trombosis

Trombosis is the formation of a blood clot, or thrombus, inside a blood vessel, which can obstruct flow and cause tissue damage. It can occur in arteries or veins and may lead to organ injury or failure if untreated.

Pathophysiology involves endothelial injury, stasis or abnormal flow, and hypercoagulability (Virchow's triad). Arterial thrombi are usually platelet-rich; venous thrombi are fibrin-rich and contain red cells.

Arterial thrombosis underlies myocardial infarction and ischemic stroke, while venous thrombosis includes deep vein thrombosis in the legs and cerebral venous sinus thrombosis; venous clots can migrate to the lungs as pulmonary embolism.

Risk factors include immobilization, surgery, cancer, pregnancy, hormonal therapy, genetic coagulation disorders, obesity, smoking.

Signs and symptoms vary by location. Deep vein thrombosis commonly causes leg swelling, warmth, and pain; pulmonary embolism may cause chest pain, shortness of breath; cerebral venous sinus thrombosis can present with headache and neurologic deficits.

Diagnosis relies on imaging and laboratory testing. D-dimer testing helps exclude thrombosis in low-risk patients; ultrasound is used for DVT; CT pulmonary angiography for PE; MRI for cerebral venous sinus thrombosis.

Treatment consists of anticoagulation with heparin or low-molecular-weight heparin followed by long-term warfarin or direct oral anticoagulants; thrombolysis or mechanical thrombectomy may be used in severe cases; address provoking factors.

Prevention includes early mobilization after surgery, routine prophylaxis in high-risk patients, and management of underlying conditions; prognosis depends on location, extent, and comorbidity; pulmonary embolism and cerebral venous thrombosis carry higher risk.