a group of veins within the skull that drain blood from the venous sinuses of the dura mater to veins outside the skull.... emissary veins
one of several short veins originating within the lobes of the liver as small branches, which unite to form the hepatic veins. These lead directly to the inferior vena cava, draining blood from the liver.... hepatic vein
the veins draining most of the blood from the lower limbs and pelvic region. The right and left common iliac veins unite to form the inferior vena cava. They are each formed by the union of the internal and external iliac veins.... iliac veins
(brachiocephalic vein) either of two veins, one on each side of the neck, formed by the junction of the external jugular and subclavian veins. The two veins join to form the superior vena cava.... innominate vein
a vein carrying oxygenated blood from the lung to the left atrium. See pulmonary circulation.... pulmonary vein
Health Encyclopedia