Table of Contents

I. What are Blood Clots?

II. Types of Harmful Blood Clots

III. Symptoms of Blood Clots

IV. Medications for Blood Clots

V. FAQ: What Should I Do If I Think I Have a Blood Clot?

What are Blood Clots?

A blood clot is a mass that forms when platelets, proteins, and other cells in the blood stick together. Whole blood contains red blood cells, white blood cells, and platelets suspended in a liquid called plasma. [1] The amount of blood in the body depends on a person’s size. A newborn has around one cup of blood, while an adult weighing 150 to 180 pounds has approximately 1.2 to 1.5 gallons. [2]

Blood clotting is a natural process that helps stop bleeding after an injury. The process generally involves:

• Platelets and clotting proteins work together to form a blood clot. 
• The clot helps stop bleeding after an injury.
• The clotting process starts and stops as the body needs it.
• After healing takes place, the body usually breaks down and removes the clot. [2] [3]

Blood clot complications can occur when clots form where they should not, the body produces abnormal clots, or clots do not break down properly. These clots may block blood flow and damage organs such as the heart, brain, lungs, and kidneys. [4]

Slow or sluggish blood flow can also increase the likelihood of clot formation, particularly after surgery, during an extended illness, or while sitting for a long period. [4] Read on to learn more about blood clots and treatments such as blood thinners, which can help prevent new clots from forming and keep existing clots from growing.

Types of Harmful Blood Clots 

Thrombosis occurs when a blood clot forms inside a blood vessel and blocks blood flow. [5] There are two main types of thrombosis:

• Arterial: Arterial thrombosis occurs when a blood clot blocks an artery, which carries oxygen-rich blood away from the heart to the rest of the body. A clot in an artery supplying the heart can cause a heart attack, while one in a blood vessel in the brain can cause a stroke. [5]

• Venous: Venous thrombosis occurs when a blood clot blocks a vein, which carries blood from the body back to the heart. Risk factors for these clots may be associated with certain medications, obesity, or a lack of movement. Sitting or lying down for an extended period, such as during a hospital stay or a long trip, can slow blood flow and increase the risk of clot formation. [5] A deep vein thrombosis commonly forms in a vein deep in the body and may cause pain and swelling. It can also break loose and travel to the lungs, causing a pulmonary embolism. [4]

Symptoms of Blood Clots

Symptoms of blood clots vary depending on where the clot occurs in the body. Learn more about area-specific symptoms below.

Arms and Legs

A blood clot that develops deep in an arm or leg vein is known as deep vein thrombosis (DVT). Without treatment, the clot may grow and cause increasing pain or swelling in the affected limb. Part of the clot may also break away and travel to the lungs, where it can block blood flow and cause a pulmonary embolism (PE). A larger clot may lead to more serious complications. [6]

Possible symptoms of a blood clot in the arm or leg include:

• Pain that begins suddenly or develops gradually
• Swelling in the affected area
• Tenderness or pain when touched
• Warm or red skin [4]

Heart and Lungs

A blood clot affecting the heart may cause:

• Chest pain
• Sweating 
• Shortness of breath 
• Pain in the left arm [1]

A blood clot in the lungs is known as a pulmonary embolism. [4] Symptoms may include:

• Shortness of breath 
• Sweating 
• Fever 
• Coughing up blood
• Chest pain [4]

Brain 

Blood clots can form in or travel to blood vessels in the brain. [1] When arterial thrombosis occurs in a blood vessel in the brain, it can lead to a stroke. [5]

Symptoms may include:

• Trouble speaking
• Vision problems
• Seizures
• Weakness on one side of the body
• A sudden, severe headache [1]

Abdomen 

Blood clots can form in the blood vessels inside the abdomen. Symptoms of an abdominal blood clot may include:

• Severe abdominal pain
• Nausea
• Vomiting [1]

Medications for Blood Clots

Blood thinners may be used to treat blood clots because they help prevent new clots from forming and keep existing clots from getting larger. However, they do not dissolve clots that have already formed. The types of blood thinners include:

• Unfractionated heparin (UFH): Heparin is a strong, fast-acting blood thinner that may be given through an IV in the hospital or injected under the skin. IV heparin begins working within minutes, but patients need frequent blood tests so the dose can be adjusted appropriately. [3]

• Low molecular weight heparin (LMWH): LMWH is similar to heparin but can usually be injected under the skin at home. Patients generally do not need regular blood tests while taking LMWH. [3]

• Warfarin: Warfarin is an oral blood thinner that slows the liver’s use of vitamin K to produce clotting proteins. Regular blood tests are needed to measure how long the blood takes to clot and to confirm that the medication is working safely. [3]

• Direct oral anticoagulants (DOACs): DOACs reduce the blood’s ability to form clots. They have a quick onset, are short-acting, have relatively low bleeding risks, and are considered at least as effective as warfarin. Unlike warfarin, DOACs do not require regular blood monitoring and have fewer interactions with medications, supplements, and food. Because they are short acting, missing a dose can quickly reduce protection against blood clot formation. Examples include Eliquis (apixaban) and Xarelto (rivaroxaban). [7]

FAQ: What Should I Do If I Think I Have a Blood Clot?

Seek medical care right away if you think you may have a blood clot, especially if symptoms are sudden, severe, or getting worse. Blood clot symptoms can vary depending on where the clot forms. A clot in the arm or leg may cause swelling, pain, tenderness, warmth, or redness, while a clot in the lungs may cause shortness of breath, chest pain, sweating, fever, or coughing up blood. A clot affecting the brain may cause trouble speaking, vision problems, weakness on one side of the body, seizures, or a sudden severe headache.

If a clot is confirmed, your doctor may recommend treatment based on the type, location, and severity of the clot. Blood thinners may be used because they help prevent new clots from forming and keep existing clots from getting larger, but they do not dissolve clots that have already formed. Treatment options may include heparin, low molecular weight heparin, warfarin, or direct oral anticoagulants such as Eliquis or Xarelto.

If you are concerned about a possible blood clot:

1. Seek urgent medical care or contact your doctor immediately 
2. Tell your provider about recent surgery, long travel, extended bed rest, pregnancy, medications, or a history of blood clots.
3. Ask whether testing is needed to confirm the clot and where it is located.
4. Do not start, stop, or change blood thinner treatment unless your doctor tells you to.
5. Ask your doctor which warning signs should prompt emergency care while taking a blood thinner.

The content in this article is intended for informational purposes only. This website does not provide medical advice. In all circumstances, you should always seek the advice of your physician and/or other qualified health professionals(s) for drug, medical condition, or treatment advice. The content provided on this website is not a substitute for professional medical advice, diagnosis, or treatment.