Final answer:
A pulmonary embolism can be a direct result of thrombophlebitis, which is the presence of blood clots in the veins that can break free and block the pulmonary arteries.
Step-by-step explanation:
A pulmonary embolism can be a direct result from a condition known as thrombophlebitis. Thrombophlebitis is when thrombi (blood clots) form within the veins, typically due to inflammation. These clots can break off and become an embolus that travels through the bloodstream. If this embolus lodges in a pulmonary artery, it can block the blood flow to the lungs, causing a pulmonary embolism. This is a medical emergency and can lead to severe consequences, including lung damage and potential death. Conditions such as varicose veins can contribute to the development of thrombophlebitis by causing blood to pool and increasing the risk of clot formation within the veins.