Pulmonary embolism
Pulmonary embolism (PE) occurs when a thrombus, usually originating from a deep vein thrombosis in the lower extremities, travels through the venous system and lodges in the pulmonary artery. This blockage disrupts blood flow, causing ventilation–perfusion mismatch, increased dead space, and right ventricular strain. Risk factors follow Virchow’s triad: stasis, hypercoagulability, and endothelial injury. Common symptoms include acute dyspnea, pleuritic chest pain, tachycardia, and hemoptysis. Diagnosis relies on D-dimer testing and CT pulmonary angiography. Treatment includes anticoagulation, thrombolysis, or invasive intervention.































































































