Pulmonary Embolism – Diagnosis and Treatment
Diagnosis
Blood Sample Analysis
Doctors use blood tests to look for signs of a blood clot, especially by measuring a protein fragment called D-dimer.
High D-dimer levels can suggest clot formation in the body, but this can happen for many reasons, not just a pulmonary embolism.
Doctors also use blood tests to check if blood oxygen levels are lower than normal, which can occur with a blockage in the lung arteries.
Sometimes, these tests help find out if a person has genetic factors that make their blood more likely to clot.
| Test | What It Checks For | Significance |
|---|---|---|
| D-dimer | Clot breakdown products | High = possible clot formation |
| Blood gases | Oxygen & carbon dioxide levels | Low Oโ = possible lung blood clots |
| Clotting disorders | Genetic risk for blood clots | Can explain frequent clotting |
Chest Imaging
A standard chest X-ray helps doctors rule out other illnesses that have symptoms similar to a pulmonary embolism, like lung infection or heart failure. Chest X-rays use low doses of radiation to show pictures of the chest, heart, and lungs.
Chest X-rays cannot directly detect a pulmonary embolism; sometimes results are normal even when an embolism is present.
Sound Wave Vein Testing
Doppler ultrasound uses sound waves to look for blood clots in the veins, usually in the legs.
A small device called a transducer moves over the skin, sending out sound waves and recording the echoes as they bounce off blood cells.
This test shows if there is a blockage that might break free and travel to the lungs. If doctors find a clot, they can start treatment quickly.
Advanced CT Imaging of Pulmonary Arteries
CT pulmonary angiography gives a detailed look at the blood vessels in the lungs using X-ray technology and computer imaging.
Before the scan, doctors may give a contrast dye through a vein in the arm to make the blood vessels stand out.
This test can directly confirm the presence of a pulmonary embolism within the lung arteries. It also helps rule out other conditions that cause similar symptoms.
Advantages:
- Fast and accurate
- Shows blood clots in great detail
Note: People with kidney problems or allergies to contrast material may not be good candidates for this test.
Checking Air and Blood Flow: V/Q Scan
Sometimes, a ventilation-perfusion (V/Q) scan is needed for people who cannot have CT scans. This test uses a small amount of radioactive material to compare air flow (ventilation) with blood flow (perfusion) in the lungs.
If certain areas have good air flow but poor blood supply, this can be a sign of a pulmonary embolism. The V/Q scan does not use iodine-based contrast dye, so it is safer for people with kidney disease or dye allergies.
Pros:
- Helpful for those who cannot have a CT scan
- Can identify mismatches between air and blood flow
Dye-Based Lung Vessel Imaging
A pulmonary angiogram gives a clear picture of the blood flow in the lung arteries. During this test, doctors thread a thin tube called a catheter through a vein in the leg or arm up into the lung arteries.
Doctors inject a special dye and take X-rays as the dye flows through the arteries.
This test is the most accurate for spotting a pulmonary embolism, but it brings certain risks, such as temporary heart rhythm changes and possible kidney effects from the dye.
Because this test is invasive, doctors usually use it only when other imaging methods do not give clear results.
Details:
- Most precise test but higher risk
- Shows real-time movement of blood in the lungs
MRI Imaging for Blood Clots
MRI, or magnetic resonance imaging, uses strong magnets and radio waves to create detailed images of body tissues, including blood vessels.
MRI does not use radiation, so doctors often choose it for pregnant women or people with kidney problems who cannot receive contrast dye.
MRI can find blockages in lung arteries, but doctors use it less often than CT scans or V/Q scans because it takes longer and is not always available in emergencies.
When MRI Is Used:
- For people who should not have radiation
- If kidney safety is a concern
Summary Table: Lung Blood Clot Diagnostic Tests
| Method | Invasive | Detects PE directly? | Notes |
|---|---|---|---|
| Blood tests (D-dimer, oxygen levels) | No | Indirect | Screens for clot and low oxygen |
| Chest X-ray | No | No | Rules out other conditions |
| Doppler ultrasound | No | Indirect | Finds leg or arm clots as possible source |
| CT pulmonary angiography | No | Yes | Most common, detailed, fast |
| Ventilation-perfusion (V/Q) scan | No | Yes | Used when CT scan is not possible |
| Pulmonary angiogram | Yes | Yes | Most accurate, more risks, used less often |
| MRI | No | Yes | Used for special groups, less common |
Treatment
Medications for Blood Clots
The main goal of using medicines is to stop blood clots from getting larger and prevent new ones from forming. Anticoagulants are the most commonly used drugs for this.
Doctors sometimes call them blood thinners, though they do not actually make the blood thinner but change how it clots. Some common anticoagulant medicines are:
Doctors often give unfractionated heparin through an IV or injection for quick action, sometimes until oral medicines begin to work. Direct oral anticoagulants (DOACs) act fast and may have fewer side effects and food interactions than warfarin.
Clot-busting drugs, also called thrombolytics, may be used in serious or life-threatening cases.
Doctors give these medicines through a vein to dissolve clots quickly, but they carry a higher risk of major bleeding, so they are not used in every case.
Invasive Techniques and Other Interventions
Some people need help beyond medicine. There are different options:
- Catheter-Based Clot Removal: Doctors use a thin tube called a catheter to reach the clot and remove it, especially if the pulmonary embolism (PE) is very large and dangerous.
- Inferior Vena Cava (IVC) Filter Placement: If a person cannot take blood thinners or they continue to form clots, doctors can put a filter in the bodyโs main veinโthe inferior vena cava. This filter blocks new clots from moving to the lungs. Some filters are temporary and can be removed later.
- Surgical Embolectomy: In rare cases, doctors may perform open surgery to remove a clot.
Doctors may also use oxygen therapy for breathing problems related to acute PE, along with hospital monitoring during severe cases.
Continuing Management and Monitoring
After the initial event, ongoing care helps prevent another pulmonary embolism or deep vein thrombosis (DVT).
Long-term anticoagulant medication is often needed. Providers may recommend compression stockings to help lower swelling or prevent clots in the legs.
Patients should attend regular follow-up visits, where doctors can check for side effects such as major bleeding and adjust treatment as needed.
If chronic thromboembolic pulmonary hypertension develops, doctors may offer more specialized treatment.
Getting Ready for Your Visit
Steps You Can Take Beforehand
Preparing a few things can help make your visit smoother:
Make a list of your symptoms. Write down when they started and how severe they are.
Gather your medical history. Note any recent surgeries, hospital stays, illnesses, or injuries that kept you inactive.
Keep travel details handy. Include information about any long-distance trips, especially if you sat still for many hours.
List all medicines and supplements. Include the name and dose of each item, even vitamins or herbal products.
Add family health history. Write down serious health issues found in close relatives.
Prepare questions. Jot down anything you want to ask during your appointment.
You might use a table to organize these details:
| Item | Details to Record |
|---|---|
| Symptoms | Onset, severity, type, triggers |
| Medicines | Name, dose, how often you take them |
| Recent Travel | Dates, locations, duration, activities |
What Your Provider Will Do
The doctor will examine your legs for signs of a clot, such as swelling and warmth.
They may check your heart and lungs. The doctor may also take your blood pressure and ask about your recent health and travels. After this first check, the doctor may order tests.
