Deep Vein Thrombosis

6 mins read

Introduction
Deep vein thrombosis (DVT) is the formation of a blood clot (thrombus) in the deep leg vein. This condition is very serious as it can cause permanent damage to the leg which is known as post-thrombotic syndrome or pulmonary embolism.

In DVT, the flow of blood in vein is partially or completely blocked by the blood clot. DVT most commonly occurs in calf vein while thigh vein is affected less. Other deep veins in the body can be rarely blocked by blood clots.

Venous thromboembolism (VTE) refers to a group of problems, including DVT.

Causes

  • Immobility results in slow blood flow which is more likely to get clot than normal-flowing blood.
  • A surgical operation taking over 1-1.5 hoursis the most common cause of a DVT.
  • Illness or injury resulting in immobilityincreases the risk.
  • Long journeys.
  • Damage to inner lining of veinincreases the risk of a blood clot formation.
  • Inherited blood disorder that causes DVTs is a factor V Leiden mutation. Risk of DVT increases if you have a family history of DVTs – that is, a close relative who has had one.
  • Cancer or heart failure patientshave an increased risk.
  • Old people (above 60 years of age)are more likely to have a DVT.
  • Pregnancyincreases the risk. 1 out of 1,000 pregnant women have a DVT when they are pregnant or they have within about six months after they give birth.
  • Obesity also increases the risk.

Epidemiology
The exact incidence of DVT is unknown because most studies are limited by the inherent inaccuracy of clinical diagnosis. Existing data suggest that about 80 cases per 100,000 population occur annually, probably underestimate the true incidence of DVT. Approximately 1 person in 20 develops a DVT in the course of his or her lifetime.

Incidence is increased 4-fold in elderly persons. In hospitalized patients, the occurrence of venous thrombosis is very high and varies from 20-70%.

Prevalence by Sex
The ratio of male-to-female is 1.2:1, indicating males have a higher risk of DVT than females.

Prevalence by Race
From demographic point of view, Asian and Hispanic populations have a lower risk of VTE, whereas blacks and whites have higher risk of VTE.

Symptoms

  • Discoloration of the legs
  • Calf or leg pain or tenderness
  • Swelling of the leg or lower limb
  • Warm skin
  • Surface veins become more visible
  • Leg fatigue

Diagnosis
The following tests often done first to diagnose a DVT are:

  • D-dimer blood test- It detects fragments of breakdown products of a blood clot. Higher is the level, more likely is to have a blood clot in a vein. However, this test can be positive in some other situations also, such as in case of recent surgery or pregnancy.
  • Doppler ultrasound- used to show flow of blood in the leg veins, and any blockage in flow of blood. It is useful because it is an easy and non-invasive test.

Some blood tests may be done to check if you have an increased chance of blood clotting which includes the following:

  • Activated protein C
  • Antithrombin levels
  • Antiphospholipid antibodies
  • Complete Blood Count (CBC)
  • Lupus anticoagulant
  • Protein C and protein S levels

Treatment
Anticoagulants are given. This will keep more clots from forming or old ones from getting bigger.

Heparin is normally the first drug you receive.

  • Heparin is given through a vein (IV)
  • Newer forms of heparin can be given once or twice a dayby injection under the skin. For newer form of heparin, you may not need to stay in the hospital as long, or not at all.

On basis of medical history, fondaparinux may be recommended by doctor as an alternative to heparin.

A blood-thinning drug, for example warfarin (Coumadin), is usually started along with heparin.

  • Warfarin is taken by mouth. It takes several days to fully work.
  • Heparin is not stopped until warfarin has been at the right dose for at least 2 days.
  • Warfarin is most likely to be taken for at least 3 months. Depending on the risk for another clot, some people must take it longer, or even for rest of their lives.

Wearing Pressure Stockings improves blood flow in your legs and reduces the risk for complications from blood clots.

Surgery
In rare cases, surgery is required in case the medications do not produce the required effect. It involves:

  • Placement of a filter in largest vein of body to prevent blood clots from traveling to the lungs.
  • Injecting clot-busting medicines or removing a large blood clot from the vein.

Complication
Major complication of deep vein thrombosis is pulmonary embolism. It is a life-threatening conditionwith chest pain and breathing shortness. Most often it arises from legs.

Post-phlebitic syndrome can occur after a deep vein thrombosis. The syndrome is characterized by swollen leg with pain, and change in skin color and ulcer formation around the foot and ankle.

Prevention

  • Wear the pressure stockings.
  • Moving the legs often during long plane trips, car trips, and other situations in which you are sitting or lying down for long periods.
  • Blood thinning medicines as prescribed by physician.
  • Do not smoke.

Conclusion
The main cause of DVT is immobility – especially during or after surgery. The most serious complication is pulmonary embolus, in which part of the blood clot breaks off and the clot travels to the lung. With treatment, the risk of the above complication is much reduced. Treatment includes intake of anticoagulants (usually with warfarin), compression stockings, elevating the legs, and remain active.

Read More:
Did You Know About These 4 Natural Anti-Coagulants?
Your Oral Contraceptive Pill Could Give You A Fatal Blood Clot
Science Says: New Contraceptive Pills Linked To Increased Risk Of Blood Clots
References
1. Aeger K. The interpretation of signs and symptoms.Angiology. Apr 1969;20(4):219-23

2. Mclachlin J, Richards T, Paterson JC. An evaluation of clinical signs in the diagnosis of venous thrombosis. Arch Surg. Nov 1962;85:738-44.

3. Meignan M, Rosso J, Gauthier H, Brunengo F, Claudel S, Sagnard L, et al. Systematic lung scans reveal a high frequency of silent pulmonary embolism in patients with proximal deep venous thrombosis. Arch Intern Med. Jan 24 2000;160(2):159-64.

4. Kearon C. Initial treatment of venous thromboembolism. Aug 1999;82(2):887-91.

5. Kistner RL, Ball JJ, Nordyke RA, Freeman GC. Incidence of pulmonary embolism in the course of thrombophlebitis of the lower extremities. Am J Surg. Aug 1972;124(2):169-76.

6. Weitz JI, Middeldorp S, Geerts W, Heit JA. Thrombophilia and new anticoagulant drugs. Hematology Am SocHematolEduc Program. 2004;424-38.

7. Ginsberg J. Peripheral venous disease. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 81.

8. Guyatt GH, Akl EA, Crowther M, et al. Executive Summary: Antithrombotic Therapy and Prevention of Thrombosis. 9th ed. American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.Chest. 2012;141:7s-47s.

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