Pulmonary embolism, abbreviated PE, is often on the differential in autopsies, as it is not easy to diagnose clinically. Pulmonary embolism is a non-specific term; it may refer to a number of things, including:
- Pulmonary venous thromboembolism.
- Pulmonary fat embolism.
- Pulmonary foreign body embolism.
- Pulmonary septic embolism.
- Pulmonary bone marrow embolism.
- Pulmonary tumour embolism.
- Pulmonary amniotic fluid embolism.
PE usually refers to pulmonary venous thromboembolism, abbreviated VTE, if not otherwise specified.
- Relatively uncommon ~ 1 in 1000 adults per year.
- Diagnosis in life dependent on strong clinical suspicion and radiology.
- Shortness of breath (dyspnea) - classic symptom.
- Chest pain.
- Findings associated with deep vein thrombosis.
- Leg pain.
- Leg swelling.
- Venous thrombosis OR~=12 for PE.
- Endothelial dysfunction/injury.
- The triad has a limited practical use. Like many questions about mechanism, the greatest utility, might be pimping medical students and residents.
Risks factors venous thromboembolism
A general mnemonic for hypercoagulable states PIANO:
Hypercoagulable states due to intrinsic causes (memory device CALM SHAPES):
- Protein C deficiency.
- Antiphospholipid antibody syndrome (APLA).
- Leiden factor V deficiency.
- Protein S deficiency.
- Antithrombin III deficiency.
- Prothrombin G20210A.
- Excess factor VIII.
- Sticky platelet syndrome.
- Intravascular spaghetti (multiple cylindrical clots - from smaller vessels) with cream sauce (gray fibrin).
- Leg swelling.
- Lines of Zahn.
- Pale layers consisting of platelets and fibrin alternating with layers of RBCs; components layer during blood flow.
- Post-mortem thrombi: one (superior) yellow portion (called "chicken fat") and one (dependent) red portion (RBCs); components layer due to gravity.
Pre- and post-mortem clots
|Adherent to wall||yes||no|
|Colour||gray||dark purple or|
|Pressurized||yes; "ejects itself" from lumen||no; needs to be pulled-out|
-elastic modulus (E)
-fracture toughness (K)
|firm (high E)
brittle (low K)
|jello (low E)|
elastic (high K)
|Image - gross||thrombus (pathguy.com),
|coronary thrombus (luc.edu)|
|Image - micro.||pre- & post-mortem (elsevier.es)||thrombus (oxfordjournals.org), |
- Layers consisting of platelets and fibrin alternating with layers of RBCs - known as Lines of Zahn.
- Multiple laminations (layers), in general, suggest that clot was formed in a dynamic environment, i.e. in the context of blood flow.
Microscopic (fat embolism)
- Fat in vessels.
Microscopic (amniotic fluid)
- Pulmonary vessels with fetal debris - particularly squamous cells.
- Meetoo, D.. "In too deep: understanding, detecting and managing DVT.". Br J Nurs 19 (16): 1021-7. PMID 20852464.
- Reissig A, Haase U, Schulze E, Lehmann T, Kroegel C (July 2010). "[Diagnosis and therapy of pulmonary embolism prior to death]" (in German). Dtsch. Med. Wochenschr. 135 (30): 1477–83. doi:10.1055/s-0030-1262435. PMID 20648405.
- Reitsma, PH.; Versteeg, HH.; Middeldorp, S. (Mar 2012). "Mechanistic view of risk factors for venous thromboembolism.". Arterioscler Thromb Vasc Biol 32 (3): 563-8. doi:10.1161/ATVBAHA.111.242818. PMID 22345594.
- URL: http://www.usmle-forums.com/usmle-step-1-mnemonics/252-causes-hypercoagulable-states.html. Accessed on: 8 December 2011.
- Thomas RH (November 2001). "Hypercoagulability syndromes". Arch. Intern. Med. 161 (20): 2433–9. PMID 11700155. http://archinte.highwire.org/cgi/content/full/161/20/2433.
- Online 'Mendelian Inheritance in Man' (OMIM) 176930
- Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 124. ISBN 978-1416031215.
- URL: http://www.meddean.luc.edu/lumen/meded/mech/cases/case1/list.htm. Accessed on 8 October 2010.
- URL: http://www.elsevier.es/cardio_eng/ctl_servlet?_f=40&ident=13142654. Accessed on: 8 October 2010.
- URL: http://library.med.utah.edu/WebPath/EXAM/IMGQUIZ/fofrm.html. Accessed on: 6 December 2010.
- ATTWOOD, HD. (Jul 1958). "The histological diagnosis of amniotic-fluid embolism.". J Pathol Bacteriol 76 (1): 211-5. PMID 13576364.
- Kobayashi, H.; Ooi, H.; Hayakawa, H.; Arai, T.; Matsuda, Y.; Gotoh, K.; Tarao, T. (Apr 1997). "Histological diagnosis of amniotic fluid embolism by monoclonal antibody TKH-2 that recognizes NeuAc alpha 2-6GalNAc epitope.". Hum Pathol 28 (4): 428-33. PMID 9104942.