Embolism: Symptoms, Prevention & Best Treatment

In the case of an embolism, what is known as an embolus (eg blood clot, fat, cells or air) occludes a blood vessel. Depending on the part of the body in which the embolism occurs, there are various symptoms such as severe pain or paralysis. Embolisms are sometimes life-threatening because they lead to a heart attack or stroke, among other things. Read more about the definition, causes, signs and therapy here!

ICD codes for embolism: I82 | O88 | I26 | I28 | T79 | I74I27

Quick overview

• What is an embolism? Complete or partial blockage of a blood vessel by endogenous or foreign material (e.g. blood clot) entering the bloodstream.

• Symptoms: Depending on which blood vessel is affected, different symptoms develop. Sudden pain often occurs; sometimes those affected are symptom-free.

• Causes: A blood clot (thrombus) that detaches from the vessel wall and enters the bloodstream is often the trigger for an embolism (thromboembolism).

• Treatment: The doctor usually treats an embolism with medication, in some cases also with surgery. The goal of therapy is to dissolve or remove the embolus.

• Prevention: exercise regularly, drink enough, avoid being overweight, stop smoking; if necessary, thrombosis prophylaxis, e.g. after operations (anticoagulant medication, compression stockings).

• Diagnosis: Discussion with the doctor, physical examination (including ultrasound, CT, MRI, angiography).

What is an embolism?

The term embolism comes from the Greek (“embolla”) and means “to throw in”. In the case of an embolism, a plug (“embolus” = vascular plug, plural “emboli”), which is washed in via the blood, blocks a blood vessel. It prevents the blood from flowing freely through the vessel.

As a result, the affected area is no longer sufficiently supplied with oxygen and important nutrients. Over time, the tissue there dies, and the consequences can be life-threatening, such as a heart attack or stroke.

An embolus will only cause an embolism if its diameter is larger than that of the blood vessel.

What types of embolism are there?

An embolism develops in those affected both in the veins and in the arteries. Likewise, emboli form in both blood vessels. Doctors therefore differentiate between arterial and venous embolisms.

Arterial embolism

In an arterial embolism, the embolus usually comes from the left atrium of the heart or a large artery (arterioembolic embolus), such as the main artery (aorta) or pulmonary artery (pulmonary artery). An embolus often blocks a vessel to the brain (cerebral embolism), to the arms or legs (arm or leg embolism) or to organs such as the intestines, kidneys or spleen (intestinal, kidney or splenic infarction). In most cases, an arterial embolism gets an embolus into the brain (cerebral embolism) and triggers a stroke there.

Affect arterial embolism

  • About 60 percent the brain.
  • About 28 percent the legs.
  • About 6 percent the arms.
  • About 6 percent the organs (e.g. intestine, kidneys, spleen).

Venous embolism

In the case of a venous embolism, the vascular plug forms in the veins – preferably in the legs or pelvis. It travels through the right ventricle and pulmonary artery to the lungs, where it often causes a pulmonary embolism.

Paradoxical embolism

The paradoxical embolism – also crossed embolism – is a special form of embolism. The embolus forms in a vein and blocks an artery (but not the pulmonary arteries!). This is only possible if the embolus enters the left ventricle through gaps or small openings in the cardiac septum (e.g. due to a congenital heart defect). This means that the embolus does not go to the lungs as in a conventional venous embolism, but rather to the arterial system of the bloodstream.

How does an embolism differ from a thrombosis?

In a thrombosis, a blood clot (thrombus) blocks a blood vessel right where it forms. By definition, an embolism does not occur where an embolus forms. In some cases, however, a thrombus develops into an embolus.

The thrombus detaches from the inner wall of the vessel where it originated and moves through the body via the bloodstream. If this delayed plug (“embolus”) blocks a vessel elsewhere in the body, doctors speak of an embolism (or thromboembolism).

What are signs of an embolism?

Embolisms cause very different symptoms depending on where they occur in the body. While some don’t make themselves felt at all, others lead to numerous ailments and omens. Basically, people with an embolism have severe pain that occurs suddenly. The embolus disrupts the blood supply, causing the affected organ to stop functioning properly. In some cases, the tissue in the affected area even dies.

However, in some parts of the body that have good bypass circulation (collaterals) and supply the affected area with other vessels, it is also possible for people with a small embolism to have no symptoms.

Embolism in legs or arms

Embolism in legs or arms

If an embolism develops in a large artery in the leg or arm, the symptoms are usually very typical. They can be characterized by the “6P” (according to Pratt; six physical signs):

  • Pain.
  • Paleness.
  • Paresthesia.
  • Pulselessness.
  • Paralysis.
  • Prostation (shock).

In severe cases, an embolism in the arm or leg can result in the person being unable to move their arm or leg.

Embolism in the lungs

Embolism in the lungs

A pulmonary embolism manifests itself through pain in the lungs, sudden shortness of breath (dyspnea), accelerated breathing (tachypnea), palpitations (tachycardia), a feeling of anxiety, an acute drop in blood pressure (hypotension) and circulatory shock. If large enough, an embolus in the lungs will overload the heart and cause death.

Embolism in the brain

A cerebral embolism triggers a stroke. This manifests itself in those affected, for example, by paralysis (often on one side of the body), speech disorders and disturbances of consciousness.

Embolism in the heart

In rare cases, an embolus blocks the coronary arteries and triggers a heart attack in those affected. In some severe cases, an embolism in the heart leads to heart failure.

Embolism in the internal organs

An embolism in the area of the internal organs triggers various symptoms depending on the organ affected:


If the kidneys are affected by an embolism, this often leads to a renal infarction. Those affected then usually have severe pain in the lumbar region and blood in the urine (hematuria). In extreme cases, the kidney function fails completely (kidney failure).


A blockage in the spleen causes a splenic infarction. Typical signs are sudden pain in the left upper abdomen and pain in the left shoulder. The chest of those affected usually rises and falls noticeably less when they breathe. Sometimes you can hear rubbing noises in the area of the spleen when you breathe (perisplenic rubbing). In severe cases, the spleen fails to function.


In the intestinal mesentery – the band of connective tissue that attaches the intestines to the abdomen and in which the blood vessels and nerves run to the intestines (called the mesentery) – an embolism causes severe abdominal pain in those affected. They also often have bloody diarrhea and fever. Bowel movements are also often reduced or completely absent. In extreme cases, the affected section of the intestine dies.

The larger the area that the embolism cuts off from blood supply, the more severe the symptoms tend to be.

What leads to an embolism?

There are different causes of an embolism. The embolus that blocks the vessel and thus triggers an embolism usually consists of endogenous substances such as fat droplets, amniotic fluid, blood clots (thrombi) or air bubbles. In some cases, it also consists of foreign materials such as foreign bodies (e.g. parts of a hollow needle) or parasites (e.g. tapeworms).

Emboli can therefore be divided into:

  • Solid emboli consisting of, for example, blood clots, tissue, parasites or tumor cells.
  • Liquid emboli consisting of drops of fat or amniotic fluid, for example.
  • Gaseous emboli consisting of air bubbles, for example.

Depending on the cause, the following embolisms can be distinguished:


The most common form of embolism is thromboembolism. It is caused by a blood clot (thrombus) that detaches from the vessel wall and enters the bloodstream. This embolus then travels through the body with the bloodstream until it gets stuck somewhere and occludes a vessel. thromboembolism occurs.

Doctors distinguish between venous and arterial thromboembolism.

Venous thromboembolism (VTE)

In a venous thromboembolism, the embolus comes from a vein. It often forms in the veins of the pelvis or legs (eg, venous thrombus in the leg). This often occurs when those affected sit or lie down for too long and therefore the blood no longer circulates properly. This causes the blood to stagnate in some cases. A blood clot (thrombus) forms, which impedes the blood supply at this point and, in extreme cases, completely occludes the vessel. This may also be the case if those affected do not drink enough fluids (exsiccosis).

The risk of venous thromboembolism is increased if someone is bedridden (eg people in need of care), after an operation (eg if one lies down a lot afterwards) or if the person concerned has an inflammation of the veins (thrombophlebitis).

Arterial thromboembolism (ATE)

In an arterial thromboembolism, the embolus originates from an artery. It usually occurs in the left side of the heart. When the embolus detaches, it often travels to the brain (cerebral embolism) and triggers a stroke.

Arterial thromboembolism is the most common cause of heart disease, at up to 90 percent. These include, for example:

  • Atherosclerosis (“hardening of the arteries”); the blood vessels narrow due to deposits of blood components (e.g. cholesterol, white blood cells).
  • An injury or scarring of the inner lining of vessels (endothelium).
  • Coagulation disorders (thrombophilia).
  • Inflammation of the inner lining of the heart (endocarditis).
  • Expansion of the heart wall (aneurysm).
  • Atrial fibrillation; the heart beats irregularly too fast or too slow.

The most common embolisms are thromboembolism that occurs after thrombosis of the deep veins of the leg (pulmonary embolism) and thromboembolism in the arteries of the brain (stroke).

Tumor embolism

A tumor embolism is caused by carried cancer cells (tumor cells) or carried cancer tissue. As a result of the embolus (or the so-called metastatic embolus), it is possible for secondary tumors to form in other areas of the body.

Tumor embolisms are common in people with advanced cancers. The reason for this is that cancer increases the clotting ability of the blood. This means the blood clots faster. The more aggressive the cancer growth, the higher the risk of thrombosis and subsequently embolism.

Fat embolism

A fat embolism is an embolism caused by fat droplets in the bloodstream. A fat embolism often occurs after bone fractures (especially fractures of long bones such as the ribs) when the bone marrow is also damaged. This consists, among other things, of fat, which sometimes leaks out in the event of an injury and enters the bloodstream. Other causes of fat embolism include: blunt injuries (eg, contusion), burns, fatty liver, or surgery such as amputation or bone marrow transplant. Most often, a fat embolism forms in the blood vessels of the lungs (pulmonary fat embolism).

Bone marrow embolism

In the case of broken bones (fractures), in some cases tissue from the bone marrow gets into the vascular system and triggers an embolism there. This type of embolism therefore often occurs in fractures of long bones in which bone marrow is located. These include, for example, the upper arm bone (humerus), the forearm bones ulna and radius (radius) and the thigh bone (femur).

Bacterial embolism (septic embolism)

In a bacterial embolism, bacteria enter the bloodstream and cause an embolism. This happens, for example, as a result of blood poisoning (sepsis) or inflammation of the inner lining of the heart (endocarditis). A septic embolus can lead to a purulent infection of the affected tissue.

In contrast to the septic embolus, a so-called blander embolus is not bacterially infected.

Gas embolism

A gas embolism occurs when gas bubbles enter the bloodstream and narrow or block the vessel. If the gas is air, it is called an air embolism. A gas embolism can occur, for example, when a medium-sized or large blood vessel is injured (eg, the superior vena cava), when air is introduced into a blood vessel (air insufflation), or through a ruptured lung (pulmonary rupture).

A life-threatening gas embolism can also occur in the event of a so-called decompression accident (decompression sickness). Gas bubbles form in the blood vessels if the external pressure drops too quickly. This can happen, for example, when you emerge from the water too quickly (diving sickness) or when you ascend too quickly.

Amniotic fluid embolism

Amniotic fluid embolism (also known as “obstetric shock syndrome”) occurs if amniotic fluid enters the mother’s bloodstream via the uterus during childbirth. It is a rare but life-threatening complication of childbirth that often results in brain damage in both mothers and children. The exact cause of an amniotic fluid embolism has not yet been clearly clarified.

Parasitic embolism

In a parasitic embolism, parasites block the vessel. These are often tapeworm larvae that get into the gastrointestinal tract. There they pierce the intestinal wall and get into the blood.

Foreign body embolism

In a foreign body embolism, foreign bodies enter the bloodstream. This is the case, for example, if parts of examination tools such as catheters (tubes that are inserted into organs) or cannulas (hollow needles) break off during an examination and get into the bloodstream. Other foreign bodies include shrapnel or shot.

What are risk factors for an embolism?

There are some factors that increase the risk of an embolism. One of the most important risk factors for thromboembolism is, for example, heart disease – especially atrial fibrillation, in which blood clots form in the heart atria. Risk factors are also:

In principle, the same risk factors apply to embolism as to thrombosis.

What can you do about an embolism?

The aim of therapy for an embolism is to ensure that sufficient blood flows through the blocked vessel again. For this purpose, doctors administer anticoagulant drugs. In severe cases, the blood clot is dissolved with drugs (drug thrombolysis) or surgically removed (embolectomy).


In the case of an embolism, especially a pulmonary embolism, prompt medical treatment is important. The doctor administers anticoagulants (anticoagulants, eg heparin) to the patient as an injection or infusion. They ensure that the embolus does not enlarge and that no new blood clots form.

In severe cases, the blood clot is dissolved with medication. For this purpose, the doctors administer so-called fibrinolytics (medicinal thrombolysis).

In order to prevent another thromboembolism, the patient is then given anticoagulant medication in tablet form (e.g. so-called DOAK or vitamin K antagonists such as phenprocoumon) for several months. This is called oral anticoagulation, roughly translated as “blood clotting inhibition by medication”. The anticoagulant drugs are effective but carry some risk of bleeding. Some patients therefore receive acetylsalicylic acid (eg ASA 100 mg) as long-term therapy to prevent blood clots and at the same time to keep the risk of bleeding low.

Removal of the embolus using a catheter

If drug-based thrombolysis is not possible, doctors remove the blood clot with the help of a catheter. You gently push the catheter through a vein to the blocked blood vessel. They dissolve the embolus with small instruments or a drug (thrombolytic), which they insert into the catheter.

Surgery (embolectomy)

The last option to remove the blood clot is what is known as a surgical embolectomy. The doctors remove the embolus in an open operation. In the case of a pulmonary embolism, the patient is put under general anesthesia and connected to a heart-lung machine.

How can you prevent an embolism?

If you want to prevent an embolism, it is important that you minimize the risk by doing the following:

Lifestyle changes

  • If you are a smoker, stop smoking.
  • Avoid being overweight and eat a balanced diet.
  • Drink enough fluids (at least one and a half to two liters a day).
  • Make sure you exercise regularly on long flights or car journeys.
  • Go to regular check-ups with your family doctor to have diseases such as high blood pressure or diabetes mellitus recognized and treated at an early stage.
  • After an operation, get up as soon as possible after consultation with the doctor treating you and get enough exercise.

Prevent thrombosis

Because any injury blood clotting, operations also increase the risk of thrombosis or embolism. Childbirth also increases the risk of thrombosis or embolism in pregnant women. Doctors therefore often prescribe heparin injections after surgery or childbirth, which those affected usually inject themselves under the skin once a day. Heparin inhibits blood clotting and thus prevents thrombosis and embolism.

To prevent an embolism, the doctor also often prescribes compression stockings (“thrombosis stockings”). As a rule, those affected put on these stockings in the morning after getting up and take them off again in the evening before going to bed. They can also be worn continuously. Compression stockings support better blood flow in the leg and thus prevent thrombosis.

The duration of this thrombosis prophylaxis depends on the individual risk.

In the case of certain diseases (e.g. severe circulatory disorders in the arteries), those affected are usually not allowed to wear compression stockings. Therefore, ask your doctor beforehand whether thrombosis stockings are suitable for you.

How does the doctor diagnose an embolism?

The first point of contact if an embolism is suspected is the general practitioner. If he suspects an embolism behind the symptoms, he usually refers the person concerned to a hospital. There, a specialist in internal medicine (internist) specializing in vascular diseases (angiologist or phlebologist) treats the person concerned.

An embolism is often life-threatening. It is therefore important that the doctor immediately clarifies symptoms that indicate an embolism and acts accordingly.

Interview with the doctor and physical examination

Since the symptoms of an embolism are sometimes ambiguous, it is important for the doctor to examine the patient closely. To do this, he first conducts a detailed discussion (anamnesis) with the person concerned. For example, he asks him about the symptoms and whether he has recently had an operation or whether he has had a blood clot before. He then performs a physical exam on him. This often provides clues to the diagnosis. If, for example, the doctor not only notices sudden pain and pale skin, but also a missing pulse and vascular noises in the arms or legs, this is already a clear indication of an embolism in the arm or leg.

Blood test

A blood test is also part of the diagnosis of an embolism. Certain blood values confirm the suspicion of an embolism. These include the so-called D-dimers. D-dimers are proteins that are formed when a blood clot breaks down. If they are elevated, this is an indication that a blood clot, i.e. a thrombosis or embolism, is being broken down somewhere in the body.

Ultrasound, CT, MRI

If the examination confirms the suspicion of an embolism, the doctor carries out an imaging examination, for example using ultrasound (sonography), computed tomography (CT) or magnetic resonance imaging (MRI).

During an ultrasound examination of the vessels (color duplex sonography), the doctor can see, for example, whether the vessel wall is narrowed. He also uses ultrasound to determine the direction in which the blood is flowing in the vessels and how fast the blood is flowing through the vessels (flow rate). The latter gives the doctor information about whether there are constrictions or blockages in the vessels.


With the help of computer tomography or magnetic resonance imaging, the doctor creates images of the vessels and the vascular system (so-called CT angiography or MRI angiography). To do this, the doctor injects a contrast agent (an iodine-containing, water-clear and colorless liquid that can be seen on an X-ray) into the blood vessel and then carries out computed tomography or magnetic resonance imaging. The interior of the vessel is then visible in the CT or MRT image. In this way, the doctor can tell whether an embolus is blocking a vessel or whether the artery wall has changed (eg narrowed) due to other causes such as arteriosclerosis (hardening of the arteries).


If an embolism in the lungs is suspected, a nuclear medical examination, the lung scintigraphy, makes sense. The examination consists of two parts: First, the doctor examines the ventilation of the lungs. The patient must inhale a weakly radioactively labeled gas. In this way, the distribution of activity in the lungs is measured.

The doctor then examines the blood flow in the lungs. To do this, he injects weakly radioactive protein particles into a vein in the patient. These reach the lungs with the bloodstream, where they get stuck in some of the finest blood vessels. The doctor uses a special camera (gamma camera, SPECT) to make these visible and take pictures. He can see where the blood flow is reduced by the blood clot.

Dr. Ashwani Kumar is highly skilled and experienced in treating major and minor general medicine diseases.