thromboemboli

Thromboembolus refers to a blood clot that forms in one location and travels through the bloodstream to lodge in a distant vessel, causing an occlusion. When the embolus is a dislodged thrombus, the term thromboembolus is often used. Embolism can be arterial or venous; arterial emboli commonly cause stroke or myocardial infarction, while venous thromboembolism most often results in pulmonary embolism following deep vein thrombosis.

Pathophysiology involves Virchow’s triad: blood stasis, hypercoagulability, and endothelial injury. Additional risk factors include immobilization, surgery, cancer, pregnancy, hormone therapy, obesity, cardiovascular disease, and inherited or acquired clotting disorders. The tendency to form and propagate clots varies with comorbidity and circumstance.

Venous thromboembolism encompasses deep vein thrombosis and pulmonary embolism. Deep veins in the legs or pelvis are frequent sources; fragments may travel to the lungs and cause PE. Arterial thromboembolism often arises from the heart or arterial beds with atherothrombosis or arrhythmias, leading to acute ischemic events in the brain, heart, or limbs.

Clinical presentation depends on the affected organ. DVT may cause leg swelling and pain; PE can cause sudden shortness of breath, chest pain, and tachycardia. Diagnostic workup includes compression ultrasound for DVT, and CT pulmonary angiography for PE; D-dimer testing is non-specific and used in risk assessment. Cardiac or cerebral emboli may be evaluated with appropriate imaging.

Treatment centers on anticoagulation to prevent further clotting, typically with heparin followed by a direct oral anticoagulant or warfarin. Thrombolysis or surgical or catheter-directed embolectomy may be indicated in massive or life-threatening PE or large arterial emboli. Prevention focuses on risk factor modification and prophylactic anticoagulation in high-risk settings.