A swollen leg, which changes color, with dilated veins, should be extra vigilant about the risk of pulmonary embolism.

Both phlebitis and pulmonary embolism are venous thrombotic diseases. "They are characterized by the formation of a blood clot in the deep venous system, generally in the thigh or the calf, which will block the return of blood to the heart," describes Professor Ygal Benhamou, head of the unit of internal vascular medicine and thrombosis at Rouen University Hospital. The clot can remain in place, this is called deep vein thrombosis or phlebitis. It can also go up to the lungs and obstruct the pulmonary artery… It is pulmonary embolism. ”

Causing 7 to 8 out of 10 embolisms

Each year, between 50,000 and 100,000 cases of deep vein thrombosis are treated in France, while hospitalizations for pulmonary embolism concern more than 35,000 people. "In 70 to 80% of cases, embolism is a complication of phlebitis of the lower limbs", specifies Pascal Sève, head of internal medicine at the Croix-Rousse hospital (Lyon).

"In 70 to 80% of cases, embolism is a complication of phlebitis of the lower limbs."

Pascal Sève, head of internal medicine at the Croix-Rousse hospital (Lyon)

For the remaining cases, it may be an embolism related to a clot formed in the upper limbs or directly in the lungs. But whatever the origin of the clot, pulmonary embolism is a life-threatening emergency. The obstruction of the pulmonary artery can, in fact, lead to a lack of oxygenation and heart failure. Between 5 and 10% of patients with embolism die.

It is therefore essential to go to the emergency room or call 15 when symptoms of respiratory discomfort, chest pain or bloody sputum occur. "If these signs are accompanied by symptoms of phlebitis, either edema of the leg, sudden pain, dilation of the veins and a change in the color of the leg, pulmonary embolism must be suspected", insists Prof. Benhamou .

What treatment?

To confirm the diagnosis of pulmonary embolism, a chest CT angiography may be done to show the presence of the clot, as well as a blood test. The management of pulmonary embolism (like phlebitis) involves dissolving the clot through the administration of anticoagulants by the intravenous or oral route.

In the most severe cases, removal of the thrombosis can be performed surgically. “After this phase of treatment, the challenge is to understand what may have triggered the embolism, and if possible to offer treatment,” explains Prof. Ygal Benhamou.

This could have occurred following surgery, prolonged immobilization, taking hormonal contraception or pregnancy. Genetic diseases causing bleeding disorders can also be the cause. "The association with cancer is, moreover, frequent and it is not uncommon to diagnose a cancerous disease during the assessment of venous thrombosis", adds the specialist.

But in a not insignificant number of cases, the cause of pulmonary embolism or phlebitis is not identified. These patients are then considered to be at high risk of recurrence. The latter is of the order of 10% the first year following the thrombosis, then 30-35% within five years. "The French recommendations recommend to prescribe an anticoagulant treatment and to reassess its value every six months, even every year", indicates Professor Benhamou.