Pulmonary Embolism

Introduction

Pulmonary Embolism (PE) is a serious and potentially life-threatening medical condition that occurs when one or more arteries in the lungs become blocked by a blood clot. These clots usually form in the deep veins of the legs — a condition called Deep Vein Thrombosis (DVT) — and travel to the lungs through the bloodstream.

If not diagnosed and treated on time, pulmonary embolism can lead to severe complications, including lung damage, low oxygen levels, or even death. However, with early detection, effective treatment, and preventive care, the risk of serious outcomes can be significantly reduced.

What is Pulmonary Embolism?

Pulmonary embolism is a type of venous thromboembolism (VTE) — a group of conditions that involve blood clots forming in the veins. In PE, the clot (called an embolus) blocks blood flow to the lungs. This blockage prevents oxygen from reaching lung tissue and the rest of the body.

Depending on the size and location of the clot, pulmonary embolism can be mild, moderate, or severe. Large or multiple clots can cause a massive PE, which may lead to sudden death if not treated immediately.

Causes

The main cause of pulmonary embolism is a blood clot (thrombus) that travels from another part of the body, usually the legs or pelvis, into the lungs. However, other rare substances can also cause emboli, such as:

Fat embolism – from fractured bones.

Air embolism – from surgery or trauma.

Amniotic fluid embolism – during childbirth.

Tumor cells – in advanced cancers.

Common Risk Factors

People are more likely to develop PE if they have one or more of the following risk factors:

1. Deep Vein Thrombosis (DVT)

The most common source of pulmonary embolism.

2. Prolonged Immobility

Long flights, hospital stays, or bed rest.

3. Surgery or Trauma

Especially orthopedic or abdominal surgeries.

4. Cancer

Some cancers increase clotting tendencies.

5. Pregnancy and Postpartum Period

Hormonal changes and pressure on pelvic veins raise clot risks.

6. Birth Control Pills or Hormone Therapy

Estrogen increases clotting tendency.

7. Smoking

Damages blood vessel walls and promotes clot formation.

8. Obesity

Increases venous pressure and reduces circulation.

9. Heart Disease or Heart Failure

Poor blood flow promotes clot formation.

10. Genetic Clotting Disorders

Such as Factor V Leiden mutation or Prothrombin gene mutation.

Symptoms

The symptoms of PE can appear suddenly and vary depending on the size of the clot and how much of the lung is affected. Common symptoms include:

Major Symptoms:

• Sudden shortness of breath (dyspnea)
• Sharp chest pain (often worse when breathing deeply or coughing)
• Rapid heartbeat (tachycardia)
• Coughing up blood (hemoptysis)
• Lightheadedness or fainting
• Anxiety or feeling of doom

Other Associated Symptoms:

• Low oxygen levels (hypoxemia)
• Sweating and clammy skin
• Blue discoloration (cyanosis) of lips or nails
• Swelling and pain in one leg (DVT symptom)

⚠️ Note: In severe cases, pulmonary embolism can cause sudden collapse or cardiac arrest, requiring immediate emergency care.

Diagnosis

Diagnosing pulmonary embolism early is crucial. Since symptoms may mimic other conditions like heart attack, pneumonia, or anxiety disorders, proper diagnostic tests are essential.

1. Physical Examination

• The doctor checks:
• Heart rate and breathing rate
• Oxygen levels
• Leg swelling or tenderness (signs of DVT)

2. Blood Tests

• D-Dimer Test: Detects fragments of blood clots. A high level suggests clot formation.
• Arterial Blood Gas (ABG): Measures oxygen and carbon dioxide in blood.

3. Imaging Tests

• CT Pulmonary Angiography (CTPA): The most accurate test to detect PE and visualize the location of the clot.
• Ventilation-Perfusion (V/Q) Scan: Checks airflow and blood flow in lungs.
• Ultrasound of the Legs: Detects DVT.
• Chest X-ray: Helps rule out other conditions like pneumonia.

4. Electrocardiogram (ECG or EKG)

Helps identify heart strain or right heart stress caused by pulmonary embolism.

Treatment

The goal of treatment is to stop the clot from growing, prevent new clots, and restore normal blood flow to the lungs.

1. Anticoagulant Medications (Blood Thinners)

• These are the first-line treatment for most PE patients.
  Commonly used drugs include:
• Heparin (unfractionated or low molecular weight) – given via injection.
• Warfarin – oral anticoagulant for long-term use.
• Direct Oral Anticoagulants (DOACs) – such as rivaroxaban, apixaban, and dabigatran.
• Anticoagulants don’t dissolve existing clots but prevent new ones from forming while the body naturally breaks down the current clot.

2. Thrombolytic Therapy (Clot-Dissolving Drugs)

• Used in severe or life-threatening PE where immediate clot removal is needed.
• Common drugs: Alteplase (tPA), Streptokinase, Urokinase.
• ⚠️ High risk of bleeding; used only in critical cases.

3. Surgical or Catheter-Based Treatment

• Embolectomy: Surgical removal of the clot.
• Catheter-directed therapy: A thin tube delivers clot-dissolving drugs directly into the blocked artery.

4. Inferior Vena Cava (IVC) Filter

• If anticoagulants cannot be used (e.g., bleeding disorders), a filter is placed in the large vein (IVC) to catch clots before they reach the lungs.

5. Oxygen Therapy and Supportive Care

• Oxygen supply for breathing difficulty.
• IV fluids and medications to maintain blood pressure

Complications

If left untreated, pulmonary embolism can cause serious complications, such as:

1. Pulmonary Hypertension:
   High blood pressure in the lungs due to blockage or damage of pulmonary arteries.
2. Chronic Thromboembolic Pulmonary Hypertension (CTEPH):
   A rare long-term complication where clots don’t dissolve completely and lead to persistent high pressure in lung arteries.
3. Right Heart Failure:
   The right side of the heart works harder to pump blood through blocked lungs, leading to strain and failure.
4. Lung Tissue Damage (Pulmonary Infarction):
   Lack of oxygen can cause part of the lung tissue to die.
5. Death:
   A massive or untreated PE can be fatal within hours.

Prevention

Prevention is always better than cure. Pulmonary embolism can often be prevented with lifestyle changes and medical precautions, especially for high-risk individuals.

1. Stay Active and Avoid Prolonged Immobility

• Take breaks to walk or stretch every 1–2 hours during long journeys or office work.
• After surgery or illness, move your legs frequently or use compression devices.

2. Wear Compression Stockings

• These help maintain blood flow and reduce the risk of DVT, especially after surgery or during long flights.

3. Maintain a Healthy Weight

• Obesity increases the risk of clot formation, so a healthy diet and regular exercise are essential.

4. Quit Smoking

• Smoking damages blood vessels and increases clotting tendencies.

5. Use Blood Thinners When Prescribed

• For those with a history of DVT, PE, or heart disease, regular anticoagulant use (as prescribed) can prevent recurrence.

6. Stay Hydrated

• Dehydration thickens the blood, increasing clot risks. Drink plenty of fluids daily.

7. Monitor After Surgery or Hospitalization

• If you’re bedridden, ask your doctor about blood thinner injections or leg compression devices.

Living with Pulmonary Embolism

Living with PE means managing your health carefully to prevent recurrence. You can lead a normal life by following these guidelines:

Maintain a balanced diet (avoid excessive vitamin K if on warfarin).

Exercise regularly but safely.

Get regular INR blood tests if you take warfarin.

Avoid smoking and alcohol abuse.

Wear medical alert jewelry indicating your condition and medications.