Emergency & Acute Care

Pulmonary Embolism — Clinical Reference

Last reviewed 2026-06-16 · TruelyserMD Clinical Reference
For Patients & General Readers

Pulmonary embolism (PE) is a serious condition where a blood clot, usually from the legs, travels to the lungs and blocks blood flow. It can happen to anyone, but is more common in people who are immobile, have had surgery, or have certain medical conditions. Prompt diagnosis and treatment are crucial to prevent serious complications or death.

Clinical Overview

Pulmonary embolism (PE) is a potentially fatal condition caused by obstruction of the pulmonary vasculature by an embolus, most commonly a thrombus originating from deep vein thrombosis (DVT). It leads to impaired gas exchange, hemodynamic compromise, and can result in right ventricular strain or failure.

Clinical Presentation

Signs & Symptoms

Symptoms (Patient-Reported)

  • Sudden shortness of breath
  • Sharp chest pain that worsens with breathing
  • Cough, sometimes with bloody mucus
  • Rapid heartbeat
  • Feeling dizzy or lightheaded
  • Sweating
  • Anxiety

Signs (Clinician-Observed)

  • Tachypnea (>20 breaths/min)
  • Tachycardia (>100 beats/min)
  • Hypoxemia (SpO2 < 90% on room air)
  • Crackles on lung auscultation
  • Jugular venous distension
  • Low blood pressure (hypotension)

Differential Diagnoses

ConditionDistinguishing Feature
PneumoniaOften associated with fever, productive cough, and focal consolidation on chest X-ray, whereas PE typically presents with pleuritic pain and hypoxemia without clear infiltrates.
PneumothoraxCharacterized by sudden onset dyspnea and pleuritic chest pain, but often with decreased breath sounds on the affected side and a visible pleural line on imaging.
Acute Coronary Syndrome (ACS)Chest pain can be similar, but ACS is typically associated with exertional angina, ST-segment changes on ECG, and elevated cardiac biomarkers, rather than pleuritic pain and hypoxemia.
PericarditisChest pain is often positional and relieved by sitting up, and ECG may show diffuse ST elevation and PR depression, unlike the segmental changes seen in PE.
Pulmonary HypertensionWhile PE can cause pulmonary hypertension, primary pulmonary hypertension is a chronic condition with progressive dyspnea and right heart failure symptoms, often without acute exacerbations of pleuritic pain or hemoptysis.
Aortic DissectionCharacterized by sudden, severe, tearing chest or back pain and often associated with neurological deficits or pulse deficits, distinct from the pleuritic pain of PE.

Red Flags — Seek Immediate Care

Key Investigations

Management Overview

Management focuses on anticoagulation to prevent further clot formation and allow the body to lyse existing clots, with consideration for thrombolysis or embolectomy in hemodynamically unstable patients. Risk stratification is crucial to guide treatment intensity and duration.

Disclaimer: This article is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. TruelyserMD does not replace clinical judgement.