Definition
Blood clots are gel-like clumps of blood. When they form in response to a cut or other injury, they stop the bleeding by plugging the injured blood vessel. These blood clots help the body heal.
But some blood clots form inside the veins without a good reason. They don’t dissolve naturally. These clots may require medical attention, especially if they are in the legs, lungs or brain. A number of conditions can cause this type of blood clot.
Causes
Blood clots are made when substances in the blood thicken and form a semisolid mass. This process may be triggered by an injury. Sometimes it occurs inside blood vessels that don’t have an obvious injury.
Once these clots form, they can travel to other parts of the body where they can cause harm. There are a variety of factors and conditions that can cause troublesome blood clots, and there are some serious conditions that are associated with blood clots. These include:
Antiphospholipid syndrome
Arteriosclerosis / atherosclerosis
Cancer
Certain medications, such as oral contraceptives and hormone therapy drugs
Coronavirus disease 2019 (COVID-19)
Deep vein thrombosis (DVT)
Factor V Leiden
Family history of blood clots
Heart arrhythmia (heart rhythm problems)
Heart attack
Heart failure
Obesity
Peripheral artery disease (PAD)
Polycythemia vera
Pregnancy
Prolonged sitting or bed rest
Pulmonary embolism — a blood clot in an artery in the lung.
Smoking
Stroke
Surgery
