Pulmonary Embolism – Causes, Symptoms & Therapy

In the case of a pulmonary embolism, subsequent parts of the lungs are no longer supplied with sufficient blood as a result of this vascular occlusion.

As a result, depending on the size of the closed area, more or less extensive parts of the lungs no longer participate in the actual function, namely the saturation of the blood with oxygen.

There is a drop in oxygen concentration and, as a result, a possible lack of oxygen in other organs or areas of the body.

Another major problem that can often develop very quickly and very dangerously as a result of a pulmonary embolism is overstraining the heart muscle .

The right ventricle, in particular, has to pump against the blockage of the pulmonary circulation directly downstream – the same amount of blood suddenly has to go through a tube that is perhaps only half as thick. Due to this overload of the heart muscle, decompensation can quickly occur, which can be life-threatening for the patient.

causes

In most cases, the cause of a pulmonary embolism is a deep leg or pelvic vein thrombosis . A thrombosis is a slowly developing occlusion of a vein, i.e. a vessel that is supposed to carry blood that normally flows very slowly back to the heart.Since veins themselves, unlike arteries, do not have any muscles and the pumping action of the heart can hardly develop any power at this late point in the blood circulation, people need other mechanisms to keep the venous blood moving in the direction of the heart. This is normally the muscles of the legs, which literally squeeze the veins between the individual muscle groups when walking.

In the case of prolonged immobility, such as can occur in the hospital after an operation, on long bus journeys or long-haul flights, this pumping effect falls by the wayside, the blood stays too long in the same place within the vein and clots there. These clots form occlusions. Varicose veins , which many people have on their lower legs, also increase the risk of venous thrombosis.

This is where the pulmonary embolism comes into play: The thrombi in the leg veins are not fixed, but can be washed away at any time when the leg starts moving again. However, the route taken by these thrombi is clearly defined by the bloodstream: First, the blood vessels become larger and larger, then the thrombus enters the right atrium, from there into the right ventricle and from there into the pulmonary vascular system. Here the vessels narrow again – until the thrombus, which at this point in time is referred to as an embolus, gets stuck somewhere.

symptoms and course

The symptoms of a pulmonary embolism depend on the size of the blood clot. When the pulmonary embolism is relatively small, it usually causes only a brief cough . With larger pulmonary embolisms, however, greater symptoms occur.

These symptoms can sometimes appear suddenly and range from sudden chest pain when inhaling, shortness of breath and sometimes even coughing up blood. Accompanying symptoms are sweating and anxiety in connection with a faster pulse .

Lack of oxygen also leads to discoloration of fingernails and lips and can even lead to unconsciousness. If the blood clot slowly dissolves and is washed away in stages, the symptoms can also occur in phases.

The symptoms of a pulmonary embolism are often very unspecific, which makes the diagnosis difficult and makes the clinical picture so dangerous as a “chameleon of cardiology”. Some of those affected complain of chest pains as in a heart attack , shortness of breath and coughing with possibly bloody sputum.

Others have hardly any symptoms, only a closer examination reveals accelerated breathing and a racing pulse or congested veins in the neck. The latter result from the overload situation of the right heart, which is no longer able to pump the blood supplied to it. It is therefore an absolute emergency symptom.

Smaller pulmonary embolisms often occur without symptoms or with rather atypical symptoms such as a brief collapse. Large vascular occlusions in the lungs can lead to circulatory collapse and death within seconds.

Diagnose

The first step when a pulmonary embolism is suspected is usually for a doctor to measure your pulse and blood pressure and listen to your lungs and heart sounds. Tests of blood samples then provide further important information. If certain values ​​are increased, this strengthens the suspicion of a pulmonary embolism. While measuring the cardiac currents using an ECG or an X-ray of the lungs can also only provide indications, a clear diagnosis is only possible by showing the pulmonary arteries.

Such an examination of the vessels in the lungs, called angiography, can be carried out either by computer tomography or perfusion scintigraphy. With this, the patient is injected with a substance that contains a small amount of radioactive substances. This enables the visualization of the blood flow in the lungs and thus the accurate detection of a possible pulmonary embolism. Computed tomography also shows the vessels of the lungs, although different X-ray images are taken from different directions. Cross-sectional images are then generated from these recordings, which provide a precise overview of the blood circulation conditions in the lungs.

complications

A pulmonary embolism can cause life-threatening complications. The poor circulation in the lungs can lead to pleurisy . As a result of pleurisy, shortness of breath, thickening and adhesions of the pleural layers and severe pain sometimes occur. A pulmonary embolism can also cause a pulmonary infarction. At the same time, the undersupplied lung tissue dies. A heart attack usually also causes pneumonia, which in turn is associated with life-threatening complications.

In about four percent of those affected, a chronic increase in pressure in the pulmonary circulation occurs after a pulmonary embolism. Possible consequences are right heart failure and an overall limited physical performance. The intensive medical treatment of lung therapy is also associated with risks. With artificial respiration there is a risk of pneumonia.

In addition, a catheter can cause injuries in the area of ​​the lungs and thus lead, for example, to serious pulmonary bleeding or functional impairment of the lungs. Drug treatment can have side effects and interactions. Allergic reactions can also occur if any allergies are not adequately clarified beforehand.

treatment and therapy

If a pulmonary embolism is suspected, emergency medical care must be sought immediately. Until then, those affected should be placed in a position that is as still as possible.The respective treatment strategy depends on the severity of the pulmonary embolism. Intensive medical monitoring is usually necessary.

In less severe cases, the therapy is primarily aimed at treating the vascular blockage in the pulmonary vessels (embolus). Patients are given anticoagulants ( heparin ) to thin the blood and prevent the embolus from further enlarging.

Depending on the degree of impairment of the right heart, medicinal dissolution (lysis therapy) of the blood clot can be considered. However, this carries the risk of internal bleeding in other organs.

It is also possible to break up a pulmonary embolus with a minimally invasive catheter.

prevention

To prevent a pulmonary embolism, it is advisable to always take medicinal thrombosis prophylaxis for any lengthy periods of immobilization (flights, bus trips, long periods of stay). This consists of a short injection into the subcutaneous fatty tissue.