Introduction:
l Disease spectrum from asymptomatic deep vein thrombosis to massive pulmonary embolism causing immediate death.
l About 79% of patients with pulmonary embolism have evidence of legs’ deep venous thrombosis.
l Pulmonary embolism occurs in up to 50% of patients with proximal deep venous thrombosis
l Pulmonary infarction is not usually present due to the dual circulation arising from the pulmonary and bronchial arteries.
Pathophysiology
l Anatomical obstruction cause compromised physiology
l Release of vasoactive and bronchoactive agents lead to deleterious ventilation–perfusion matching
l RV afterload increases, RV wall tension rises and lead to dilatation, dysfunction, and ischemia of the RV
l Death results from right ventricular failure
Risk factors-acquired
l Antiphospholipid antibody syndrome
l Oral contraceptives
l Hormone-replacement therapy
l Chemotherapy
l Obesity
l Central venous catheterization
l Immobilizer or cast
l Reduced mobility
l Advanced age
l Cancer
l Acute medical illness
l Major surgery
l Trauma
l Spinal cord injury
l Pregnancy and postpartum period
l Polycythemia vera
Risk factors - Hereditary
l Antithrombin deficiency
l Protein C deficiency
l Protein S deficiency
l Factor V Leiden
l Activated protein C resistance without factor V Leiden
l Prothrombin gene mutation
l Dysfibrinogenemia
l Plasminogen deficiency
Clinical manifestation
l Tachypnea and tachycardia-- Common but nonspecific
l Pleuritic chest pain and hemoptysis -- Frequent in pulmonary infarction ( smaller, more peripheral emboli, and may with pleural rub).
l Leg pain, warmth, or swelling-- Symptoms of DVT
l Elevated neck veins, a loud P2, a right-sided gallop, and right ventricular lift
l Pulmonary hypertension
l All signs and symptoms are neither sensitive nor specific.
l Clinical symptoms didn’t correlate with disease severity
l The possibility of massive pulmonary embolism should be considered in pts with sudden onset of near syncope or syncope, hypotension, extreme hypoxemia, electromechanical dissociation or cardiac arrest.
Image study 
l Ventilation–perfusion scanning
l Contrast-enhanced CT
l Magnetic resonance imaging (MRI)
l Standard pulmonary arteriography
l Imaging for detecting DVT
l Echocardiography
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