Lung nontumor
Other nonneoplastic disease
Infarct / pulmonary emboli

Topic Completed: 1 December 2011

Revised: 30 January 2019, last major update December 2011

Copyright: (c) 2003-2017,, Inc.

PubMed search: pulmonary emboli [title] OR pulmonary infarct [title]

Elliot Weisenberg, M.D.
Page views in 2019: 7,617
Page views in 2020 to date: 4,132
Cite this page: Weisenberg E. Infarct / pulmonary emboli. website. Accessed July 7th, 2020.
Clinical features
  • 50,000+ deaths / year in US due to pulmonary emboli (major cause of death in 10% of adults dying acutely in hospitals)
  • 95% of emboli are from deep leg veins; often in immobilized individuals; also central venous lines may cause right atrial thrombi
  • Occlusions usually embolic, not thrombotic, as pulmonary vasculature is low pressure, uncommonly occurs with pulmonary hypertension
  • Autopsy studies show incidence in general population of 1%, including 30% of patients with severe burns or trauma
  • Large emboli cause sudden death by (a) lodging in major branches of pulmonary arteries or at bifurcations, causing electromechanical dissociation with rhythm but no pulse or (b) acute cor pulmonale (dilation of right side of heart) due to local increased resistance to blood flow, pulmonary hypertension and right sided failure
  • Other risk factors are trauma, hypercoagulable states, protein C/S deficiency, lupus anticoagulant, Factor V Leiden mutation, prothrombin mutation, carcinoma and Trousseau's syndrome, oral contraceptives, heart failure, pregnancy and older age
  • Small infarcts usually have minimal symptoms; if bronchial circulation is inadequate (so reduced collateral circulation), then have shortness of breath, tachycardia, pain, fever, cough, hemoptysis, fibrinous pleuritis or friction rub
  • If cardiovascular function is adequate, bronchial artery may compensate for pulmonary emboli, leading to hemorrhage without infarction; lungs can recover from hemorrhage but not from infarction
  • Emboli cause infarction only when circulation is already inadequate, so rare in young
  • Fat emboli: due to long bone fracture or CPR
  • Amniotic fluid emboli: rare pregnancy complication, with squames in vessels
  • Hypercoagulable states: either primary (deficiency of antithrombin III or protein C, lupus anticoagulant, Factor V Leiden mutation, prothrombin mutation, defective fibrinolysis) or secondary (obesity, surgery, cancer, estrogen and pregnancy)
  • Although other tests may be more sensitive, D-dimer testing is an excellent validated screening test for thromboembolic disease; a negative result essentially rules out pulmonary embolism
  • CT angiography: Very sensitive and specific, fast and readily available imaging study to rule in or rule out pulmonary embolism; has essentially replaced conventional angiography
  • Chest Xray: wedge shaped infarct after 12 - 36 hours; may simulate carcinoma
  • Nuclear scan: macroaggregates of labeled albumin with perfusion lung scanning; angiography most definitive diagnostic test
Gross description
  • Wedge shaped, hemorrhagic parenchyma and fibrinous pleural exudate; eventually scars
Gross images

Images hosted on other servers:

Thromboemboli in pulmonary artery

Saddle embolus

Hemorrhagic infarct

Organizing infarct

Fibrous band

Microscopic (histologic) description
  • Neutrophils present if septic emboli
Microscopic (histologic) images

Images hosted on other servers:


Small thromboemboli

With recanalization

Left: fat emboli; right: amniotic fluid emboli

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