Embolism is a sudden closure of a blood vessel due to blockage by a moving object, thus an embolus. An embolus is usually a blood clot, but may also be a fat globule, air bubble or rarely amniotic fluid. A result of the obstruction of the blood vessels is ischemia and the tissue, which the blood vessel supplied, is pallid. Consequences of embolism can occur without any symptoms, but can also cause the patient's death.
Types of embolism
Embolism is a serious condition that is life-threatening. Therefore, it is important to first determine the cause of the resulting condition. According to the character of the clotting, or embolus, we can distinguish several types of embolism.
- The most common type of embolism is called thromboembolism, where the embolus is a blood clot that occurs mainly in the veins of the lower extremities and pelvis. It is dangerous because it can detach and be taken away by blood into the right side of the heart and the lungs, where due to its size, it can obstruct the pulmonary arteries. Blood clots can form also in the heart, if some parts do not contract properly, such as atrial fibrillation. Then, blood clots can tear off from the left atrium and by the left ventricle they are drifted into the systemic circulation. This blood clot can get into the brain and cause a stroke.
- Another type is fat embolism, which is caused by bone injury, blunt trauma of adipose tissue, or burns. Fat particles are not visible by the naked eye and can get stuck in the capillaries in the brain or kidneys.
- Air embolism occurs when air enters the peripheral veins, and it can due to physical laws prevent blood flow in the vessel. It can happen during operations when the air bubble gets into a peripheral vein through an introduced cannula. It also includes the so-called Caisson disease that is caused by rapid ascent during diving. Even small quantities of air can cause death.
- Amniotic fluid embolism is caused by complications during childbirth. It is a result of ingestion of amniotic fluid into the venous system of the uterus during childbirth and it consequently enters the lungs by blood.
- Foreign object embolism occurs when a foreign object enters the bloodstream. For example it can be a broken needle tip etc.
Symptoms of embolism
Symptoms of embolism are very various. In general, embolism of smaller embolus may be asymptomatic. But sometimes the consequences of embolism can be severe or even fatal. The symptoms mainly depend on the location of the embolism, i.e., whether it is in venous or arterial vessels.
- If the embolus is carried by veins most likely it will get to the heart and from the heart directly to the lungs, where it will get stuck and cause pulmonary embolism. The symptoms are chest pain, shortness of breath, pallor, sweating, increased heart and respiratory rate and expectoration of blood. Lung function may be damaged to such an extent that it leads to death.
- If the embolus is carried by arteries it may obstruct vessels in various organs, for example the brain and cause a stroke. Or it can block a blood vessel supplying oxygenated blood for the kidneys or intestines and cause a heart attack. An embolus may also prevent blood flow into a limb, causing its necrosis.
Risk factors of embolism
There are various risk factors that lead to embolism. The most vulnerable groups are immobile patients, then patients after surgery, especially of the legs. Also, vulnerable to embolism are patients with heart failure. A risk factor is the use of hormonal contraception.
Diagnosis of embolism
Diagnosis of embolism is based primarily on the use of imaging techniques. Pulmonary embolism caused by a blood clot can be best proved by using a CT-angiography. This is an invasive method in which it is necessary to introduce a catheter into a vein, a long tube through which a contrast agent is injected. Then, using computerized tomography we can construct an image that gives information about the exact location of the clogged blood vessel. In the case of fat or air lung embolism X-rays can be used, then for air embolism also echocardiography, i.e. ultrasound of the heart.
Treatment of embolism
Embolism may be asymptomatic, with mild or dramatic symptoms. It is a dangerous complication of trauma and operations. Doctors have a wide variety of treatment options, where they can pull out the embolus, dissolve it or effectively prevent its formation. Treatment of embolism is based on the type of the embolus.
- Treatment of thromboembolism is either thrombectomy, i.e. surgical removal of the blood clot from the blood vessel, or the use of anticoagulants, thus drugs decreasing blood clotting.
- Treatment of fat embolism includes corticosteroids, i.e. drugs based on steroid hormones and diuretics, which cause the secretion of fluids from the body. Also, oxygen therapy is an integral part of treatment.
- Treatment of air embolism includes inhalation of 100% oxygen, and if the air bubble is in the heart, it is necessary to lay the patient on the left side and his head down to avoid the introduction of air into the brain.
- Treatment of amniotic fluid embolism is not in any way specific and consists in the stabilization of breathing and blood circulation of the woman and a rapid cleaning of the uterus from amniotic fluid.