thrombos

Thrombus (plural thrombi or thrombos) is a blood clot that forms within a blood vessel or heart chamber during life. It develops from a mesh of platelets, fibrin, and blood cells attached to abnormal endothelium and can obstruct flow or detach to become an embolus, traveling to distant sites. Thrombi can form in arteries or veins.

Pathophysiology and types: Thrombosis is influenced by Virchow's triad—stasis of flow, endothelial injury, and hypercoagulability. Arterial thrombi are often platelet-rich and form at sites of atherosclerotic plaque rupture, whereas venous thrombi tend to be fibrin- and red cell-rich and form with slow flow and hypercoagulable states.

Clinical relevance: Arterial thrombi commonly cause myocardial infarction or ischemic stroke, while venous thrombi cause deep vein thrombosis in the legs and can lead to pulmonary embolism if a portion breaks loose.

Diagnosis: When thrombosis is suspected, clinicians use blood tests such as D-dimer and imaging. Duplex ultrasonography detects DVT; CT pulmonary angiography or V/Q imaging identifies PE; arterial occlusions may be diagnosed with CT or MR angiography and relevant clinical tests.

Treatment and prevention: Anticoagulation is the mainstay of therapy, with options including heparin followed by a vitamin K antagonist or direct oral anticoagulants. Thrombolysis and mechanical thrombectomy may be used for life-threatening occlusions. Preventive measures focus on risk factor modification, early mobilization, and, when needed, long-term anticoagulation to prevent recurrence.