Pulmonary embolism (PE) occurs when there is a disruption to the flow of blood in the pulmonary artery or its branches by a thrombus that originated somewhere else. In deep vein thrombosis (DVT), a thrombus develops within the deep veins, most commonly in the lower extremities. PE usually occurs when a part of this thrombus breaks off and enters the pulmonary circulation. Very rarely, PE can occur from the embolization of other materials into the pulmonary circulation such as air, fat, or tumor cells.Risk factors can be classified as genetic and acquired. Genetic risk factors include thrombophilia such as factor V Leiden mutation, prothrombin gene mutation, protein C deficiency, protein S deficiency, hyperhomocysteinemia, among others. Acquired risk factors include immobilization for prolonged periods (bed rest greater than three days, anyone traveling greater than 4 hours, whether by air, car, bus, or train), recent orthopedic surgery, malignancy, indwelling venous catheter, obesity, pregnancy, cigarette smoking, oral contraceptive pill use~Other predisposing factors for VTE include:~Fracture of lower limb Hospitalization for heart failure or atrial fibrillation/flutter within the previous three months Hip or knee replacement Major trauma History of previous venous thromboembolism Central venous lines Chemotherapy Congestive heart failure or respiratory failure Hormone replacement therapy Oral contraceptive therapy Postpartum period Infection (specifically pneumonia, urinary tract infection, and HIV) Cancer (highest risk in metastatic disease) Thrombophilia Bed rest greater than three days Obesity Pregnancy Cancer carries a high risk for thrombus formation and hence, PE. Pancreatic cancer, hematological malignancies, lung cancer, gastric cancer, and brain cancer carry the highest risk for VTThe most common symptoms of PE include the following: dyspnea, pleuritic chest pain, cough, hemoptysis, presyncope, or syncope. Dyspnea may be acute and severe in central PE, whereas it is often mild and transient in small peripheral PE. In patients with preexisting heart failure or pulmonary disease, worsening dyspnea may be the only symptom. Chest pain is a frequent symptom and is usually caused by pleural irritation due to distal emboli causing pulmonary infarction.
To evaluate the clinical characteristics, risk factors, management and outcome of patients admitted e acute pulmonary embolism in chest diseases department and Respiratory Icu in Assiut University hospital