Pulmonary Embolism

Pulmonary Embolism
The occlusion of one or more pulmonary arteries by thrombi that originate elsewhere, typically in the large veins of the legs or pelvis.
Etiology
Nearly all pulmonary emboli arise from thrombi in the veins of the legs or pelvis (deep venous thrombosis) with the Risk of embolization is higher with thrombi proximal to the calf veins, also the thromboemboli can also originate in arm veins or central veins of the chest (caused by central venous catheters or resulting from thoracic outlet syndromes).
Risk factors :
• Conditions that impair venous return, including bed rest and immobility
• Conditions that cause endothelial injury or dysfunction
• Underlying hypercoagulable (thrombophilic) disorders
age > 60 yr
Cancer
Hormonal modulation
• Estrogen receptor modulators (eg, raloxifene, tamoxifen)
• Exogenous estrogens and progestins, including oral contraceptives and estrogen
• Exogenous testosterone
Medical dis. As: Heart failure ,Myeloproliferative disorders (hyperviscosity),
Nephrotic syndrome , Sickle cell disease & stroke
Immobilization
Indwelling venous catheters
Obesity
Pregnancy/postpartum period
Prior thromboembolism
Smoking