Table of Contents

I. Blood Loss Prevention

II. Deep Vein Thrombosis

III. Pulmonary Embolism

IV. Post-Phlebitic Syndrome

V. Complications with Blood Thinners

VI. Prevention

VII. FAQ: How Can I Recognize Blood Clot Complications and Know When to Get Help?

Blood Loss Prevention

Blood clotting is a natural process that helps prevent excessive blood loss after an injury. A clot forms when platelets, proteins, and other blood cells stick together over the injured area, stopping the bleeding while the wound heals. Once healing is complete, the body usually breaks down and removes the clot. [1]

Blood clots can become dangerous when they form unnecessarily, develop in excessive numbers, have an abnormal structure, or fail to dissolve properly. Depending on where a clot forms, it may cause a heart attack, stroke, pulmonary embolism, kidney damage, or injury to other organs. [2]

Some people at high risk of blood clots may be prescribed blood thinners. These medications help prevent new clots from forming and keep existing clots from getting larger, but they do not dissolve clots that have already formed. [1] Treatment options may include Coumadin (warfarin), or a direct oral anticoagulant such as Eliquis (apixaban) or Xarelto (rivaroxaban). [3] [4] Read on to learn about other possible complications of blood clots. 

Deep Vein Thrombosis

Deep vein thrombosis (DVT) occurs when a blood clot forms in a vein deep inside the body. It most often affects the lower leg, thigh, or pelvis, but it can also develop in the arm or abdomen. [2] [5]

DVT may develop when blood flow slows, a blood vessel is injured, or a condition makes the blood more likely to clot. Risk can increase during a long flight or car ride, an extended hospital stay, or recovery from surgery because these situations may limit movement. [5]

Some people with DVT have no noticeable symptoms. [5] When symptoms occur, they may include:

• Pain near the clot
• Swelling
• Red or discolored skin
• More noticeable veins beneath the skin [5]

See a doctor immediately if you think you may have DVT. Part of the clot can break off and travel to the lungs, causing a serious condition called a pulmonary embolism. [5]

Pulmonary Embolism

A pulmonary embolism (PE) occurs when a blood clot forms elsewhere in the body, often in a deep vein in the leg, breaks loose, and travels to an artery in the lung. The clot can suddenly block blood flow through the lung. Deep vein thrombosis is the most common cause of a pulmonary embolism. [6]

Symptoms of a pulmonary embolism may include:

• Sudden shortness of breath
• Chest pain that is usually worse when breathing
• Coughing or coughing up blood
• Dizziness, lightheadedness, or fainting
• A fast or irregular heartbeat
• Sweating
• Low blood pressure [6]

A pulmonary embolism can reduce blood flow to the lungs, damage lung tissue, lower blood oxygen levels, and affect other organs. Some people with a PE may also have symptoms of DVT, such as pain or swelling in the affected leg, tenderness, warmth, redness, or discolored skin. [6]

Post-Phlebitic Syndrome

Post-phlebitic syndrome, also called post-thrombotic syndrome, is a complication that can develop after a DVT in the leg. A DVT can damage the valves inside the affected veins, causing them to weaken or leak. This allows blood to collect in the leg instead of flowing efficiently back toward the heart. [7]

Symptoms occur in the same leg as the DVT and may include:

• Swelling
• A feeling of heaviness in the leg
• Leg pain that may worsen while standing and improve with rest or leg elevation
• Darkening or redness of the skin
• Widened veins [7]

Post-thrombotic syndrome may develop within the first six months after a DVT, although symptoms do not always appear right away. Compression therapy is the main treatment and may include prescription compression stockings or an intermittent pneumatic compression device. Depending on the symptoms, treatment may also involve skin care products, wound care, or surgery to remove a blockage or repair damaged vein valves. [7]

Complications with Blood Thinners 

Blood thinners can help prevent new blood clots from forming and stop existing clots from getting bigger, but they can also cause side effects. Bleeding is the most common side effect. Other possible side effects include upset stomach, nausea, and diarrhea. [8]

Contact your healthcare provider if you experience signs of serious bleeding, such as:

• Menstrual bleeding that is much heavier than normal
• Red or brown urine
• Red or black bowel movements
• Bleeding from the gums or nose 
• Brown or bright red vomit
• Unusual bruising
• A cut that does not stop bleeding
• Severe pain (headache or stomachache)
• Dizziness or weakness [8]

Prevention

You can lower your risk of blood clots by staying active and avoiding long periods without movement. Exercise helps keep blood flowing, and during long trips or extended periods of sitting, try to get up and move around every two to three hours. Staying hydrated, avoiding smoking, and maintaining a healthy weight may also help reduce your risk of developing blood clots. [1]

In some cases, your doctor may prescribe blood thinners. These medications can help prevent new clots from forming and keep existing clots from getting bigger. If you are prescribed a blood thinner, follow your doctor’s instructions closely. [1]

FAQ: How Can I Recognize Blood Clot Complications and Know When to Get Help?

Seek medical care promptly if you think you may have a blood clot or a complication from one. Deep vein thrombosis can cause leg pain, swelling, redness, discoloration, or visible veins, and part of the clot can break off and travel to the lungs. A pulmonary embolism is urgent and may cause sudden shortness of breath, chest pain that worsens when breathing, coughing up blood, dizziness, fainting, a fast or irregular heartbeat, sweating, or low blood pressure.

You should also watch for longer-term or treatment-related complications. After a DVT, post-thrombotic syndrome can cause swelling, heaviness, pain that worsens with standing, skin darkening, redness, or widened veins. If you take a blood thinner, contact your healthcare provider if you notice serious bleeding signs such as red or brown urine, red or black bowel movements, bleeding from the gums or nose, unusual bruising, vomiting blood, dizziness, weakness, or a cut that will not stop bleeding.

To respond to possible blood clot complications:

1. Get urgent help for sudden shortness of breath, chest pain, coughing up blood, fainting, or symptoms of a possible stroke.
2. Call your doctor right away for leg swelling, pain, redness, warmth, or visible vein changes.
3. Tell your provider about recent surgery, long travel, limited movement, or a previous clot.
4. Take blood thinners exactly as prescribed if your doctor has given them to you.
5. Report serious bleeding symptoms while taking a blood thinner.
6. Ask your doctor whether compression therapy, follow-up care, or lifestyle steps may help prevent future complications.

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.