Pulmonary embolism (PE) is a blockage in one of the pulmonary arteries in the lungs. It is a potentially life-threatening condition that can damage the lungs and other organs if not treated quickly. PE is most often caused by blood clots that travel from the legs or pelvis and lodge in the pulmonary arteries. Understanding the most common symptoms of PE is crucial for prompt diagnosis and treatment.
Some of the typical symptoms of PE include shortness of breath, chest pain, coughing, and leg swelling or pain. However, research indicates that the most frequent symptom found in patients with confirmed PEs is dyspnea, or shortness of breath.
One study published in the Archives of Internal Medicine examined the prevalence of various symptoms in 297 patients who were confirmed through imaging tests to have acute PEs. The results showed that shortness of breath was the most common symptom, occurring in 82% of patients. Chest pain was the second most common symptom at 49%, followed by cough at 20% and calf or leg pain at 18%.
Similarly, a systematic review published in the European Respiratory Review looked at data from over 6,000 patients across 26 studies. The analysis found dyspnea was again the most prevalent symptom, present in over 75% of patients with confirmed PEs. Meanwhile, pleuritic chest pain occurred in just under 50% of cases.
Understanding that shortness of breath is the most frequent PE symptom can help doctors diagnose the condition more rapidly. Patients who come to the emergency room or doctor’s office complaining of unexplained shortness of breath should be evaluated for possible PE.
Mechanism Behind Dyspnea in PE
So why is shortness of breath so common in pulmonary embolisms? The main mechanism relates to the blockage that the blood clot causes in the pulmonary arteries.
The clot obstructs blood flow through the lungs, which increases the strain on the right ventricle of the heart. The right ventricle is responsible for pumping blood to the lungs to be oxygenated. When blood flow is blocked, the right ventricle must work harder to push blood past the clot.
This increased strain on the right ventricle leads to pressure buildup in the pulmonary arteries, which in turn can cause fluid to leak into the lung tissue. This impairment in oxygen exchange is what produces shortness of breath and difficulty breathing.
In addition, the clot triggers the body’s inflammatory response, which can damage the lining of the lung tissue. This damage can further interfere with oxygenation and contribute to dyspnea.
Other Common Symptoms
While shortness of breath is the most frequent, there are several other symptoms that may occur with PE.
Chest Pain
Around 50% of patients with PE experience chest pain or discomfort. This type of chest pain often feels sharp or stabbing when taking a deep breath. It tends to get worse with deep breathing, coughing, or bending or twisting at the waist. The pain results from inflammation around the lung tissue.
Cough
Coughing occurs in approximately 1 in 5 cases of PE. It may start out dry and irritating and later produce sputum. Coughing results from irritation and inflammation in the lungs.
Leg Pain
Some patients experience pain or swelling in the leg, most often in the calf. This happens because most pulmonary emboli originate as blood clots in the deep veins of the legs, also known as deep vein thrombosis (DVT). If part of the clot breaks off and travels to the lungs, it can cause PE.
Risk Factors
There are a number of risk factors that can increase someone’s chances of developing a pulmonary embolism:
- Prolonged immobilization – after surgery, injury, or long trips
- Pregnancy
- Birth control pills or hormone replacement therapy
- Previous blood clots
- Obesity
- Smoking
- Cancer
- Heart failure
- Chronic inflammatory conditions like IBD
- Genetic blood clotting disorders
Older age also increases PE risk. The condition is most common in those over age 60.
Diagnosis
If pulmonary embolism is suspected based on risk factors and symptoms, the doctor will use various tests to confirm or rule out the diagnosis. These may include:
Blood Tests
Blood tests like D-dimer can help rule out PE. D-dimer is a protein fragment produced when a blood clot dissolves. High levels indicate increased clotting activity.
Chest X-Ray
A chest x-ray may show signs of fluid buildup or lung tissue damage, but can also appear normal. It is not sensitive enough to definitively diagnose PE.
CT Scan
A CT pulmonary angiogram, which injects dye into the bloodstream, can visualize blood clots in the lungs. This is the most accurate imaging test for diagnosing PE.
Ventilation/Perfusion Scan
A VQ scan looks at air and blood flow in the lungs. It can help confirm PE but is less accurate than CT.
Ultrasound
Ultrasound of the legs can help detect blood clots. About 90% of PEs originate as DVTs.
Treatment
Treatment for pulmonary embolism focuses on preventing further clot formation and resolving existing clots:
Anticoagulants
Blood thinners like heparin and warfarin prevent new clots from forming while the body slowly breaks down the existing clot.
Thrombolytics
Thrombolytic drugs like tPA can help dissolve blood clots quickly in life-threatening cases.
Blood Filters
A filter inserted into the vena cava can trap large clots and prevent them from traveling to the lungs.
Surgery
Surgical embolectomy to remove clots may be used in severe cases that do not respond to other treatments.
Most patients with PE require hospitalization for several days, along with careful monitoring of blood oxygen levels. After leaving the hospital, they must continue to take anticoagulant medication.
Complications
Some potential complications that can result from pulmonary embolism include:
- Pulmonary hypertension – increased blood pressure in the lungs
- Right ventricle dysfunction or strain
- Recurrence of blood clots
- Chronic thromboembolic pulmonary hypertension (CTEPH)
- Death – PE is fatal in about 5-10% of cases if not treated
Prevention
Steps to help prevent pulmonary embolism include:
- Early mobilization after surgery
- Compression stockings
- Avoiding long periods of immobilization during travel
- Staying active and exercising regularly
- Maintaining a healthy weight
- Quitting smoking
- Staying hydrated
Those at high risk may need to take preventive anticoagulant medication.
Conclusion
In summary, the most frequent symptom found in patients with confirmed pulmonary emboli is shortness of breath or dyspnea. This occurs because blood clots obstruct blood flow through the lungs, causing fluid buildup and inflammation that impairs oxygen exchange.
While dyspnea is the most common symptom, chest pain, cough, and leg pain can also occur. Diagnosis relies on imaging tests like CT scans. Treatment focuses on anticoagulant medications and possibly thrombolytics or surgery in severe cases.
Raising awareness that unexplained shortness of breath may indicate PE can help prompt rapid diagnosis and lifesaving treatment. Those at higher risk should take steps to prevent blood clot formation.
