Pulmonary embolisms

What is a pulmonary embolism?

A lung embolism refers to the occlusion of a pulmonary artery. Pulmonary arteries are blood vessels running from the heart to the lungs, where blood is being oxygenated.

Such vessels can be partially or completely closed by blood clots, for example, or by fat or foreign materials ( for example, cement used during a prosthesis operation). Usually, the embolus stems from a distant vessel and is washed into the pulmonary circulation. According to how severe the embolism is, it can quickly become a life-threatening emergency, causing cardiovascular failure and consequently death.

This is a relevant risk scenario mainly in the case of an embolism of a larger or several pulmonary arteries.

Because of the occlusion of the pulmonary artery, the right heart is forced to pump against a higher pressure. Meanwhile, the left heart no longer receives sufficient blood to keep the body and all vital organs (including the heart itself) supplied. Moreover, the blood is progressively depleted of vital oxygen.

Causes of lung embolism

In the majority of cases, a pulmonary embolism is due to a blood clot (thrombus). It often forms as part of a thrombosis affecting the deep veins of the leg or pelvis, with risk factors including bed confinement or immobilization following surgery or an accident.

Other risk factors are obesity, advanced age, previous embolisms or thromboses in the patient's own medical history or in the family, cancer, hormone therapy (e.g. oral contraceptive pill), pregnancy and postpartum period, foreign bodies such as vascular catheters, and congenital blood coagulation disorders.

Clots can become detached and will then be carried on with the regular blood flow from the distant vessels to the heart, from where they will enter the pulmonary arteries. As these branch out further, they become more and more narrow, eventually causing the embolus to become stuck and occlude the blood vessel.

Generally, the risk factors for embolism or thrombosis can be grouped as the so-called Virchow triad: slower blood flow, injury to the internal vessel walls, and changes in the composition of the blood all play a role.

More rarely, pulmonary embolism is caused by fatty conglomerates that can come off and enter the bloodstream, an example being during major surgery like the implantation of a knee or hip prosthesis.

Furthermore, air, amniotic fluid, foreign bodies (e.g. surgical cement), or various pieces of tissue (e.g. tumor cells, inflammatory material) can cause embolisms. But these cases are rare and are associated with very specific risk situations.

What are typical symptoms of pulmonary embolism?

Typical of a pulmonary embolism is a sudden, acute onset of symptoms.

Patients describe shortness of breath (dyspnea), faster breathing (tachypnea), and perhaps blue discoloration for example of the lips (cyanosis) due to a lack of oxygen.

Respiratory pain in the affected chest also occurs, together with coughing, sometimes with bloody discharge.

Cardiovascular impairment is marked by an accelerated heartbeat (tachycardia), which patients may perceive as palpitations. Dizziness or even brief unconsciousness (syncope) are possible as a result of a fall in blood pressure (hypotension). Neck veins may be congested.

If the case is particularly severe, circulatory failure develops within a short time, causing the patient to collapse and require resuscitation.

Medical diagnosis of pulmonary embolism

First of all, an urgent assessment must be made to find out whether the patient is in a stable condition (stable blood pressure) or if the patient is in an unstable and therefore life-threatening situation (need for resuscitation, shock, permanent hypotension with circulatory disturbances).

In a circulatory stable patient, the doctor treating the patient will first ask about risk factors for thrombosis or embolism.

In addition, heart rate, blood pressure and oxygen saturation are measured, as well as respiratory rate.

The physical examination may also show congested neck veins or signs of thrombosis in the leg (swelling, redness...).

Upon listening to the chest, altered heart sounds are a possibility, but they are not found in every patient.

The physician will essentially assess the so-called Wells score, which is a questionnaire that can be used to evaluate the likelihood of a pulmonary embolism in an individual patient. These questions include, for example, previous illnesses, risk factors like operations, and abnormalities in the physical examination.

Based on the patients' symptoms, which may also point to heart disease, an ECG is often done as well, and this may reveal certain abnormalities indicative of a pulmonary embolism. However, this is not very specific.

Additionally, a blood test is run, and certain coagulation parameters, typically D-dimers, are analyzed. While these are elevated in the presence of an embolism, normal values are usually not indicative of a pulmonary embolism. D-dimers can also be evaluated by a rapid test.

Also blood parameters that suggest cardiac stress, for example troponin or BNP, can be analyzed.

In a blood gas analysis, often a decreased oxygen level is apparent, as well as a decreased carbon dioxide level.

CT angiography is available to detect pulmonary embolism on imaging as well. During this exam, the patient is injected with contrast material, making the pulmonary arteries apparent on computed tomography. If an embolism is present, the vessel will show an abrupt stop as blood is no longer able to pass the obstructed area.

CT angiography remains one of the most essential examinations to confirm the diagnosis of pulmonary embolism.

In addition, echocardiography is possible. This involves an ultrasound examination of the heart, which can detect a right heart strain.

In some cases, for example those patients who cannot receive a contrast medium due to kidney damage, scintigraphy of the lungs can be performed. Using radioactively labeled drugs, the lungs' blood supply and ventilation can be visualized.

A chest X-ray is often performed, but pulmonary embolism is seldom diagnosed with certainty here.

For unstable patients, the decision whether or not CT angiography can be done has to be made on an individual basis and if in case it is not possible, rapid echocardiography can be carried out.

How is pulmonary embolism treated?

In the acute setting, a pulmonary embolism patient should receive oxygen through a nasal cannula or mask. Analgesics and sedatives may also be given if necessary. Anticoagulant drugs ("blood thinners") should be started rapidly (e.g., heparins). At the beginning, they are often injected directly into a vein or into the subcutaneous fatty tissue.

In the case of pulmonary embolism with no acute danger to life, so-called therapeutic anticoagulation is recommended after acute treatment. This is defined as the administration of blood-thinning, anticoagulant drugs, which patients can take as tablets and are given for about 3-6 months (vitamin K antagonists / coumarins or new / direct oral anticoagulants).

In the event of severe pulmonary embolisms, which are associated with serious symptoms and life-threatening circumstances, for example a required cardiopulmonary resuscitation, a procedure known as thrombolysis is performed. The purpose is to dissolve or remove the clot that is blocking the blood vessel. This may be achieved by delivering medication directly into the bloodstream (systemic lysis), but under certain circumstances it may also be performed by catheter treatments ( fragmentation and removal of the thrombus or direct delivery of a thrombolytic drug into the affected vessel) or by surgical interventions (extraction of the embolus by open surgery on the lung).

Should circulatory arrest ensue, immediate resuscitation (resuscitation) by all available means is necessary.

Which hospitals and physicians specialize in the treatment of pulmonary embolism?

Because an acute pulmonary embolism represents a medical emergency, any hospital providing acute care should be able to diagnose and treat it. Rapid recognition and prompt initiation of therapy are important to avoid a deterioration of symptoms, an increased threat to the patient's life, and secondary damage.

Medical specialists for pneumology / pulmonology (lung medicine) or angiology (vascular medicine) specialize in the treatment of pulmonary embolism. They work in close collaboration with cardiologists, or heart specialists, as well as cardiothoracic surgeons.

If you're in need of a doctor, you expect the best medical care possible. So of course patients are curious to find out what clinic to go to. As there is no objective way to answer this question and a legitimate doctor would never claim to be the best, patients must rely on a doctor's experience.

Let us help you find an expert for your condition. All listed doctors and clinics have been reviewed by us for their outstanding specialization in the field of lung embolism and are looking forward to your inquiry or wish for treatment.

Sources:

• www.amboss.com/de/wissen/lungenembolie/&;

• www.amboss.com/de/wissen/lungenembolie-amboss-sop

• www.herzstiftung.de/infos-zu-herzerkrankungen/herz-und-lunge/lungenembolie&;