what are the symptoms of blood clots?

When a thrombus occupies more than 75% of surface area of the lumen of an artery, blood flow to the tissue supplied is reduced enough to cause symptoms because of decreased oxygen (hypoxia) and accumulation of metabolic products like lactic acid. More than 90% obstruction can result in anoxia, the complete deprivation of oxygen, and infarction, a mode of cell death.
Cerebral thrombosis (blood clot in the main cerebral artery of the brain) may cause stroke.
Coronary thrombosis (blood clot in the coronary artery) may cause heart attack.
Deep vein thrombosis may cause pulmonary embolism.
Symptoms will differ according to the location of the blood clot in the various organs of the body.

What are the symptoms of blood clots?

Venous clots do not allow blood to return to the heart and symptoms occur because of this damming effect. Most often occurring in the legs or the arms, symptoms include:

•swelling,

•warmth,

•redness, and

•pain.
Arterial clots do not allow blood get to the affected area.

•Pain is the initial symptom of this ischemia, or oxygen deprivation due to loss of blood supply.

•Other symptoms depend upon the location of the clot, and often the effect will be a loss of function. Heart attack and stroke are self-explanatory.

•In an arm or leg, in addition to pain, the limb may appear white, and weakness, loss of sensation, or paralysis may occur.

•If the blood supply is lost to an area of the bowel, in addition to intense pain, there may be bloody diarrhea.