Why is it sometimes impossible to find a cause for a pulmonary embolism? | Causes of a pulmonary embolism

Why is it sometimes impossible to find a cause for a pulmonary embolism? The cause of a pulmonary embolism is not always an obvious thrombosis, i.e. the occlusion of a vein in a leg by a blood clot. Embolisms can also be triggered by amniotic fluid at birth. An air embolism can also be the … Why is it sometimes impossible to find a cause for a pulmonary embolism? | Causes of a pulmonary embolism