A blood clot can form when the blood comes into contact with substances in the skin or on vessel walls. Several specific health conditions can cause blood clots.

Blood clots can be stationary. The development of these is known as thrombosis. However, clots can also break loose. These are called embolisms.

Medical complications can arise if blood clots do not dissolve.

In this article, learn about the causes, treatments, and prevention advice associated with blood clots. The article also outlines some possible related conditions and describes when urgent treatment is necessary.

close up of a woman's legs on a plane where the prolonged sitting is one the top causes of blood clotsShare on Pinterest
Periods of prolonged sitting, such as during long-haul flights, can cause blood clots.

The seriousness of the blood clot depends on what type it is. There are two: arterial clots and venous clots.

Also known as an arterial thrombus, an arterial clot is one that develops in an artery. These can stop the flow of blood to major organs and lead to tissue damage. Treatment is often essential and will depend on where the clot is.

A venous clot, or a venous thrombus, forms within a vein. These develop slowly and can restrict blood flow. If a venous clot breaks loose, it can move to other parts of the body.

According to the Texas Heart Institute, almost 6 million people in the United States have a blood clot in their veins.

Although blood clots can be harmless, they are sometimes associated with serious medical conditions.

The sections below will outline some of these in more detail.

Deep vein thrombosis

Deep vein thrombosis (DVT) occurs when a venous clot develops deep within the leg, pelvic area, lungs, or brain.

DVT is the third most common cause of death from cardiovascular disease. It also accounts for most cases of pulmonary embolism.

DVT does resolve itself in many cases, but it can be life threatening if it travels to the lungs and blocks blood flow (pulmonary embolism).

Although it can occur if someone has an underlying health condition, DVT can also develop if a person remains stationary for a long time.

Some symptoms of DVT include:

  • gradual leg pain, which can feel like cramp or soreness
  • red or discolored skin on the leg
  • warmth or tenderness in the leg
  • foot or calf pain
  • swelling in the arm

The Centers for Disease Control and Prevention (CDC) report that DVT and pulmonary embolism could affect as many as 900,000 people each year. Early diagnosis and treatment are essential.

Heart conditions

Excessive blood clotting in the heart can lead to pulmonary embolisms. This blockage of the pulmonary artery, which supplies blood to the lungs, is dangerous and can be life threatening.

Some symptoms include:

  • sharp, stabbing chest pain and difficulty drawing a breath
  • pain in the left arm
  • an irregular or faster heartbeat, rapid breathing, and sweating
  • a cough that produces blood or mucus
  • dizziness

The symptoms are similar to those of a heart attack, which occurs when blood flow to the heart suddenly becomes restricted.

Blood clots can also restrict oxygen to the heart. If the blood flow to the heart muscle does not return within 20–40 minutes, there is a risk of death.


A blood clot in the brain is also known as a stroke and can cause many symptoms. These include:

  • severe headaches
  • facial weakness
  • speech and vision difficulties
  • pain and numbness in the arms and legs

Symptoms occur on the opposite side of the body from the location of the blood clot.

A blood clot in the brain cuts off the blood supply, leading to an embolism. People should seek medical assistance immediately if they suspect a blood clot in the brain.

Abdominal blood clot

A blood clot in the abdomen occurs in the veins that drain blood from the intestines. It is a type of DVT that can lead to symptoms including severe stomach pain, nausea, diarrhea, and vomiting.

There are many causes of an abdominal blood clot. These include:

Kidney blood clot

A blood clot in the kidney is dangerous, as it can prevent the removal of waste from a person’s body. Key symptoms include:

  • blood in the urine
  • pain in the abdomen, legs, or thighs
  • fever
  • nausea

The symptoms of blood clots are similar to those of many other conditions. For this reason, diagnosis can sometimes be challenging. A doctor will usually need to take a person’s medical history to be sure.

People at moderate risk of experiencing a blood clot include those who:

  • have recently engaged in a lengthy period of travel or bed rest
  • have obesity
  • are pregnant
  • have a family history of blood clots

However, most cases of DVT are related to specific, identifiable trigger events. These include hospitalization, major surgery, trauma, and periods of immobility.

Treatment options depend on the location and severity of the blood clot.

In general, options include a venous ultrasound or a CT angiography scan. In extreme cases, a surgical procedure known as catheter-directed thrombolysis may be necessary.

A doctor may also prescribe medication such as anticoagulants, or blood thinners.

Research into blood clot diagnosis and treatment is ongoing.

If a person suspects a blood clot or has symptoms in their leg, they should immediately see a doctor. The doctor’s aim will be to prevent the clot from expanding or breaking loose.

It is impossible to eradicate the potential for blood clots completely, but there are some ways to lower the risk.

For example, people can:

  • Exercise often: Physical inactivity can lead to the formation of blood clots.
  • Travel safely: Stretch the legs regularly on long-haul flights. If there is a layover, taking a walk can get the blood moving again.
  • Stay hydrated: Drinking water regularly is good for general health, but it is especially important when traveling. Avoid caffeine and alcohol, if possible.
  • Quit smoking: Cigarettes can negatively affect blood circulation.
  • Maintain a moderate weight: Obesity increases the risk of blood clots, as excess weight increases pressure in the veins.
  • Be aware of birth control pills: These can increase the risk of blood clots. A doctor can offer advice on alternative contraception.

Although blood clots can have serious consequences, various medications and straightforward surgical procedures can usually treat them.

With DVT, redness or swelling will often appear on the leg and require treatment. Symptoms such as chest pain, shortness of breath, loss of speech, and dizziness will require assessment by a healthcare professional.

Blood clots are quite common, but adopting a healthful lifestyle can help prevent them. Anyone with concerns about blood clots can speak to a doctor about lowering their risk.