Passage 20
Often people with deep vein thrombosis do not have any symptoms.In these people，this condition is usually suspected only after a blood clot is discovered in the lung.Once diagnosed with deep vein thrombosis，treatment begins if it is likely that the blood clot will grow or that a piece of the clot might break loose and flow to the lungs.
If you have a blood clot in your upper leg vein，you will usually need to take anticoagulant medication for 3 to 6 months，and possibly longer.After 3 to 6 months，your doctor may recommend that you continue Warfarin on an ongoing basis to prevent deep vein clots from recurring.Typically，if you have a blood clot in the lower deep leg veins，you will need to take anticoagulant medication for 6 to 12weeks fan monitor the blood clot with ultrasound.
The main goal of treatment is to prevent the blood clot from growing or moving to the lungs.If a blood clot in the deep veins of the leg breaks loose and travels to the lungs，it can cause pulmonary embolism.Pulmonary embolism occurs in 25%of cases of untreated，diagnosed deep leg vein thrombosis.In people who receive treatment for deep vein thrombosis，the rate of pulmonary embolism falls drastically.Blood clots in the lung occur more often in people with deep vein blood clots in the upper rather than the lower leg veins.Only about 20%of blood clots in the veins of the calf will become larger and extend into the upper leg or groin veins.Blood clots that extend into the upper leg veins usually require with anticoagulant medication to prevent pulmonary embolism.
The recurrence rate for deep vein thrombosis varies depending on what caused the blood clot and how it was treated.Recurrence is most common in people who havecontinuing risk factors such as cancer or inherited blood-clotting problems and in people who have hasd more than one blood clot in the leg.Recurrence is lowest in people who have a short-term risk factor，such as surgery or temporary inactivity.In 30%to 50%of people who have had deep vein thrombosis with symptoms，a condition calledpostthrombotic syndrome may develop within 8 years.This condition can cause pain，swelling，discoloration，and sores on the leg.
1.Once diagnosed with deep vein thrombosis，the patient will be given the treatment to____.
A.dissolve the existing blood clots
B.break loose the existing blood clots
C.prevent the new clots from forming
D.prevent the existing blood clots from growing and moving to the lungs
2.If a patient is found a clot in his lower deep leg vein，he will have to.
A.take anticoagulant medication for 3 to 6 months
B.monitor his blood clot with ultrasound with no need for medication
C.take anticoagulant medication for 6 to 12 weeks
D.need continuous use of Warfarin(https://www.daowen.com)
3.According to Paragraph 3，Pulmonary embolism is most likely to occur when.
A.blood clots are found in the upper leg veins
B.more than one blood clot is found in the leg
C.blood clots appear in the lower leg veins
D.proper treatment was given to patients with deep vein thrombosis
4.The recurrence rate for deep vein thrombosis may be the lowest among people.
A.who have had a family history of blood-clotting problems
B.who have been diagnosed with deep vein thrombosis after undergoing the mastectomy due to breast cancers
C.whose deep vein thrombosis are caused by temporary sedentary work
D.who have more than one clot in the leg
5.The author of this passage focuses on the____of deep vein thrombosis.
A.treatment
B.early diagnosis
C.treatment and prevention
D.treatment and prognosis