Deep Vein Thrombosis

This text is a supplement to the more general article about venous diseases of lower limbs, which I recommend to read as well. The deep vein thrombosis of the lower extremities is a very common problem. It is an uncomfortable and painful condition, which also threatens the patient with pulmonary embolism.


The causes of the disease are identical to general causes of blood clots (thrombi) formation. To understand the specifics of deep vein thrombosis, it is necessary to say something about the venous system of the lower limbs.


The blood from the lower extremities flows through two venous systems – the deep system and the superficial system. Both systems are interconnected with special perforating veins. The connecting veins are able to ensure only one-way blood flow from the surface system into the deep one. The leg veins are equipped with special valves. Under normal circumstances, the movement of leg muscles pushes blood towards the trunk the valves prevent the blood from returning.


The common risk factors for development of deep veins thrombosis include leg injuries with subsequent long-term immobility of the lower extremities (especially having the leg in a plaster cast), obesity, pregnancy, conditions after major surgeries, hormonal contraception, chronic venous insufficiency and thrombophilia (e.g. hyperhomocysteinemia, Factor V Leiden, etc). It must be also noted that the deep vein thrombosis may be the first manifestation of a previously unknown malignant disease.


The deep vein thrombosis means formation of a thrombus in the deep venous system of a lower extremity. The blood accumulates and under pressure it tries to flow to the surface veins that expand with blood. The affected limb is reddish, swollen and painful on touch. It is important to know that this affection is usually only unilateral and bilateral thrombosis is much less common. Sometimes, the first manifestation of a deep vein thrombosis is the pulmonary embolism.


As always, it is necessary to evaluate the clinical symptoms and perform physical examination of the affected leg. The presence of a thrombosis can be verified by an ultrasound, which allows us to see the entire venous system and any blood clots.


It is advisable to strengthen the veins of the lower extremities by regular physical exercise and prevent long-time immobilization. When a girl is prescribed hormonal contraception, the doctor should ask about any case of deep vein thrombosis in the family and try to diagnose any clear cases of thrombophilias. In addition, the users of hormonal contraception should not smoke as it significantly increases the risk of thrombosis. People admitted to hospitals, immobilized patients and patients after surgical interventions affecting the lower extremities are usually preventively administered small doses of anticoagulants such as the LMWH.


The patient should wear elastic bandages. The only effective therapy is regular administration of anticoagulants in therapeutic doses. The most used are LMWH and warfarin, but new drugs are being gradually introduced.


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Sources: basic text sources