An embolus is usually a blood clot (thrombus). Still, it can also be fat, amniotic fluid (amniotic fluid), bone marrow, a tumor particle, or an air bubble that travels with the blood and blocks a vessel. A pulmo embolism is a sudden blockage of a pulmonary artery with an embolus.
PULMONARY EMBOLISM: General | Causes of pulmonary embolism | Risk Factors | Symptoms | Diagnosis | Forecast | Prevention | Treatment | Questions and Answers | Sources/references
Usually, the unaffected arteries still supply the affected lung area with enough blood to prevent tissue death. However, if massive vessels become blocked or the patient has pre-existing lung disease, the blood supply may be insufficient to prevent tissue death. About 10 percent of patients with pulmonary embolism die of more or less lung tissue; this is called a pulmonary infarction.
If the body breaks down small clots quickly, damage is minimal. Large clots take much longer to break down, making the damage more significant. Large clots can cause sudden death.
Causes of pulmonary embolism
The most common type of pulmonary embolus is a blood clot, usually in a vein in the leg or pelvis. Blood clots tend to form when the blood flows slowly or stops at all, and this can happen in the leg veins of a person who remains in the same position for a long time.
Image: AI display of pulmonary embolism
When it starts to move again, the blood clot can break off. Clots in the veins of the hands or the suitable cavities of the heart are much less common. Once a clot breaks off in a vein and is carried away by the blood, it usually travels to the lungs.
What causes a tendency to blood clots?
The cause of blood clots can sometimes not be determined, but there are often apparent factors that increase the tendency for clots to form. Among them are:
- operations,
- long-term lying in bed or physical inactivity (e.g., sitting during long car or plane journeys),
- stroke,
Image: showing the formation of a blood clot
- heart attack,
- obesity,
- fracture of the hip or leg,
- increased tendency of the blood to clot (e.g., in certain types of cancer, while taking birth control pills, and in the case of a hereditary deficiency of a blood clotting inhibitor).
Another type of emboli is formed from fat that escapes into the blood from the bone marrow when a bone breaks. An embolus can also form from the amniotic fluid (amniotic fluid) during childbirth. However, both fat and amniotic emboli are rare.
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They usually stop in small vessels, e.g., pulmonary arterioles and capillaries; acute respiratory distress syndrome may develop if many such vessels are blocked.
Symptoms
Small emboli may not cause symptoms, but most cause shortness of breath. This may be the only symptom, significantly, if a pulmonary infarction does not develop. Often, the breathing is speedy; the patient feels anxious (anxiety) or restless and may appear to be having an anxiety attack. He may feel a sharp pain in his chest, especially if he breathes deeply, called pleuritic chest pain.
Video content: What are the warning signs of pulmoembolism?
For some people, the first symptoms may be dizziness, fainting, or a seizure. These symptoms usually occur because the heart suddenly stops beating, supplying the brain and other organs with well-oxygenated blood. Irregular heartbeats may also occur. Patients with blockage of one or more large pulmonary vessels often have bluish skin (cyanosis) and may die suddenly.
Pulmonary infarction causes cough, bloody sputum, sharp pain in the chest while breathing, and fever. Symptoms of a pulmonary embolism usually appear suddenly, while symptoms of a pulmonary infarction occur within a few hours. The symptoms of a heart attack often last for several days but are usually milder day by day.
Image: what does a pulmonary infarction look like?
In people who experience repeated episodes of small pulmonary emboli, symptoms such as chronic shortness of breath, swelling of the ankles or legs, and weakness, as a rule, develop gradually over weeks, months, or years.
Diagnosis
The doctor thinks of a pulmonary embolism based on the patient's symptoms and factors that increase the tendency to it. Specific tests are often required to confirm the diagnosis.
Rentgenogram of chest organs can show barely noticeable changes in pulmonary vessels, embolismolism, and signs of pulmonary infarction. However, the results of such imaging are often expected, and even if they are not, they can rarely confirm pulmonary embolism.
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An electrocardiogram may show abnormalities, but these are often transient and can only support the assumption of pulmonary embolism.
Perfusion scintigraphy of the lungs is often performed. A small dose of radioactive material injected into a vein travels to the lungs, showing the general pattern of pulmonary blood flow (perfusion). Parts not generally supplied with blood are dark in the image because radioactive particles do not reach them. A typical result of such scintigraphy means that the patient has no significant blockage in the blood vessel. Still, an abnormal result can be caused by other causes besides pulmonary embolism.
Usually, perfusion scintigraphy is performed simultaneously with ventilation scintigraphy of the lungs. The subject inhales a harmless gas containing traces of a radioactive substance distributed throughout the lungs' tiny sacs (alveoli). The camera shows the parts where oxygen exchange takes place. The doctor can usually tell if the patient has a pulmonary embolism by comparing this image with the blood flow pattern on the perfusion scintigram. The embolized part is usually ventilated (has normal ventilation) but has insufficient blood supply (has reduced perfusion).
Pulmonary arteriography is the most accurate way to diagnose pulmonary embolism, but it is not without risks and is more uncomfortable than other tests. The subject is injected with an X-ray contrast medium that flows into the pulmonary arteries. On an X-ray, a pulmonary embolism appears as a blockage in an artery.
Further tests may be needed to determine where the embolus initially developed.
Forecast
The likelihood that a patient will die from a pulmonary embolism depends on the size of the embolus, the size and number of blocked pulmonary arteries, and the patient's general health. Anyone with severe heart or lung problems is at greater risk of an embolism. Patients with normal heart and lung function usually survive if the embolus does not block more than half of the pulmonary vessels. Fatal pulmonary embolism usually results in death within 1 to 2 hours.
About half of patients with untreated pulmonary embolism will experience a recurrence in the future. Up to half of recurrences are fatal. Treatment with drugs that inhibit blood clotting (anticoagulants) reduces the recurrence rate to about 1 in 20.
Prevention
In people at risk of pulmonary embolism, it is necessary to try to prevent the formation of blood clots in the veins. In postoperative patients - especially the elderly - elastic stockings, leg exercises, getting out of bed, and starting to move as soon as possible reduce the risk of clots. Compression stockings are designed to maintain blood flow, reduce the formation of clots in the legs, and thus reduce the frequency of pulmonary embolism.
Video content: protection against the formation of blood clots in the lungs and legs.
To reduce the risk of blood clots in the veins, the sword is used after operations with anticoagulant heparin. It is injected in small doses just under the patient's skin immediately before and seven days after surgery. Heparin can cause bleeding and slow healing, so it is only given to people who are at high risk of clotting; these include patients with heart failure, shock, chronic lung disease, the obese, and those with a history of blood clots. Heparin is not used in operations on the spinal cord and brain because the risk of bleeding in these areas is too significant. Small doses of heparin are also given to those patients in hospitals who are at high risk of pulmonary embolism (even if they have not been operated on).
Dextran, which must be injected intravenously, also helps prevent blood clots. Like heparin, it can cause bleeding. During certain operations in which the risk of blood clots is exceptionally high (for example, hip fracture repair or replacement of this joint), patients can be given warfarin tablets. Treatment with warfarin may be necessary for several weeks or months.
Treatment
Treatment of pulmonary embolism begins with using oxygen and, if necessary, analgesics. Anticoagulants, such as heparin, are given to prevent an existing blood clot from growing and new ones from forming. To achieve a quick effect, the patient receives heparin intravenously. The dose should be adjusted carefully. Next comes warfarin, which prevents clotting but starts working more slowly. Since it can be consumed, it is suitable for long-term use. Heparin and warfarin are given together for 5 to 7 days until blood tests show that warfarin is effectively preventing clotting.
The duration of anticoagulant treatment depends on the patient's situation. If pulmonary embolism is caused by a previous predisposing factor, e.g., surgery, treatment lasts 2 to 3 months. If the cause is a longer-term problem, the treatment usually lasts 3 to 6 months, but sometimes it takes a lifetime.
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While taking warfarin, the patient must have regular blood tests to show whether the dose needs to be adjusted. Patients who are at risk of death from pulmonary embolism may benefit from two other options: thrombolytic therapy or surgery. Thrombolytics (medicines that break up blood clots), e.g., streptokinase, urokinase, or tissue plasminogen activator, can help. However, these drugs should not be given to people who have undergone surgery in the last ten days, pregnant women, recent stroke patients, and those who are prone to excessive bleeding. Surgery is sometimes necessary to save a patient with severe pulmonary embolism. Pulmonary embolectomy (removal of an embolus from a pulmonary artery) can save a life.
If emboli recur despite all preventive treatment, or if anticoagulants cause heavy bleeding, a filter can be surgically inserted into the large vena cava (the central vein leading from the legs of the pelvis to the right side of the heart). Clots usually originate from the legs or pelvis, and such a filter prevents them from drifting into the pulmonary artery.
Questions and answers
What are the warning signs of pulmonary embolism?
- Shortness of breath, which may appear suddenly.
- Pain in the chest can get worse when you breathe in and is as bad as having a heart attack.
- Dizziness or fainting due to a sudden drop in blood pressure.
- Cough that may contain blood[1].
Is pulmonary embolism life-threatening?
pulmonary embolism can be life-threatening, especially if left untreated. It can cause several complications, including cardiac arrest, when the heart suddenly stops[2].
Can a pulmonary embolism go away?
In most cases, we hope our body will eventually dissolve the clot and repair the problem automatically. If not, more drastic measures may need to be taken. During hospitalization, the drug is administered by injection, and later, after discharge, treatment is carried out with the help of tablets[3].
How do I know if I have an embolism?
The most common symptoms are:
Sudden shortness of breath (most common)
Chest pain (usually worse with breathing)
Feeling anxious[4].
Sources and references
An extensive health manual for home use, Youth Book Publishing House
- Pulmonary Embolism Symptoms and Diagnosis - https://www.lung.org
- pulmonary embolism - https://www.pennmedicine.org
- Treating Pulmonary Embolism - https://www.lung.org
- Dyspnea/Shortness of Breath - https://www.brighamandwomens.org
