Pulmonary embolism (PE) is a serious medical condition that occurs when a blood clot blocks a blood vessel in the lungs. This blockage can prevent blood from reaching parts of the lung, leading to reduced oxygen levels in the body. PE often arises from deep vein thrombosis (DVT), where clots form in the deep veins of the legs and travel to the lungs. Symptoms of PE may include sudden shortness of breath, chest pain, and coughing up blood. Risk factors for developing PE include prolonged immobility, certain medical conditions, and lifestyle factors such as smoking. Early diagnosis and treatment are crucial for improving outcomes.