Tromboembolus

Tromboembolus, also spelled thromboembolus, is a detached intravascular thrombus that travels through the circulation and may occlude a downstream vessel. It represents a clot that formed at one site and became carried to a distant point, where it can block blood flow.

Most thromboemboli originate from deep vein thrombosis in the legs or pelvis and travel to the lungs, causing pulmonary embolism. Left-sided thrombi, formed in the atria or ventricles, can cause systemic embolism to organs such as the brain, kidneys, spleen, or intestines. Common risk factors include immobilization, cancer, recent surgery, obesity, estrogen therapy, prior thromboembolism, atrial fibrillation, and inherited thrombophilias.

Clinical presentation depends on the location and size of the occlusion. Pulmonary embolism commonly causes sudden shortness of breath, chest pain, tachycardia, and sometimes syncope or hypotension in massive cases. Systemic embolism may present with neurologic deficits in stroke, abdominal symptoms from organ infarction, or other focal signs.

Diagnosis relies on clinical suspicion supported by testing. D-dimer testing is sensitive but nonspecific. Imaging includes CT pulmonary angiography for suspected pulmonary embolism and ultrasound to detect concomitant deep vein thrombosis. Echocardiography may reveal right heart strain in severe cases.

Treatment focuses on anticoagulation as first-line therapy, typically starting with heparin and transitioning to a direct oral anticoagulant or vitamin K antagonist. Massive pulmonary embolism may require thrombolysis or surgical/catheter embolectomy. In cases where anticoagulation is contraindicated, mechanical filters or alternative strategies may be considered. Prevention centers on risk factor modification and appropriate anticoagulation for high-risk patients. Prognosis varies with embolus size, location, and underlying health; early recognition improves outcomes.