Blockage of an artery by an embolus (a fragment of material carried in the bloodstream). An embolus can consist of a variety of substances. It is often formed from a blood clot. Different substances that can form an embolism include a bubble of air or other gas; a tumour or piece of tissue; bone marrow, a clump of bacteria, cholesterol or fat; or, unusually, amniotic fluid forced into a woman’s circulation during childbirth.
A blood clot that has been broken off from a larger clot elsewhere in the circulation is the most known type of embolus.
Pulmonary embolism is a disorder that can be due to a blood clot. The condition is often the result of a fragment breaking off from a deep vein thrombosis and being carried by the heart to block an artery that is supplying the lungs. Pulmonary embolism can cause sudden death. Blood clots can form inside the heart after a heart attack, or in the atria (upper chambers of the heart) in atrial fibrillation and then travel to the brain. This then leads to a cerebral embolism, which is an important cause of stroke (damage to part of the brain due to an interruption to its blood supply).
Air embolism, in which a tiny artery is blocked by an air bubble, is uncommon. Fat embolism, in which a vessel is blocked by fat gobules, is a likely complication of a major fracture of a lib; it arises when fat is released from the marrow of the broken bone. Amniotic fluid embolism arises during labour, or immediately after delivery of the child. This unusual complication is usually fatal.
Symptoms of an embolism rely on the site of the embolus. Pulmonary embolism may lead to chest pains and breathlessness. If the embolus lodges in the brain, a stroke can take place, disturbing vision, speech or movement. If an embolism blocks an artery to the leg, the limb will become excruciating and turn pale. When left untreated, gangrene tissue death) can occur.
In extreme cases of fat embolism, heart and breathing rates rise extensively and there can be confusion, restlessness, and drowsiness.
If an extreme embolism causes the person to collapse, emergency life saving measures are undergone in order to maintain the circulation and breathing.
Embolectomy (surgical removal of the blockage) can be possible. If the embolus is created from a blood clot and surgery is not possible, thrombolytic drugs (drugs that dissolve blood clots) and anticoagulant drugs (drugs that prevent or stop clot formation) can be given.