Deep Venous Thrombosis
Alternate Names : DVT, Economy Class Syndrome
Deep venous thrombosis, also called DVT, refers to a blood clot that has formed
in one of the large veins far below the skin.
What is going on in the body?
A deep venous thrombosis is most common in the legs, but it can occur in other
parts of the body. A blood clot in a vein blocks the normal flow of blood back
to the heart. It also causes the affected vein to become inflamed.
What are the causes and risks of the condition?
A deep venous thrombosis forms when a blood clot in a vein blocks the normal
flow of blood back to the heart. Circumstances that increase an individual's
risk of developing DVT include:
immobility that lasts more than 3 days
increased thickness of the blood, which may be inherited or acquired
injury or trauma
major surgery in the past 4 weeks, especially in the pelvis or abdomen
pregnancy, particularly right before and after delivery
Diseases and conditions that increase a person's risk for DVT
congestive heart failure
, a condition in which the weakened heart can't pump enough blood throughout
a history of blood clots, such as a pulmonary embolus or another DVT
nephrotic syndrome, a
sepsis, a bodywide
autoimmune disorder in which the body attacks its own tissues
a bowel disorder
Medicines that can increase the risk for DVT include:
illegal drugs taken intravenously
Injuries can also increase a person's risk for DVT. Common injuries
linked to DVT include:
bone fractures in the legs
multiple trauma, or significant injury
spinal cord injury
Recently, there have been conflicting research reports about the role of long
airplane flights in deep venous thrombosis. Some studies showed a relationship
between airline travel and an increase in the blood's tendency to form clots.
The researchers attributed the increased risk of clot formation to the low
pressure, low oxygen,
dehydration, and lack of activity on long flights. Another study
showed that individuals hospitalized with DVT were four times more likely to
have gone on a long trip recently than those treated at the hospital for other
conditions. Because of findings like this, deep venous thrombosis is often
referred to as "economy class syndrome."
researchers have not found the same relationship. Some suggest that only people
with a particular genetic abnormality are at risk for economy class syndrome.
More research is needed in this area.