PULMONARY EMBOLIA: causes, symptoms of pulmonary thromboembolism

L'pulmonary embolism is a partial or total obstruction of thepulmonary artery and / or its ramifications. Since this is a serious and risky pathology, it is advisable not to underestimate the symptoms and immediately consult a doctor or a health facility to reduce the risk of serious complications.
This text is not intended to replace the necessary patient-doctor relationship, but to simplify, through an immediate language, the characteristics, causes, symptoms and therapy of pulmonary embolism.

Pulmonary embolism

Thrombosis and embolism

Thrombosis ed embolism they do not represent the same pathology, but are often confused. More precisely, (pulmonary) embolism is in most cases a serious complication of a thrombosis: in this case we speak of pulmonary thromboembolism.

What is a thrombus? A thrombus is an obstruction of a vein you hate an artery due to a clot of blood that adheres to the walls of the vein (or artery) and causes partial or total obstruction with consequent interruption of normal blood flow. Depending on whether it is a vein or an artery (less frequent) it will take the name of venous thrombosis or arterial thrombosis.

What is an embolus? An embolus is a part of the main thrombotic mass that detaches from its point of origin (venous or arterial wall) and begins to circulate in the bloodstream. These thrombotic fragments (emboli) are very dangerous as they can reach vessels of smaller diameter, partially or totally obstructing the flow of blood, generating ischemia. If the obstruction caused by the embolus occurs in the pulmonary vessels, it is pulmonary ischemia (temporary lack of blood in the lungs).

Respiratory and circulatory system

To easily understand pulmonary embolism, a few notes on the respiratory and circulatory systems are necessary.
The respiratory system is composed of the upper respiratory tract (nose, pharynx, larynx), the lower respiratory tract (trachea and bronchi) and the lungs.
The inhaled air passes through the airways to get to the lungs. In the lungs, and more precisely in the alveoli, gas exchange takes place with the blood, which becomes charged with oxygen and is transported to the left atrium of the heart through the pulmonary vein.

The circulatory system consists of the heart, arteries, veins and capillaries.
Arteries are distinguished from veins because oxygenated blood flows through them and reaches the whole organism, while veins return blood poor in oxygen and rich in carbon dioxide to the heart. Pulmonary veins and arteries are an exception.

In fact, oxygen-rich blood passes through the pulmonary vein.
The pulmonary artery, on the other hand, which leads the blood from the heart to the lungs, does not carry oxygenated blood, but is rich in carbon dioxide.
The circulation of the blood can be divided into two circles: the small circle, which concerns the exchange between the lungs and the heart (pulmonary circulation) and the large circle (systemic circulation) in which the heart irrigates the whole organism.

Causes of pulmonary embolism

As already mentioned, embolism is a serious complication of thrombosis. It is called thromboembolism or pulmonary thrombosis because the embolus is part of the thrombotic material that has developed into thrombosis. In most cases, the thrombus starts from a thrombosis of the lower limbs (specifically deep vein thrombosis) and, going up towards the heart, obstructs a blood vessel in the lung.

The embolus can be constituted by a blood clot when it is generated by a deep vein thrombosis (95% of the cases) or it can present itself as an air bubble, of liquid, of tumor mass, of fat in the remaining cases. If the embolus obstructs the pulmonary artery, the amount of blood in the lungs decreases, with serious consequences (massive pulmonary embolism, pulmonary ischemia, pulmonary aneurysm, up to death, in the most dramatic cases).
Since pulmonary embolism is in most cases a serious complication of deep vein thrombosis, it is necessary to know (and prevent, where possible) the causes of the latter.

Prolonged physical inactivity, damage to the venous walls and hypercoagulability are the possible causes of a deep vein thrombosis.
Physical inactivity means different situations: from those who spend many hours sitting (for work, for a long journey by car or plane) to those who are forced to stay in a fixed position or immobilized in bed due to operations undergone or for other pathological conditions.

If, on the other hand, a venous wall is damaged, following a bone fracture for example, clots form locally to stop the bleeding. A portion (embolus) can detach from this clot and begin to flow through the veins until it reaches the heart and lungs.
Finally, hypercoagulability (the tendency to form blood clots) may depend on some tumors, on genetic characteristics of thrombophilia, on heart failure or on hypertension.

Risk factors for pulmonary thromboembolism

Certain behaviors and habits can contribute to the onset of thrombosis of the lower limbs.
A life that is too sedentary, work in a static position, old age, episodes of embolism or thrombosis in the family, being overweight, obesity, pregnancy, smoking and oral contraceptives are all risk factors that should not be underestimate.

Symptoms of pulmonary embolism

The symptoms with which a pulmonary embolism occurs are varied (dyspnoea, severe chest pain, cough with blood, cyanosis, arrhythmia) and it is advisable not to neglect them in order to intervene immediately.

Dyspnea (difficulty in breathing) can manifest itself in mild, apparently negligible forms, up to severe respiratory failure with the appearance of cyanosis.
Cyanosis is caused by the bluish discoloration of the extremities of the body, such as hands, feet, lips, ears due to poor oxygenation of the blood.
The cough is dry, with possible bloody or blood mixed with phlegm.

Finally, cardiac arrhythmia is an alteration of the normal heart rhythm and beat.
When the walls of the pulmonary arteries narrow or remain occluded, pulmonary hypertension can occur: a prolonged increase in blood pressure in the lungs.

The symptoms of pulmonary hypertension coincide with those of pulmonary embolism (being in some cases a direct consequence of this pathology) and are: shortness of breath (dyspnea), feeling of fainting, pain or feeling of strong pressure in the chest, dizziness.
It is essential not to neglect or underestimate these symptoms, even if they occur in a mild form, as in the most severe cases it can lead to pulmonary infarction due to the persistent lack of oxygen in the lungs.

Pulmonary Embolism Diagnosis

Symptoms of pulmonary embolism can be confused with other diseases, so an effective and accurate diagnosis is necessary.
The Wells criteria facilitate a correct diagnosis and identification of the best strategy by evaluating each individual case through a score that allows to classify patients at high and low risk of pulmonary embolism.

Subsequently, through blood tests it is possible to identify the D-dimer, which increases to counteract an abnormal process of clotting in the blood.
The cause of the high D-dimer is therefore a higher than normal coagulation activity, due to thromboembolic disorders.

When pulmonary embolism is suspected, it is essential to check the lower limbs as deep vein thrombosis often also creates visible swelling in the lower limbs. To analyze the situation of the blood vessels, ultrasound Doppler of the lower limbs is necessary, capable of detecting any deep vein thrombosis.
CT angiography (angiography with computed tomographic acquisition) is an extremely effective examination as it allows you to directly view the embolus, or emboli, in the pulmonary circulation.

Lung scintigraphy analyzes ventilatory capacity and lung perfusion. First the patient inhales a radioactive gaseous substance to check the ventilatory capacity and then a radioactive substance is injected into the vein which shows how the blood reaches the lungs through the blood vessels.
The echocardiogram analyzes the right ventricle which, in the case of pulmonary hypertension, can lead to severe decompensation, also excluding the possibility of a myocardial (heart) infarction.

Pulmonary embolism therapy

Prompt intervention with adequate therapy is essential for patient survival. The therapy indicated below refers to a pulmonary embolism caused by deep vein thrombosis.

The most frequent and effective therapy is pharmacological, specifically the use of anticoagulants (heparin, warfarin) to thin the blood, interrupting or slowing down the coagulation process.
In the most serious cases, such as massive pulmonary embolism (a situation in which more than 50% of the pulmonary circulation is compromised), surgery is performed with extremely risky and invasive operations (embolectomy and caval filtering) and with thrombolytic drugs that allow clots to dissolve of blood but with dangerous side effects, such as bleeding.

Anticoagulant therapy usually begins with intravenous heparin. After the treatment with heparin, the therapy follows with the taking of warfarin orally.

The duration of therapy with oral anticoagulant is variable and depends on the characteristics of the individual patient, furthermore constant blood checks are necessary, in particular the INR, that is the clotting time, to determine a correct dosage of the drug.
As the weeks go by and the patient stabilizes about the therapy, the checks become less frequent.

During therapy it is very important to follow some precautions: do not change the diet abruptly but reduce the intake of foods with a high content of vitamin K, as it partially invalidates the effects of the anticoagulant.
It is advisable not to take alcohol and spirits, not to eat foods rich in fat, to stop taking hormonal therapies such as oral contraceptive, not to smoke and to contact your doctor for any other drug and / or natural supplement you want. to hire.

Consequences of pulmonary thromboembolism

The consequences of a pulmonary embolism can be very serious: pulmonary haemorrhage, pulmonary hypertension, cardiovascular collapse, heart failure, pulmonary ischemia. In the most dramatic cases, embolism can lead to heart attack and lung infarction is dangerous as it consists in necrosis of the lung tissue, even causing death.

Pulmonary embolism recovery and mortality

Although it is an extremely serious pathology, the promptness of intervention and the pharmacological treatment allow in most cases the recovery of the patient. When surgery is required, the probability that the patient will not survive increases considerably, both due to the severity of the initial situation and the invasiveness of the operation itself.

The mortality rate from pulmonary embolism depends on various factors, such as: the patient's age, specific pathologies, the possibility of relapse and the secondary consequences of the embolism itself on the lungs, heart, circulatory and respiratory systems of the patient.


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