Pulmonary embolism

Introduction

Pulmonary embolism is the sudden obstruction of one or more pulmonary arteries by a blood clot (thrombus), most commonly originating from a deep vein in the lower limbs. It is a potentially life-threatening cardiovascular emergency, affecting approximately 1 in 1,000 people each year. It represents the third leading cause of cardiovascular death after myocardial infarction and stroke. Rapid management is essential: mortality drops from 30% in the absence of treatment to less than 5% when diagnosed and treated in time.

If you experience sudden dyspnea, unexplained chest pain, or faintness, contact your primary care physician first. If they are unavailable, Docadom offers an emergency consultation by a doctor at home: call 021 845 45 45 or use our application available on the App Store and Google Play. In case of signs suggestive of a pulmonary embolism (sudden chest pain, severe shortness of breath, syncope), call 144 immediately.

Who is at risk?

The main risk factors are: personal or family history of venous thrombosis, prolonged immobilization (surgery, cast, bed rest, long travel), active cancer, estrogen-progestogen contraception, pregnancy and postpartum, hereditary thrombophilias (Factor V Leiden, prothrombin gene mutation, antithrombin deficiency), hormone replacement therapy, advanced age, obesity, smoking, heart failure, chronic inflammatory diseases, nephrotic syndrome. COVID-19 and certain severe infections also increase the risk of thrombosis.

Symptoms of Pulmonary Embolism

Symptoms are highly variable, ranging from asymptomatic forms to cardiac arrest. It is one of the most difficult diagnoses because no single sign is specific.

Key Symptoms

• Dyspnea: shortness of breath, often of sudden onset, at rest or with minimal effort. This is the most common symptom.

• Chest pain: pleuritic, worse with deep inspiration, often localized to one side.

• Tachycardia: heart rate > 100 bpm, sometimes associated with palpitations.

• Dry cough, sometimes accompanied by hemoptysis (coughing up blood).

• Syncope or fainting, especially in massive forms.

• Anxiety, a feeling of impending doom.

• Sweating, paleness, cyanosis in severe cases.

• Signs of deep vein thrombosis: calf pain, asymmetric leg swelling, redness, warmth.

• low blood pressure, or even shock in massive forms.

When to seek emergency care?

Any suspicion of a pulmonary embolism is a life-threatening emergency that requires an immediate call to 144:

• Sudden onset of dyspnea or unexplained chest pain.

• Presence of risk factors (recent surgery, immobilization, cancer, long travel, cast).

• Signs of deep vein thrombosis in a leg.

• Occurrence of syncope or fainting.

• Signs of severity: low blood pressure, shock, cyanosis, marked tachycardia.

• Pregnant or postpartum women experiencing these symptoms.

What to do before calling Docadom? Pulmonary embolism is one of the rare situations where you must go directly through 144 without waiting. Still, contact your primary care physician in parallel if they are reachable, or Docadom at 021 845 45 45 or via our smartphone app (App Store and Google Play) for situations where suspicion is low and tolerance is good. In case of sudden dyspnea, syncope, or intense chest pain with a history of thromboembolism, dial 144 without delay.

Causes and Pathophysiology

Pulmonary embolism is most often the consequence of a deep vein thrombosis (DVT) of the lower limbs or pelvis. A blood clot forms in a vein, detaches, and travels through the venous circulation to the pulmonary arteries.

Virchow's Triad

Three mechanisms promote the formation of a thrombus:

• Venous stasis: slowing of blood flow (immobilization, bed rest, heart failure).

• Hypercoagulability: cancer, pregnancy, contraception, thrombophilia, inflammation.

• Venous wall injury: surgery, trauma, venous catheter.

Transient and Persistent Factors

Transient factors: surgery (especially orthopedic), trauma, immobilization, prolonged travel (> 6 h), pregnancy, postpartum, estrogen-progestogen contraception. Persistent factors: cancer, thrombophilia, chronic inflammatory disease, heart failure, history of thromboembolism, age > 70 years, obesity.

Diagnosis of Pulmonary Embolism

Diagnosis is difficult because the symptoms are non-specific. It relies on a structured approach combining clinical probability, blood tests, and imaging.

Diagnostic Methods

• Assessment of clinical probability: Wells or revised Geneva scores.

• D-dimer test: a normal value rules out the diagnosis in case of low clinical probability. A high value requires imaging.

• CT pulmonary angiogram: the gold standard exam, which directly visualizes clots in the pulmonary arteries.

• Ventilation/perfusion lung scan: alternative when CT is contraindicated (pregnancy, kidney failure, iodine allergy).

• Venous ultrasound of the lower limbs: looks for an associated deep vein thrombosis.

• Echocardiography: assesses the impact on the right ventricle in severe cases.

• Electrocardiogram (ECG): sinus tachycardia, S1Q3T3 pattern, right bundle branch block.

• Arterial blood gas test: hypoxemia, hypocapnia.

• Lab panel: CBC, electrolytes, creatinine, troponin, BNP/NT-proBNP, coagulation profile.

Alternative Diagnoses

Several pathologies can mimic a pulmonary embolism:

• Myocardial infarction, unstable angina.

• Pneumonia, pleurisy, pneumothorax.

• Aortic dissection.

• Heart failure, pulmonary edema.

• Asthma attack or exacerbation of chronic bronchitis.

• Panic disorder with hyperventilation.

• Pericardial tamponade, myocarditis.

Treatment of Pulmonary Embolism

Treatment aims to prevent the clot from growing, prevent recurrences, treat hemodynamic instability, and avoid post-thrombotic syndrome.

Anticoagulation

Anticoagulation is the cornerstone of treatment:

• Initial phase: low molecular weight heparin (enoxaparin, tinzaparin), fondaparinux, or directly a direct oral anticoagulant (DOAC) depending on the situation.

• Maintenance phase: DOAC (apixaban, rivaroxaban, dabigatran, edoxaban) or VKA (warfarin, acenocoumarol) with a target INR between 2 and 3.

• Duration: at least 3 months, prolonged or lifelong in case of persistent risk factors, cancer, or recurrence.

• For pregnant women: low molecular weight heparins only (DOACs and VKAs are contraindicated).

Treatment of Severe Forms

• Thrombolysis: alteplase intravenous infusion, indicated in high-risk pulmonary embolisms with shock or hypotension.

• Thrombectomy endovascular or surgical, in case of contraindication or failure of thrombolysis.

• Vena cava filter in the inferior vena cava, in case of contraindication to anticoagulation.

• Intensive care: fluid resuscitation, norepinephrine, dobutamine, oxygen therapy, or ECMO in case of cardiac arrest.

Associated Measures

Early ambulation under effective anticoagulation. Compression stockings in certain cases. Screening for cancer in patients without an obvious risk factor. Thrombophilia screening in specific situations (recurrences, family history, young age). Patient education: warning signs, drug interactions.

Prevention of Pulmonary Embolism

Prevention relies on identifying high-risk situations and the appropriate use of preventive anticoagulants.

• Early ambulation after surgery or childbirth.

• Preventive anticoagulation with LMWH during major orthopedic, abdominal, or oncological surgeries, or during prolonged bed rest.

• Compression stockings in patients at moderate risk, during long travels.

• Adequate hydration, especially during long trips.

• Leg movement during long journeys (flexing, walking).

• Smoking cessation, maintaining a healthy weight, regular physical activity.

• Benefit/risk assessment of hormone therapy (contraception, HRT).

• Close medical follow-up for patients with a history of thromboembolism.

Potential Complications

Pulmonary embolism can lead to serious immediate or long-term complications.

Acute Complications

• Cardiogenic shock and cardiopulmonary arrest in massive forms.

• Acute right ventricular failure.

• Pulmonary infarction: tissue death of a part of the lung parenchyma.

• Bleeding associated with anticoagulant treatment.

Chronic Complications

• Recurrence of pulmonary embolism or deep vein thrombosis.

• Post-thrombotic syndrome of the lower limbs: pain, swelling, ulcers.

• Chronic thromboembolic pulmonary hypertension: a rare but serious complication.

• Psychological impact: anxiety, fear of recurrence.

When to Contact a Doctor for Suspected Pulmonary Embolism

Pulmonary embolism is an absolute emergency that requires rapid action:

• As a first resort, if the situation is not critical: contact your primary care physician, who can assess clinical probability and direct you quickly.

• If your primary care physician is unavailable and symptoms are moderate (progressive shortness of breath, moderate pleuritic chest pain), Docadom offers an emergency home visit by a physician. Call 021 845 45 45 or request a visit via our mobile app, available for free on the App Store and Google Play.

• In case of signs of severity (sudden dyspnea, syncope, severe chest pain, signs of shock), immediately call 144. Massive pulmonary embolism can only be treated in a hospital environment.

Conclusion: Keep Diagnosis High on the List

Pulmonary embolism is a common vascular emergency whose diagnosis is challenging due to the variability of symptoms. It results from the migration of a venous clot to the pulmonary arteries, often in the context of identifiable risk factors. It is characterized by dyspnea, chest pain, tachycardia, and sometimes syncope, which can lead to extremely serious complications such as cardiogenic shock, right ventricular failure, or chronic pulmonary hypertension.

At the slightest doubt, consult your primary care physician first. If they are not available and the situation is not critical, Docadom provides you with an emergency doctor at home 7 days a week: call 021 845 45 45 or use our mobile app (App Store, Google Play) to request an urgent consultation. If there is a suspicion of pulmonary embolism with signs of severity, do not hesitate: call 144.