Pulmonary Embolism: Difference between revisions

'''Pulmonary embolism''' ('''PE''') is a blockage of the [[pulmonary artery|main artery of the lung]] or one of its branches by a substance that has travelled from elsewhere in the body through the bloodstream ([[embolism]]). Usually this is due to embolism of a [[thrombus]] (blood clot) from the [[deep vein thrombosis|deep veins in the legs]], a process termed [[venous thromboembolism]]. A small proportion is due to the embolization of [[air embolism|air]], [[fat embolism|fat]], talc in drugs of intravenous drug abusers or [[amniotic fluid embolism|amniotic fluid]]. The obstruction of the blood flow through the [[lung]]s and the resultant pressure on the [[right ventricle]] of the heart leads to the symptoms and signs of PE. The risk of PE is increased in various situations, such as [[cancer]] or prolonged [[bed rest]].<cite>Goldhaber></cite>

Symptoms of pulmonary embolism include [[dyspnea|difficulty breathing]], [[pleuritic chest pain|chest pain on inspiration]], and [[palpitation]]s. [[Clinical sign]]s include low blood [[oxygen saturation]] and [[cyanosis]], [[tachypnea|rapid breathing]], and [[tachycardia|a rapid heart rate]]. Severe cases of PE can lead to [[Collapse (medical)|collapse]], [[shock (circulatory)|abnormally low blood pressure]], and [[cardiac arrest|sudden death]].<ref name=Goldhaber/>

Diagnosis is based on these clinical findings in combination with laboratory tests (such as the [[D-dimer]] test) and imaging studies, usually [[CT pulmonary angiography]]. Treatment is typically with [[anticoagulant]] medication, including [[heparin]] and [[warfarin]]. Severe cases may require [[thrombolysis]] with drugs such as [[tissue plasminogen activator]] (tPA) or may require surgical intervention via [[pulmonary thrombectomy]].<ref name=Goldhaber/>

Symptoms of PE are sudden-onset [[dyspnea]] (shortness of breath), [[tachypnea]] (rapid breathing), [[chest pain]] of a "pleuritic" nature (worsened by breathing), [[cough]] and [[hemoptysis]] (coughing up blood). More severe cases can include signs such as [[cyanosis]] (blue discoloration, usually of the lips and fingers), [[Collapse (medical)|collapse]], and [[shock (circulatory)|circulatory instability]] due to decreased blood flow through the lungs and into the left side of the heart. About 15% of all cases of [[Sudden cardiac death|sudden death]] are attributable to PE.<ref name=Goldhaber/>

On physical examination, the lungs are usually normal. Occasionally, a [[pleural friction rub]] may be audible over the affected area of the lung (mostly in PE with infarct) . A [[pleural effusion]] is sometimes present that is transudative, detectable by decreased percussion note, audible breath sounds and vocal resonance. Strain on the right ventricle may be detected as a left parasternal heave, a loud [[heart sounds|pulmonary component of the second heart sound]], and raised [[jugular venous pressure]].<ref name=Goldhaber/> A low-grade [[fever]] may be present, particularly if there is associated pulmonary hemorrhage or infarction.<ref>{{cite journal |author=Stein PD, Sostman HD, Hull RD, ''et al.'' |title=Diagnosis of Pulmonary Embolism in the Coronary Care Unit |journal=Am. J. Cardiol. |volume=103 |issue=6 |pages=881–6 |year=2009 |month=March |pmid=19268750 |pmc=2717714 |doi=10.1016/j.amjcard.2008.11.040}}</ref>