Wherever the embolism lodges, it blocks the flow of blood. The blockage deprives the tissues in that location of its normal blood flow and oxygen (ischemia). This can result in damage or destruction, even death of the tissues (necrosis), in that organ. A large embolism is a blood clot that originates in the heart. This clotting can occur when the heart’s chambers are pumping incorrectly—as in atrial fibrillation, cardiomyopathy, or after a heart attack. It can also occur when the inner wall of the heart has been damaged, such as after a heart attack or with heart valve disease disorder. Other emboli can form when there is an irregularity in the wall of a blood vessel (plaque) and the flow of blood in that area becomes turbulent and initiates the clot forming system.Arterial emboli may be caused by one embolus or multiple emboli. Risks include atrial fibrillation, because the blood flow through the atria can be slow enough to trigger clots to form, which can then travel (embolize).
Symptoms depend on the location of the embulous and the extent to which it blocks the flow of blood. An embolism in the brain that causes a stroke can result in some degree of brain damage. When an embolism blocks circulation in the arm or leg, the part of the limb below the blockage becomes cold, pale, weak, numb, and painful, and there is no pulse. Without treatment to restore circulation, the tissue dies and gangrene may set in. In nearly a quarter of the cases, amputation is necessary. When an embolism blocks blood flow to the eye, all or part of the vision in that eyes disappears. Blockage of arteries leading to the kidneys can cause kidney damage, high blood pressure, and blood in the urine. However, sometimes the blockage of the vessels is less severe because there are other vessels that can supply the tissue with blood.
