A clot that forms in a vein can break off and travel with the blood to the lungs, causing pulmonary embolism. Sudden shortness of breath, chest pain, coughing up blood, faintness or loss of consciousness require immediately calling for help at 112 or 999.

A long journey means many hours with almost no movement

While driving a car, the legs remain in a similar position for a long time. The movements involved in operating the pedals are small and do not replace walking, during which the calf muscles help pump blood toward the heart. Sitting for many hours limits the work of this natural pump and promotes blood stasis in the legs.

The risk of travel-related thrombosis is usually analyzed for journeys lasting at least four hours. This is not, however, a rigid threshold after which a clot automatically forms. The time spent without movement and individual risk factors are important. In a healthy person, the risk remains low, but it increases when one or more additional factors are present:

  • previous deep vein thrombosis, pulmonary embolism, diagnosed thrombophilia or thrombosis in the immediate family,
  • recent surgery, injury, hospitalization or prolonged immobilization,
  • active cancer,
  • pregnancy, the postpartum period or taking estrogens, for example as part of contraception or hormone replacement therapy,
  • obesity and age over 40, although the risk continues to increase with age.

Symptoms do not have to appear immediately after the drive ends. They may develop over the following days or weeks, so during a consultation you should tell the doctor about a recent long journey.

Muscle strain and thrombosis can cause similar symptoms

Strain-related pain often appears after exercise, a long walk, a cramp or sitting in an uncomfortable position. It may worsen with a particular movement and gradually subside. The nature of the pain alone does not, however, make it safe to rule out thrombosis.

Deep vein thrombosis most often affects one limb. It may be accompanied by:

  • calf or thigh pain or tenderness,
  • swelling of part or all of the leg,
  • noticeably warm skin,
  • redness or bluish discoloration,
  • a feeling of pressure or heaviness in the leg.

Symptoms may be mild and swelling may be slight. This is not enough to rule out a clot in a vein on your own. Thrombosis cannot be confirmed or ruled out by squeezing the calf, moving the foot or comparing the appearance of both legs. Such home “tests” do not replace a medical examination.

One-sided pain combined with swelling, warmth or a change in skin color requires urgent medical assessment on the same day. People with additional risk factors need to be particularly alert. Do not wait several days to see how the situation develops or assume that the cause is only the long drive.

Shortness of breath and chest pain are warning signs

A fragment of a clot can break away from the vein wall and travel with the blood to the lungs. This causes pulmonary embolism, which can directly threaten life. It can also develop when no clear leg symptoms appeared earlier.

Immediate help is required for:

  • sudden or rapidly worsening shortness of breath,
  • chest pain, especially pain that worsens when breathing in,
  • coughing up blood,
  • a very rapid heartbeat,
  • severe weakness, faintness or loss of consciousness.

With such symptoms, call 112 or 999. Do not drive yourself to the hospital or wait for a teleconsultation.

How does a doctor check whether it is thrombosis?

A description of the pain alone is not enough for a diagnosis. The doctor takes a medical history, examines the patient and assesses risk factors. They may also use the Wells score, which helps estimate the clinical probability of thrombosis. It is not, however, a test intended to be performed independently at home.

The order of further tests depends on the result of the clinical assessment. In some patients, D-dimer levels are measured. A result below a specific threshold may help rule out thrombosis if its clinical probability is low. An elevated D-dimer level does not, however, confirm the disease. It may occur, among other situations, after surgery, during an infection, in pregnancy or in the course of cancer.

The primary imaging test performed when thrombosis is suspected is an ultrasound scan of the veins of the lower limb. The doctor decides whether D-dimer testing or an urgent ultrasound examination is needed first. Do not order D-dimer testing on your own or interpret the result without considering the symptoms and the clinical probability of thrombosis.

When can an online consultation help?

A person with a history of thrombosis, recent surgery or several risk factors can discuss a planned journey with a doctor online before departure, for example at DoktorPlus.pl. The patient should provide their medical history, a list of medications taken and the expected length of the journey. The doctor will assess whether regular stops and leg exercises are sufficient or individual recommendations are needed.

If symptoms have already appeared after the journey, an online conversation may help initially determine what to do next, but it cannot confirm or rule out thrombosis. One-sided swelling combined with pain or warmth in the leg requires an in-person examination. A teleconsultation should not delay an ultrasound if the doctor considers it necessary.

Do not take aspirin or anticoagulants “just in case” on your own. They may cause bleeding, and any pharmacological prophylaxis is selected individually. For people at increased risk, a doctor may recommend appropriately fitted compression stockings. They are not necessary, however, for everyone taking a longer journey.

How can the risk be reduced during a long drive?

During a journey lasting many hours, plan stops whenever possible every one to two hours. The driver should get out of the car, walk around and activate the calf muscles. A few foot movements while operating the pedals do not replace such a break.

Passengers can flex and extend their feet, tense their calf muscles and change position during the journey. Clothing should not tightly constrict the waist or legs. Recommendations on movement and breaks during long journeys are also provided by the Narodowy Fundusz Zdrowia.

Drinking water helps avoid dehydration, but there is no evidence that hydration alone prevents travel-related thrombosis. It does not replace movement or prophylaxis recommended for a person at increased risk.

If one leg becomes swollen, warmer and painful after a journey, taking another walk is not a way to check whether it is only strain. Do not try to “walk off” such symptoms—they require urgent medical assessment.

This material is for informational and educational purposes and does not replace an examination or medical consultation. In the event of sudden shortness of breath, chest pain, coughing up blood, faintness or loss of consciousness, call 112 or 999.

Sources:

  • CDC – risk of blood clots during long-distance travel
  • NICE – diagnosis and treatment of venous thromboembolic disease
  • NHS – deep vein thrombosis
  • NHS – pulmonary embolism
  • NFZ – how to prevent thrombosis