émbolos

An embolus is a discrete intravascular particle that travels through the bloodstream from its point of origin until it lodges in a vessel, potentially causing an occlusion. The process of obstruction caused by an embolus is called an embolism. An embolus may be composed of a wide range of materials, including blood clots, fat, air, tumor fragments, bacteria, or amniotic fluid.

Common types of emboli include thromboemboli (the most frequent type, arising from dislodged clots), fat emboli (from broken bones or trauma to fatty tissue), air emboli (air bubbles entering the circulation, sometimes during procedures or diving), septic emboli (infected material spreading through the blood), tumor emboli (cancer cells traveling in the bloodstream), and amniotic fluid emboli (a rare obstetric emergency). The clinical impact of an embolus depends largely on its size, composition, and the location where it becomes lodged. A pulmonary embolism typically results from venous thromboembolism, whereas arterial emboli can cause strokes, limb ischemia, or organ infarction.

Diagnosis relies on clinical suspicion supported by imaging and laboratory testing. Suspected pulmonary embolism is evaluated with CT pulmonary angiography, and deep vein thrombosis may be diagnosed with ultrasound. Other sites of embolic occlusion are identified via appropriate imaging (e.g., MRI or CT for brain or organ infarcts). D-dimer testing can aid in ruling out thrombosis in low-risk patients but is not specific.

Treatment is etiologically dependent and may include anticoagulation, thrombolysis for life-threatening embolism, and surgical or endovascular removal of the embolus in selected cases. Supportive care, oxygen therapy, and treatment of the underlying cause are also important. Prevention focuses on risk factor modification and appropriate prophylaxis in high-risk settings, such as after surgery or during prolonged immobilization.