Harvard Heart Letter

When a clot interferes with blood flow

Blood clots that form in the legs (deep-vein thrombosis) or lungs (pulmonary embolism) can be painful, and even deadly. Deep-vein thrombosis typically causes pain and swelling in the affected limb. The sensations are uncomfortable enough that most people are compelled to seek medical care. If the clot travels to the lungs, it can be fatal: 25% of people die before—or shortly after—they seek help. Prompt treatment and good follow-up can minimize the danger. The clot is treated with anticoagulants, first in the hospital, then at home. Once the clot is dissolved, attention turns to preventing another one from forming.
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