PULMONARY EMBOLISM

A pulmonary embolism is a sudden blockage in a lung artery. The cause is usually a blood clot in the leg called a deep vein thrombosis that breaks loose and travels through the bloodstream to the lung. Pulmonary embolism is a serious condition that can cause permanent damage to the affected lung,low oxygen levels in your blood and  damage to other organs in your body from not getting enough oxygen.If a clot is large, or if there are many clots, pulmonary embolism can cause death.

Causes

Blood clots can form for a variety of reasons. Pulmonary embolisms are most often caused by deep vein thrombosis, a condition in which blood clots form in veins deep in the body. The blood clots that most often cause pulmonary embolisms typically begin in the legs or arms.

Factors that increase a person’s risks of deep vein thrombosis and pulmonary embolism include:

• cancer
• a close family member with a history of embolisms
• fractures of the leg or hip
• genetic blood clotting disorders (hypercoagulable states), including Factor V Leiden, prothrombin gene mutation, and elevated levels of homocysteine
• a history of heart attack or stroke
• major surgery
• obesity
• a sedentary lifestyle

Symptoms

Pulmonary embolism symptoms can vary greatly, depending on how much of your lung is involved, the size of the clots (almost never single) and your overall health — especially the presence or absence of underlying lung disease or heart disease.

Common signs and symptoms include:

• Shortness of breath. This symptom typically appears suddenly and always gets worse with exertion.
• Chest pain. You may feel like you're having a heart attack. The pain may become worse when you breathe deeply (pleurisy), cough, eat, bend or stoop. The pain will get worse with exertion but won't go away when you rest.
• Cough. The cough may produce bloody or blood-streaked sputum.

Other signs and symptoms that can occur with pulmonary embolism include:

• Leg pain or swelling, or both, usually in the calf
• Clammy or discolored skin (cyanosis)
• Excessive sweating
• Rapid or irregular heartbeat
• Lightheadedness or dizziness

Diagnosis

A detailed history of the patient is taken which includes general health, medical history and symptoms with a physical exam.To confirm the diagnosis of pulmonary embolism, the physician may order specific tests, which may include some of the following:

• Chest x-ray
• Electrocardiography (ECG) which measures your heart’s electrical activity
• D-dimer enzyme-linked immunosorbent assay, a blood test that shows an increase of a type of protein that may rise after a pulmonary embolism
• Lung scanning, which measures blood flow in your lungs and your air intake
• Spiral computed tomography (CT) scan
• Pulmonary angiography, which shows x ray pictures of the blood vessels in your lungs
• Duplex ultrasound, which allows your physician to measure the speed of blood flow and to see the structure of your leg veins
• Venography, which shows x-ray pictures of your leg veins

Treatment

Treatment options for pulmonary embolism include:

• Anticoagulants. Also described as blood thinners, these medications decrease the ability of the blood to clot. Examples of anticoagulants include warfarin (Coumadin) and heparin.
• Fibrinolytic therapy. Also called clot busters, these medications are given intravenously (IV) to break down the clot.
• Vena cava filter. A small metal device placed in the vena cava (the large blood vessel that returns blood from the body to the heart) may be used to prevent clots from traveling to the lung. These filters are generally used in patients who cannot receive anticoagulation treatment (for medical reasons), who develop additional clots even with anticoagulation treatment, or who develop bleeding complications from anticoagulation.
• Pulmonary embolectomy. Surgical removal of a pulmonary embolism. This procedure is generally performed only in severe situations in which the PE is very large, the patient either cannot receive anticoagulation and/or thrombolytic therapy due to other medical considerations or has not responded adequately to those treatments, and the patient's condition is unstable.
• Percutaneous thrombectomy. Insertion of a catheter (long, thin, hollow tube) to the site of the embolism, using X-ray guidance. Once the catheter is in place, the catheter is used to break up the embolism, extract it (pull it out), or dissolve it by injecting thrombolytic medication.

Prevention

The most effective way to prevent pulmonary embolism is to prevent DVTs from forming or starting to move in the blood vessels. If you have DVT, you may be prescribed an anticoagulant. Anticoagulants can also be given to people with DVT to prevent the condition. They can also protect against stroke.

Non-medication methods to help prevent DVT include using compression devices and compression stockings (to ensure blood doesn't pool in the legs), and frequently stretching, massaging, and moving your lower leg muscles if you are inactive for a long time. You can also reduce your risk factors for getting blood clots, for instance by quitting smoking and controlling your blood pressure.

Points to remember

• Pulmonary embolism usually is caused by a thrombus in the proximal deep veins of the leg that breaks off and lodges in the lung
• Patients may be asymptomatic or may present with typical symptoms, including dyspnea and chest pain. Patients with massive pulmonary embolism may present with hypotension, shock, or sudden death
• An integrated diagnostic approach involving clinical prediction rules and noninvasive testing can be used to evaluate patients in whom pulmonary embolism is suspected. Clinical prediction rules stratify patients into low, moderate, or high pretest probability of pulmonary embolism categories, which, in turn, helps to determine the need for further diagnostic testing
• The aggressiveness of treatment is dependent on the severity of pulmonary embolism. Treatment of nonmassive pulmonary embolism involves rapid initiation of anticoagulant therapy. Thrombolysis is indicated in patients who are hemodynamically unstable (massive pulmonary embolism). Surgical or angiographic embolectomy only should be done in experienced institutions
• Prevention of deep vein thrombosis (DVT) in hospitalized patients is crucial to preventing pulmonary embolism