Pulmonary embolism: definition
Pulmonary embolism is obstruction of one or both of the pulmonary arteries by a blood clot (thrombosis). It has mostly migrated from a vein in the lower limbs reached by phlebitis also called venous thrombosis (70% of cases *). These two events - embolism and thrombosis - are part of the same disease, venous thromboembolism (VTE).
Depending on the level of obstruction, and the diameter of the clot, or any part of the lung is deprived of blood. This obstruction results in a subsequent heart block with acute respiratory failure and heart failure that can be fatal: that massive pulmonary embolism with cardiac arrest immediately.
Pulmonary embolism: risks and consequences
The venous thromboembolic disease affects about 150,000 people per year. Following him, pulmonary embolism (PE) causes 20,000 deaths; this is the third leading cause of cardiovascular death after myocardial infarction and stroke (source: interviews Bichat, 2010).
The risk depends on the importance of the private territory of pulmonary blood, so the percentage of obstruction by clots or migrants. Advanced age is a risk factor for death.
Only 10% of EP are fatal in one hour. But in half of the cases they cause insufficient heart more or less well tolerated in time and absolutely require good care. A distance embolism treated, the risk of pulmonary hypertension is 5% *.
Pulmonary embolism: origins and causes
One or more blood clots in the pulmonary arteries block during passage of the blood to be oxygenated. Lacking the blood blocked upstream, the heart fails to work properly, then it should just provide an extra effort to correct this lack of blood throughout the body.
About 70% of cases of pulmonary embolism are caused by the migration of a clot from phlebitis of the lower limbs (DVT). To meet and consider embolism, it is still necessary that the phlebitis of the legs occurs, it is the case for less than one out of four *. More often we are dealing with phlebitis of the pelvis or the inferior vena cava (large vein in the abdomen) totally invisible. But in this case the risk of embolism is massive high.
Venous clots of thromboembolic disease appear particularly susceptible individuals by genetic background (personal or family history) or suffering from cancer. Genetic disorders of coagulation causes are increasingly recognized in this disease.
But the great cause of phlebitis venous stasis. First by bed rest, he must follow an illness or surgery; then by poor circulation or varicose field. Phlebitis is also feared as a cast of the lower limbs or in a long-haul air travel in a dry atmosphere (dehydration makes the blood less fluid), even if it is followed by a trek at altitude dehydration persistence (total effort and the dry atmosphere). All situations causing hyperviscosity are at risk of thrombosis (caillotage), so pulmonary embolism: smoking, obesity, pregnancy, childbirth and after, heart failure, oral contraception days.
Venous clot breaks off more easily since it was formed less than 5 days and it moves at sunrise after prolonged bed rest (home or hospital) for example.
Signs and symptoms of pulmonary embolism
Pulmonary embolism is often understated: there must be at least 30 to 40% of the pulmonary arteries to be clogged that the signs are visible. Therefore, pulmonary embolisms are rarely diagnosed. Only "big" are noticed. The diagnosis is made during a pulmonary imaging (CT, MRI) for another reason.
The classic table combines a sudden difficulty breathing (dyspnea) with a sharp chest pain, like a stitch or a dagger that increases on inspiration. Shortness of breath sudden unexplained is the only sign still present (pain may be missing). It may be added tachycardia (rapid heartbeat), unexplained anxiety, cough, fever 38%, cyanosis of the extremities (bluish fingers), one or coughing up blood (hemoptysis).
Chest pain stabbing and difficulty breathing enough to evoke a pulmonary embolism even if one is not aware of phlebitis. The urgent consultation of doctor or emergency services if necessary.
Pulmonary embolism are more frequent in winter, due to an increase in clotting related to winter infections, reduced physical activity and venous constriction caused by the cold.
Not to be confused with what?
Acute bronchitis, pericarditis (inflammation of the lining around the heart), asthma, myocardial infarction, pulmonary disease or infection of the gallbladder (cholecystitis) can simulate a pulmonary embolism.
Will it prevent a pulmonary embolism?
Yes. This is identical to that of the lower limb vein thrombosis.
Early up after surgery or childbirth, the active mobilization of the lower limbs, wearing stockings or compression socks; and prescription of heparin called "low molecular weight" (LMWH) in high-risk situations: bed rest, plaster, surgery.
In pul monaires recurrent embolism, it can be a filter in the inferior vena cava to prevent the rise of any clots from leg veins.
When to call the doctor?
Emergency after the occurrence of sudden unexplained like a stitch or stabbing chest pain; especially if it is accompanied by difficulty breathing, coughing and discomfort. But also occurs when an unexplained respiratory difficulty.
How to prepare the consultation?
Summarize his treatment, the events of recent weeks (phlebitis or circumstances conducive to phlebitis), provide medical and possibly his last book electrocardiogram.
What does the doctor facing a suspicion of pulmonary embolism?
It confirms the signs suggestive of pulmonary embolism and evaluates its general tolerance. He can do an electrocardiogram to add arguments to the diagnosis.
Hospitalization is required to confirm and treat pulmonary embolism. The electrocardiogram (ECG), chest radiograph, a study of blood gases, blood levels of certain markers ("D-dimer") and a Doppler ultrasound of the lower limbs are always facts.
Examinations have certainty as appropriate and availability: a lung scan, angio-CT, angiography (opacification of vessels) or transcardially ultrasound. Support resuscitation depends on the severity of the embolism.
Once the diagnosis is confirmed, it is possible to surgically remove a large clot or destroy thrombolysis. In all cases, the treated venous thromboembolic disease, causing embolism, by anti-coagulants (heparin) to effective dose. That pose a risk of bleeding, imposing strict controls and good patient compliance.
Due to the high risk of recurrence, anticoagulation was continued several months with venous contention, changing heparin by anti-vitamin K or a new class of anti-coagulant: the "anti-Xa" type or "anti-IIa." Prescription and monitoring is specialist business.