Thrombosis (venous, cerebral): see what it is, causes and symptoms


What is thrombosis?

Thrombosis (also called thromboembolism ) is a disease caused by the presence of blood clots within a vein or artery. It can be caused by inflammation, injury, physical inactivity, obesity , clot diseases and other conditions.

This change can be extremely dangerous. The clot, which is called a thrombus , can prevent total or partial blood from passing through the vein or artery (which is called an embolism ), or a piece of it can be carried through the bloodstream to the brain or heart, where it can cause the patient’s death by blocking the blood.

It is possible to develop a few different types of thrombosis, but the most common is venous thrombosis, which forms in veins. Veins are the part of the circulatory system that carries blood to the heart. Most of the time (the only exception being the pulmonary veins), this blood is venous, that is, it has little oxygen and a lot of carbon dioxide.

The veins carry this blood to the heart, which then pumps it to the lungs through the pulmonary arteries (the only arteries that carry venous blood, the rest takes oxygenated blood, also called arterial) to the lungs, so that carbon dioxide is released and oxygen absorbed.

After that, the blood goes to the arteries, which carry the blood out of the heart, which is rich in oxygen and goes to the cells of the body.

Thrombosis and thrombophlebitis are often associated, but they are not quite the same. Phlebitis is an inflammation of the vein. Thrombosis is a clot in any part of the vascular system.

A thrombophlebitis is then a clot accompanied by inflammation. It is possible that a thrombosis can cause phlebitis, and phlebitis can cause thrombosis.

  1. What is thrombosis?
  2. Types of thrombosis
  3. Causes of thrombosis
  4. Groups and risk factors
  5. Symptoms of thrombosis
  6. How is the diagnosis of thrombosis made?
  7. Can thrombosis be cured?
  8. What is the treatment for thrombosis?
  9. Medications for thrombosis
  10. Living with thrombosis
  11. Prognosis
  12. Complications of thrombosis
  13. How to prevent thrombosis?
  14. Common questions

Types of thrombosis

There are two major types of thrombosis that are divided into subtypes. They can be classified as venous thrombosis and arterial thrombosis . The venous is the most common and occurs when the thrombus is located in the veins, while the arterial occurs when the clot is in an artery. Both are more common in the lower limbs, the legs.

Venous thrombosis

Venous thrombosis is the most common type of the disease and occurs when blood clots in a vein. It has several causes and leads to pain and swelling, and can block the vein. If the thrombus detaches, it can reach the heart or lungs.

Deep vein thrombosis

Deep vein thrombosis is the most well-known type of the disease. It happens when the affected vein is one of the so-called deep veins , which are inside the muscles or organs.

Deep venous thrombosis is a serious condition and medical attention is urgently needed, because in addition to blocking the vein where it is located, it does not cause much inflammation, causing the thrombi to loosen easily, which increases the risk of they get stuck elsewhere.

Superficial venous thrombosis

Superficial venous thrombosis occurs when the affected vein is on the outside of the muscles, below the skin. It is common to develop from phlebitis, an inflammation of the vein, which in turn is common in varicose veins, which are dilated or twisted veins.

Unlike deep vein thrombosis, the superficial one has the tendency to cause a rapid inflammatory process, making the symptoms appear quickly and the detection easier, in addition to firming the clot in place, reducing the possibility of it detaching and going to another place on the body.

Arterial thrombosis

Arterial thrombosis is more rare, but like venous thrombosis, it usually affects the legs.

Some of the arterial thromboses are known and specific enough to have proper names. This is the case of cerebral thrombosis, which causes the blockage of an artery in the brain, characterizing an ischemic stroke , or pulmonary thrombosis, which when blocking an artery in the lungs is called pulmonary embolism .

Both diseases, as well as most arterial thrombosis, occur due to the release of clots from venous thrombosis. This is because the veins have a blood flow with less pressure, as well as valves to prevent the blood from returning, which is not necessary in the arteries.

This slows down the movement of blood and gives space for it to stop its course for a longer time, making the veins much more suitable than arteries for blood clotting.

Causes of thrombosis

Clots usually appear when blood flow is slow, which facilitates clotting.

In general, they can occur due to positions or immobilizations that cause reduced circulation or when there is a disease that causes the blood to clot faster. Several situations can cause this to happen, such as:


Phlebitis are inflammations in the walls of the veins, making them rigid and facilitating the adherence of lipids (fat), which in turn facilitate the coagulation of the blood around them.

Coagulated blood becomes a thrombus, causing a thrombosis – or, in this case, a thrombophlebitis.

Thrombi can loosen, being carried to other parts of the circulatory system and causing more thrombosis, in addition to being able to block blood flow in organs such as the heart and lungs.

However, the opposite can also happen. The formation of a thrombus can lead to inflammation of the vein, causing a thrombophlebitis that starts with thrombosis.


The arteriosclerosis is a lesion in arteries , which can progress to pectoris , which is a disease that reduces blood flow to the heart, causing chest pain . During evolution, atherosclerosis can lead to the formation of clots, causing arterial thrombosis.

Long sitting

Sitting can make it difficult for blood to flow from your legs, especially around your thighs. When someone sits for a long time, this reduction in blood flow can cause the formation of thrombi, causing a thrombosis in the legs.

Varicose veins

Varicose veins are superficial veins, just below the skin, that twist or dilate. This means that the valves that prevent the blood from going in the wrong direction do not close properly.

Thus, varicose veins can reduce the speed of circulation, allowing the venous blood to go the wrong way between one heart beat and another. This facilitates blood clotting in varicose veins, causing thrombi and, consequently, thrombosis.


Tumors can compress veins and arteries as they grow, causing blood flow to be reduced in the region. This reduction can lead to the formation of clots, causing a thrombosis.


Infections near or in the veins or arteries can lead to inflammation in the region or even directly to the formation of clots, causing thrombosis.

Certain medications

Several medications are capable of modifying blood clotting factors, so it is always important that your doctor has knowledge about which medications you take.

Groups and risk factors

Some people are more likely to develop thrombosis. In the group at risk for the disease are:


Tobacco is a major risk factor for thrombosis and for several reasons. One is that smoking increases the chances of phlebitis, which can cause thrombosis.

Another factor is that the substance affects circulation in order to facilitate blood clotting within the circulatory system.

Read more: What is Smoking, treatment and diseases caused by smoking


Pregnancy increases the chances of developing thrombosis, despite the considerable increase in risk, usually if there is a family history of thrombosis.

This is because the baby makes the veins in the legs and pelvis suffer with more pressure, which can lead to less circulation and blood clotting. In addition, the entire pregnancy process causes blood changes ranging from the composition of the blood to the integrity of the vessels.

Hormonal contraceptives

The use of hormone-based contraceptives is related to thrombosis, both venous and arterial, at different levels (the more estrogen in the medication, the greater the risks).

In some cases, the risk can be up to 6 times higher compared to women who do not use contraceptives.

In addition, Anvisa points out that certain contraceptives such as those containing drospirenone, gestodene or desogestrel increase the chances of developing vein blockage by thrombi by up to 6 times.

High cholesterol

The high amount of cholesterol in the blood can cause blockages in the veins or arteries. This reduces blood flow, slowing blood and facilitating clotting.

When cholesterol accumulates in the walls of the vascular system, blood cells can begin to accumulate in the region, which can also lead to the formation of thrombi.


Obesity is a serious risk factor for thrombosis for several reasons. In addition to the problems related to cholesterol, the presence of excess weight increases the constriction of the veins, both when standing and when sitting, which facilitates the appearance of thrombosis.

There are studies that connect body mass index ( BMI ) above 30, which are considered indicators of obesity, with thrombosis, especially when another risk factor is present.

Read more: How to lose weight healthily: diet, exercise, medicine, menu

Advanced age

In the elderly, the clotting process is accelerated, which facilitates the formation of thrombi. This is because hydration in the elderly is usually less, since the feeling of thirst at this age can be reduced, which generally decreases the amount of water ingested and the level of hydration in the body.

But it is worth mentioning that even with ideal hydration, however, aging remains a risk factor.

Mobility difficulty

Mobility problems, such as physical disability, old age, obesity, physical inactivity and recovery from surgery can facilitate thrombosis because the patient usually ends up staying in the same position for a long time, which constricts certain veins and arteries.


People with diabetes are more likely to develop thrombosis. The disease damages and causes inflammation in the microcirculation area (blood capillaries, which are on the border between arteries and veins), which facilitates the formation of thrombi.

Professionals who can’t move much

People who spend too much time without being able to get up because of work, such as truck or bus drivers, can develop thrombosis more easily, as long periods in the same position reduce blood flow in the legs, facilitating the formation of clots.

Family history

If a relative of yours has had a thrombosis, it is possible that you are at some genetic risk factor. There are several conditions that can facilitate blood clotting and thrombus formation, such as genetic mutations, so it is a good idea to know about your family history.

History of thrombosis

If you have had thrombosis before, it is possible that you are still in one of the risk groups, since the identification of the causes is not always easy or possible. Remember to visit the doctor often to find out about your health.


Injuries that affect the veins or arteries can cause the formation of thrombi, leading to thrombosis. Likewise, it is possible that lesions in the vascular system, or close to it, cause inflammation, which can also lead to thrombosis.


Having major surgery is a risk factor for the development of thrombosis. Both the mobility problem and the trauma suffered by the veins and arteries can increase the chances of thrombus formation.

Symptoms of thrombosis

Symptoms of thrombosis, regardless of type, tend to be similar. However, when it comes to deep vein thrombosis, the signs can be quite subtle and can remain hidden for a long time, until the thrombus becomes large.

When thrombosis affects a very small vein or artery, it is possible that it will never be detected or show symptoms. However, when the disease affects thicker and more important veins and arteries, symptoms may appear. Are they:


Especially in deep vein thrombosis, the pain may appear diffuse, spread throughout the affected limb. There may be tenderness along the veins, which is a sign of thrombosis.

Elevated temperature

The affected region, which is often the leg, can become hot compared to the other leg. This is because the inflammatory process in the veins causes the region to heat up.

It can cause a burning sensation in the limb.

Edema (swelling)

The swelling happens due to the accumulation of liquids in the region.

Color change

The skin is different in color, darker. It may be reddish (erythema) or, in more severe cases, bluish (cyanosis).


The affected region may have tightened muscles because of the thrombosis.

Symptoms related to pulmonary embolism

When a clot blocks a pulmonary artery, a pulmonary embolism is characterized. A blood clot is not always the cause of embolisms, which can be the result of an arterial blockage by any material, but thrombi detached from thrombosis are the most frequent cause.

Pulmonary embolism causes extra symptoms, in addition to those already mentioned, such as shortness of breath and difficulty in breathing, in addition to fainting.

Stroke-related symptoms

As in the case of pulmonary embolism, strokes are not necessarily caused by thrombi, but it is a common cause. When it happens, stroke symptoms appear, such as headaches, neurological problems, nausea and vomiting.

In addition, there is a possible paralysis of some functions, such as the movement of one side of the face or arms, slurred or impossible speech. It is important to seek medical help urgently if a stroke is suspected.

How is the diagnosis of thrombosis made?

When thrombosis is suspected, some tests can be performed to confirm the problem, thus allowing treatment. The doctors responsible for the diagnosis and treatment of thrombosis can be the angiologist , responsible for the care of the circulatory and lymphatic system, or the vascular surgeon .

The tests performed for diagnosis are:


Ultrasonography uses sound waves to create an image of the inside of the body. The technique can be used in the region where a thrombus is suspected to identify it within the vein or artery.

However, sometimes, even ultrasound is not able to find a small thrombosis.

In deciding whether further tests will be done, some factors are considered. For example, if the patient has risk factors for the development of the disease, such as relatives with a history of thrombosis, if he is a smoker, if he is obese, if he has recently undergone surgery, if he remains for a long time.

If the ultrasound does not indicate a thrombosis and the person is not in the risk groups for the disease, it is possible to consider other diagnoses, but when the patient is in these risk groups, another test is recommended.


The D-dimer test is used to identify the presence of thrombi when finding the D-dimer, a material that is produced during fibrinolysis . Fibrinolysis is the process by which clotted blood cells are destroyed.

If there is excess D-dimer in the blood, it means that the clotted cells are being destroyed, in which case it is because they are present somewhere in the body.

The test is not recognized for its accuracy and sensitivity, so it cannot be used alone for the diagnosis of thrombosis. Several other conditions can cause the substance to rise in the blood, such as liver disease, pregnancy, inflammation, cancer , recent surgery, among other things.

That is why it is usually used only in patients who are in some risk group, but whose ultrasound did not reveal the presence of thrombi.

If the result of the D-dimer test is normal, it is possible to follow the condition only after a few months. However, if the D-dimer is elevated, the doctor may schedule another ultrasound scan within a week to try to find the clot again.


Venography is another test capable of finding thrombi in the veins, slightly more accurate than ultrasound. In the past, venography was used to diagnose thrombosis, but it has been replaced by ultrasound due to the faster results and the advantage of not being invasive.

The venography procedure is an x-ray of the veins. A contrast is injected into a vein and an x-ray machine is used so that the vein blocks and deviations are especially clear in the image thanks to the contrast.

Approximately 2% of people may experience allergic reactions to the dye, but sensitivity tests are performed for this.

Complementary exams

There are people who develop recurrent thrombosis. In such cases, they can be tested for blood clotting, which can be high for a variety of reasons, such as genetics.

Other causes are possible and there are tests that the doctor can ask to check, according to the medical survey and the patient’s clinical condition.

Can thrombosis be cured?

Yes , thrombosis is curable. When the disease is detected and the patient follows drug treatment to eliminate thrombi, thrombosis is eliminated.

What is the treatment for thrombosis?

There are some treatment options for thrombosis, ranging from medications to physical methods. Are they:

Drug treatment

The treatment for thrombosis can be medication. Anticoagulants are used, substances that make blood clotting more difficult, together with thrombolytics, which destroy already coagulated blood cells, reducing and eliminating the existing thrombi.

Anticoagulants are used to prevent thrombosis from causing pulmonary embolism or a stroke, and they can be used to prevent thrombus formation in people at risk (such as after major surgery).

Lower Vena Cava Filter (FVCI)

There is also the possibility of installing a Filter in the Lower Vena Cava (FVCI). This filter is a small structure placed via a catheter in the inferior vena cava (the main and widest of the veins that takes blood from the lower limbs to the heart), and serves to prevent clots from passing and reaching narrower veins, which can become clogged.

The procedure is indicated for patients who are at risk of developing thrombosis or pulmonary embolism due to thrombosis, but cannot use anticoagulants due to some contraindication.

However, there are some problems with FVCI treatment. There is no scientific evidence that the filter completely prevents pulmonary embolism, although it can reduce the chances.

In addition, there may be complications due to the presence of the filter, such as displacement of the region where it was placed. It is also possible that a thrombus that would normally pass through the vena cava gets stuck in the filter, blocking the passage of blood.

Therefore, we seek to use FVCI on a temporary basis, in patients who cannot use anticoagulants or in those where the anticoagulant medication is not effective to prevent the formation of thrombi for some reason.

It is recommended to remove the FVCI as soon as possible, seeking to replace it with the anticoagulant medication when and if the contraindication is overcome.


Surgery for the treatment of thrombosis is rare, but feasible. It is used when thrombi do not respond to drug treatment and are at risk of gangrene (tissue death) in a limb of the body. Surgery to remove a thrombus is called a thrombectomy .

Surgery can be done in three different ways. The first involves inserting a catheter with a balloon that is inflated after passing through the thrombus and then pulled, bringing the clot with it. The problem with this procedure is that it can cause damage to the vessel, leading to new thrombi.

It can also be done through a catheter that sucks the thrombus, removing it and causing less injury at the site.

In a third option, thrombectomy can be done with a direct incision in the affected vessel to remove the clot, that is, without the use of a catheter.


In extreme cases, amputation of the limb may be necessary for the treatment of thrombosis. This happens when a large vessel is completely blocked by thrombi, which can trigger tissue necrosis. When too much tissue enters necrosis, amputation is the only solution.

Thrombosis usually reaches this point only when it is ignored, but it is possible that the disease will progress quickly enough to cause necrosis in a short time.

Therefore, it is essential that the symptoms are noticed quickly and take the person to the hospital, since in addition to the necrosis, the other consequences of the clots, such as pulmonary embolism and ischemic stroke, can appear overnight.

Medications for thrombosis

The drugs recommended for thrombosis are usually anticoagulants or thrombolytic drugs , which destroy clots. The most used are:


  • Hemofol ( Sodium Heparin );
  • Enoxalow ( Sodium Enoxaparin );
  • Pradaxa ( Dabigatran Etexilate );
  • Marevan ( Sodium Warfarin );
  • Arixtra ( Sodium Fondaparinux ).

Thrombolytic drugs

  • Zestril ( Lisinopril );
  • Streptase ( Streptokinase );
  • Actilyse ( Alteplase ).


NEVER self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained in this website is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.

Living with thrombosis

Some people may experience chronic thrombosis if they are predisposed to the formation of clots within their circulatory system, due to genetic diseases that affect clotting, reduced movements for some reason, among other reasons.

The important thing in these cases is to prevent the disease, reducing the chances that a new thrombus will form in the veins or arteries. Taking care of habits, quitting smoking, eating healthy, exercising, keeping your body moving are important for you to reduce all chances of your thrombosis coming back.

Anticoagulant medications may be needed for some time if the thrombosis is related to your blood clotting.

In addition, there are compression stockings, which apply light pressure to the legs, making the blood flow more easily. This type of sock is used in hospitals after surgery to prevent the patient from developing a thrombosis by spending too much time in bed recovering.

Warfarin and Vitamin K

Warfarin is one of the most widely used anticoagulants in the treatment of thrombosis due to its effectiveness.

Like any drug, its effect can be changed according to interactions with other active ingredients, but in the case of warfarin, nutrition is also capable of causing these changes, specifically vitamin K .

Vitamin K reduces the effect of warfarin, so it is important that you do not change your diet during treatment. If you reduce the average amount of vitamin K, the effect of the drug can become too strong, just as if you increase the vitamin intake, the effect can be reduced, increasing the chances of the appearance of clots. So, keep your food consumption with this vitamin stable.

Foods with vitamin K include:

  • Broccoli;
  • Chard;
  • American lettuce;
  • Spinach;
  • Parsley;
  • Green cabbage;
  • Arugula;
  • Asparagus;
  • Olive oil.

Avoid dietary changes during treatment with warfarin and follow your doctor’s recommendations.

In addition, this is a drug with several drug interactions . This means that its use with other medicines can cause changes in the expected effects of both. Tell your doctor what medications you are taking before starting treatment.


Thrombosis is curable and treatment is usually able to reverse it, but it is important to remember that if you have had thrombosis once, you are likely to have more. Medical follow-up should be regular and habits should change to ensure that the chances of return of the thrombi are as small as possible.

It is possible to have a high quality of life after thrombosis and even with a predisposition to the disease. Prevention becomes very important after a diagnosis, precisely to ensure the maintenance or recovery of quality of life.

Complications of thrombosis

Thrombosis is a condition that can cause several serious complications, so it is very important that it is treated as soon as possible. Among the most frequent are:

Pulmonary embolism

When a clot breaks off and goes to a pulmonary artery, or when it develops in it, a blockage can form and so happens the so-called pulmonary embolism.

By definition, pulmonary embolism can occur when any material causes a blockage, but the most common is that the material is a blood clot – a thrombus.

The clot originating elsewhere in the body is more common than those that form directly in the region of the lungs. Pulmonary embolism can cause shortness of breath, cough , chest pain and death.

Ischemic stroke

An Ischemic Stroke (ischemic stroke) happens when something blocks the path of arteries in the brain. As with pulmonary embolism, what usually causes this type of stroke is a clot that has come off.

This type of condition is also an emergency, as the lack of circulation in an area of ​​the brain can lead to the death of neurons, which leaves severe sequelae that vary depending on where the thrombus is in the artery. Among the complications are paralysis, severe headache , loss of speech and brain functions, which can cause death.

Heart attack

heart attack is the death of an organ or a region of it. When a clot prevents the passage of blood to certain regions, the blood is not able to oxygenate the cells, which results in their death.

The condition can happen anywhere on the body, but the best known is myocardial infarction, the famous heart attack. If a thrombus blocks the path of arteries that supply the heart with oxygen, a part of the organ can die. The heart is an essential organ and heart attacks can be lethal, depending on the size of the affected region.

But it is clear that infarctions can affect all organs. Liver, kidneys, spleen, stomach, intestines, anyone. It is enough that something prevents its oxygenation, which is perfectly within the possibilities of a thrombus that detaches from a vein anywhere in the body.


Necrosis is the death of tissue, which begins to rot. Infarcts are necroses located in organs when a clot blocks the blood’s path, but it can happen to entire limbs. If a deep vein thrombosis succeeds in blocking the blood flow of a large vein, the blood ends up being trapped in the organ, which dies.

This condition can affect a hand, a foot, even an entire leg. It is not possible to recover necrotic tissue and it needs to be removed, as dead cells attract bacteria that can cause serious infections that can affect the entire body.

Generalized infection

Widespread infection can occur when bacteria reach the bloodstream and spread throughout the body through the vascular system. After a necrosis, bacteria can begin to accumulate in dead tissue, eventually spreading to living tissue, and the result is an infection that can spread throughout the body.


All the complications listed here can lead to death. Thrombosis is a serious, dangerous disease that must be treated urgently and seriously to prevent people from dying from it.

How to prevent thrombosis?

Prevention of thrombosis is essential, especially for those who are already predisposed to the disease. Among the measures that can be adopted are:

Compression socks

Compression stockings are stockings made to lightly tighten the legs evenly, facilitating the transport of blood through the veins.

They are used after major surgery, where the patient will be forced to recover lying down for several days, to prevent thrombosis, along with anticoagulant medications.

Socks are also a good idea for flights and long journeys. If you are in any of the risk groups, consider buying a pair for those times when you should be sitting for a long time. But do not use them every day, as with use, the fabric starts to become looser and the effect is reduced.

Do not smoke

Tobacco slows down circulation, which facilitates the formation of thrombi, in addition to causing inflammation in the veins, phlebitis, which can also cause thrombosis. Quitting smoking considerably reduces your chances of developing the disease.

Eat well

A balanced diet can keep your body healthy and protected from various diseases. In this case, avoiding too many cholesterol-rich foods, for example, reduces the chances of clots forming in your vascular system.

Take care of your weight

Staying at a healthy weight is very important for health. If you are overweight for your body, the chances of thrombi will rise considerably.

Do exercises

Exercises are good for your heart, muscles, circulation and weight. Vascular function becomes more efficient and healthy, which is essential for clots to stay away from the veins.

Read more: Exercises to lose belly: how to do, aerobic and abdominal

Don’t stay in the same position too long

If you work seated, try to get up and take a short walk from time to time. Try not to lie in the same position for long periods. The habit of moving and allowing blood to pass properly through your body prevents thrombosis from forming in your veins and arteries.

Common questions

Does air travel cause thrombosis?

Yes and no. It is not the plane that increases the chances of you developing a thrombosis, but the time you spend on it. Long airplane travel means a lot of sitting time . All this time in the same position can reduce blood flow in the legs, which in turn facilitates blood clotting in the veins.

So it’s not the plane that causes the thrombosis. Any long period of sitting can lead to thrombi in the legs. Train, car and bus travel also present this risk.

What foods to eat to prevent thrombosis?

There are no specific foods to prevent thrombosis, but there are some that you can avoid in excess to reduce the chances. Salt and fats are necessary foods for the body, but in excess they can facilitate the formation of clots.

Can varicose veins turn into thrombosis?

Yes, in some cases. Varicose veins make it easier for the blood to stand still or to move little in a certain region, which provides an ideal environment for coagulation within the blood system. Therefore, it is important to observe varicose veins well and consult a doctor.

Thrombosis is a disease caused by the formation of clots within the circulatory system and can be extremely dangerous if left untreated. Share this text with your friends so they can take care of their own bodies too!