Acute pulmonary embolism

Q: Which is the third most common cause of cardiovascular death? show answer

A: Venous thromboembolism (VTE) and pulmonary embolism (PE) is the third most common cause of cardiovascular death after myocardial infarction and cerebrovascular accidents.

Q: How is the pathophysiology of pulmonary embolism? show answer

A: Pulmonary embolism occurs when deep venous thrombi detach and embolize to the pulmonary circulation, promoting vascular occlusion and impairing gas exchange and circulation, contributing to ventilation-perfusion mismatch. Besides, humoral mediators such as serotonin and thromboxane are released from activated platelets and may trigger vasoconstriction in the lung's unaffected area.

Q: Which are the most frequent symptoms of acute pulmonary embolism? show answer

A: The most common acute pulmonary embolism symptoms are dyspnea, chest pain, and cough.

Q: Which are the most common signs of acute pulmonary embolism? show answer

A: Fever, tachycardia, tachypnea, and peripheral vascular collapse are the most common acute pulmonary embolism signs. Cyanosis, hemoptysis, syncope, and the various manifestations of acute cor pulmonale may less commonly occur.

Q: Which are the clinical conditions that may simulate acute pulmonary thromboembolism? show answer

A: The clinical conditions that have symptoms similar to those of acute pulmonary thromboembolism include pericarditis, acute myocardial infarction, aortic dissection, esophagitis, esophageal rupture, pneumonia, lung cancer, pneumothorax, pleuritis, rib fractures, and metastatic deposits

Q: Which are the imaging modalities available in the evaluation of acute pulmonary embolism? show answer

A: The imaging modalities available in the evaluation of acute pulmonary embolism include chest radiographs, computed tomography pulmonary angiography (CTPA), CT venography (CTV), magnetic resonance pulmonary angiography (MRPA), nuclear medicine ventilation/perfusion, venous ultrasound, echocardiography, and catheter pulmonary angiography.

Q: Is the chest radiography useful in the diagnosis of pulmonary embolism? show answer

A: The chest radiography is not useful in diagnosing pulmonary embolism, per se, but it is useful in excluding other causes of acute chest pain such as pneumonia, pneumothorax, or pulmonary edema.

Q: In a patient with suspected acute pulmonary embolism and contraindications to CT angiography, what is the significance of deep venous thrombosis (DVT)? show answer

A: In a patient with suspected acute pulmonary embolism, in whom there are contraindications for CT angiography, the DVT diagnosis by ultrasonography is sufficient to rule pulmonary embolism.

Q: What is the importance of CT pulmonary angiography (CTPA) in pulmonary thromboembolism? show answer

A: CTPA is the imaging modality of choice for diagnosing pulmonary embolism because it is rapid, permits direct visualization of pulmonary emboli, and can demonstrate other potential causes of the patient`s symptoms. The sensitivity and specificity of CT angiography to detect pulmonary embolism approach 100%.

Q: Which lobes of the lungs are more frequently affected in pulmonary embolism? show answer

A: In the lungs, the lower lobes are more frequently affected than the upper, with bilateral lung involvement common. Larger emboli wedge in the main pulmonary artery, while smaller emboli occlude the peripheral arteries. Peripheral pulmonary embolism can lead to pulmonary infarction, manifested by intra-alveolar hemorrhage. Pulmonary infarction occurs in about 10% -15% of patients without underlying cardiopulmonary disease.