Pulmonary Embolism

Pulmonary embolism is blockage of the pulmonary artery by a blood clot, fat, air or clumped tumor cells. By far the most common form of pulmonary embolism is a thromboembolism, which occurs when a blood clot, generally a venous thrombus, becomes dislodged from its site of formation and embolizes to the arterial blood supply of one of the lungs.

Symptoms may include difficulty breathing, pain during breathing, and more rarely circulatory instability and death. Treatment, usually, is with anticoagulant medication, such as warfarin. Other rarer forms of pulmonary embolism occur when material other than a blood clot is responsible. Such materials can include fat or bone, air, and amniotic fluid.

Acutely, supportive treatments, such as oxygen or analgesia, are often required. Massive PE causing hemodynamic instability is an indication for thrombolysis, the enzymatic destruction of the clot with medication. Some advocate its use also if right ventricular dysfunction can be demonstrated on echocardiography.

In most cases, anticoagulant therapy is the mainstay of treatment. Heparin, low molecular weight heparins, or fondaparinux is administered initially, while warfarin therapy is commenced. Warfarin therapy is usually continued for 3-6 months, or "lifelong" if there have been previous DVTs or PEs, or none of the usual risk factors is present. Warfarin therapy often requires frequent dose adjustment and monitoring of the INR. In PE, INRs between 2.0 and 3.0 are generally considered ideal. If another episode of PE occurs under warfarin treatment, the INR window may be increased to e.g. 2.5-3.5 or anticoagulation may be changed to a different anticoagulant e.g. low molecular weight heparin. In patients with an underlying malignancy, therapy with a course of low molecular weight heparin may be favored over warfarin based on the results of the CLOT trial. Similarly, pregnant women are often maintained on low molecular weight heparin to avoid the known teratogenic effects of warfarin. If anticoagulant therapy is contraindicated and/or ineffective an inferior vena cava filter may be implanted.

...More at Wikipedia 

Related Links:

• US National Library of Medicine
• Mayo Clinic

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