Thrombosis | Doctors and information

Thrombosis refers to the formation of a blood clot (thrombus) in a blood vessel that obstructs or completely interrupts the normal flow of blood. Thrombosis is particularly common in the deep veins of the legs - a condition that can have serious consequences such as a pulmonary embolism if left untreated. However, thrombosis can be easily treated if detected early.

In this article, you will find out how thrombosis develops, what the typical symptoms are, how the diagnosis is made and what treatment options are available. You can also find selected specialists for thrombosis here.

Definition: What is thrombosis?

In a thrombosis, a blood clot (medical term: thrombus) blocks a blood vessel. This interrupts the normal blood flow. Veins are usually affected, especially the deep leg and pelvic veins - this is known as deep vein thrombosis (DVT). Arterial thromboses, i.e. blockages in arteries, can also occur, but are rarer.

An adult has around 5 liters of blood in their body - around 8 percent of their body weight. This blood circulates continuously through arteries and veins. If a thrombus forms, blood circulation is disrupted. This can lead to serious consequences such as a pulmonary embolism - an emergency in which the clot enters the pulmonary artery.

The disease is relatively common in industrialized countries: Around two in 1,000 people suffer a thrombosis every year.

Thrombosis in the deep veins of the leg

The most common form is deep vein thrombosis. Here, a blood clot blocks the venous valves. The blood backs up, the affected leg swells and hurts. Without treatment, there is a risk that the clot will break free and travel to the lungs.

Thrombosis in the deep veins of the legs: A blood clot (thrombus) blocks the venous valves and leads to blood congestion @ Анна Богатырева /AdobeStock

Symptoms: How do I recognize a thrombosis?

A thrombosis does not always manifest itself immediately through noticeable symptoms. Nevertheless, there are typical warning signs - especially in the case of venous thrombosis:

• One-sided leg swelling, often in the lower leg or foot
• Feeling of tension or pressure pain in the calf
• Pain when stepping or walking
• Bluish or reddish discoloration of the skin
• Warming or shining of the affected skin area

These symptoms are warning signs. If you suspect a thrombosis, you should seek medical help immediately. An untreated thrombosis can be life-threatening.

Causes & risk factors: How does thrombosis develop?

Thromboses occur when several factors come together. The so-called Virchow triad describes three main causes:

1. Slowed blood flow - e.g. due to prolonged bed rest or prolonged sitting (e.g. on an airplane)
2. Changes to the vessel wall - e.g. due to inflammation, injury or arteriosclerosis (vascular calcification)
3. Increased tendency of the blood to clot - e.g. due to a lack of fluids, medication or genetic predisposition

Overview of common risk factors:

• Prolonged bed rest (after operations, hospital stays)
• Lack of exercise (e.g. sitting for long periods when traveling)
• Lack of fluids
• Pregnancy and puerperium
• Birth control pills (hormonal contraception)
• Smoking
• Being overweight
• Varicose veins
• Arteriosclerosis
• Cancer
• Hereditary coagulation disorders
• Previous thrombosis

Thrombosis is often visible from the outside @ hriana /AdobeStock

Examination & diagnosis: How is thrombosis diagnosed?

First, the doctor assesses the symptoms and carries out a physical examination. If there are grounds for suspicion, further diagnostics are carried out:

• D-dimer test: A simple blood test that shows whether blood clots are forming or breaking down in the body.
• Ultrasound (compression sonography): The most important examination for suspected venous thrombosis.
• Phlebography: X-ray examination of the leg veins with contrast medium - rarely used, e.g. in the case of unclear findings.
• Wells score: An evaluation system that assesses the probability of thrombosis based on clinical criteria.

Treatment: How is thrombosis treated?

Rapid treatment is crucial to prevent the progression of the thrombosis and a pulmonary embolism. The most important treatment steps are

Blood-thinning medication (anticoagulants):

• Start often with heparin injections
• Further treatment usually with tablets such as rivaroxaban, apixaban, dabigatran or warfarin

Compression therapy:

• Initially wrap bandages
• Then medical compression stockings to relieve the veins and reduce swelling

You must wear the compression stocking where the thrombosis causes congestion @ tibanna79 /AdobeStock

Early mobilization:

• Patients should move to promote blood flow

Surgical interventions:

• In the case of large thrombi, e.g. in the pelvic vein, a thrombectomy (surgical removal of the clot) may be necessary

Bypass operation:

• Only for arterial thromboses - not for venous thromboses

Progression and prognosis: What happens after the diagnosis?

If the thrombosis is treated in time, the prognosis is good. Treatment usually lasts three to six months - in high-risk cases even longer or for life.

Possible long-term consequences:

• Post-thrombotic syndrome (PTS): Chronic symptoms such as leg pain, swelling, skin changes
• Repeated thromboses: Especially with a hereditary tendency or inadequate aftercare

Important: Regular medical check-ups, taking medication consistently and wearing compression stockings can reduce long-term consequences.

Frequently asked questions about thrombosis

How dangerous is a thrombosis? An untreated thrombosis can lead to a pulmonary embolism - a medical emergency. This is why rapid diagnosis and treatment is vital.

Can thrombosis be prevented? Yes. Plenty of exercise, drinking enough fluids, avoiding prolonged sitting and not smoking can help. In the case of risk factors, doctors often recommend preventative medication or compression stockings - e.g. for long-haul flights or after operations.

What is a pulmonary embolism? If part of the thrombus becomes detached, it can travel into the lungs. Symptoms include sudden shortness of breath, chest pain, coughing and restlessness. A pulmonary embolism can be fatal and must be treated immediately.

Conclusion

Thrombosis is a serious vascular disease that can be life-threatening - especially due to possible secondary diseases such as pulmonary embolism. If you know the risk factors and recognize symptoms early, you can protect yourself effectively. With modern diagnostics and timely treatment, the chances of recovery are generally very good.

Glossary: technical terms simply explained

• Thrombus: Blood clot that can block a vessel
• Venous thrombosis: Blockage of a vein by a blood clot
• Arterial thrombosis: Blockage of an artery by a blood clot
• Compression stockings: Special medical stockings that improve venous return
• Anticoagulants: Medication to thin the blood
• Pulmonary embolism: blockage of a pulmonary artery by a blood clot
• Virchow triad: three main causes that together can lead to thrombosis
• Wells score: Evaluation system for assessing the risk of thrombosis