Pulmonary Embolism: Difference between revisions

mNo edit summary
(Page update IP)
Line 8: Line 8:
== Introduction  ==
== Introduction  ==


Pulmonary embolism (PE) is responsible for most mortality as it's diverse range of clinical presentation and sometimes asymptomatic presentation creates room for challenges in the diagnoses. It is medical emergence and prompt diagnosis and treatment are vital in reducing mortality and associated morbidity.
Pulmonary embolism (PE) is a blockage of one of the pulmonary arteries in the lungs. In most cases, a deep venous thrombosis (DVT) forms in the leg. Once dislodged, the thrombus travels to the lungs where it occludes the pulmonary artery. The condition is a medical emergency that requires prompt diagnosis and treatment.  


== Causal Factors ==
== Pathological Process ==
* The main cause of PE is thrombosis dislodge and circulating in the blood stream to occlude the pulmonary artery. Blood clot can occur due to serious limb injury, surgery, prolonged bed rest and static lower limb posture for more than  6 hours.
Thrombus formation occurs due to stasis in the deep veins, especially at the calf. The patient's initial cardiorespiratory status, and size and number of emboli affects the severity of changes in pulmonary blood flow and respiration. A small blockage of the pulmonary artery may not provoke symptoms, while a large embolus can be fatal. 
* Cancer or cancer treatments such as chemotherapy and radiotherapy could lead to possible thrombosis formation
 
* Other factors are overweight and hypercholesterolemia  as it could lead to fat embolism; pregnancy as there an increase rick of PE  to in the first few weeks postpartum; smoking; some hormone replacement therapy (HRT).
In the latter case, pulmonary embolism causes wasted ventilation as it increases the alveoli dead space, resulting in a ventilation-perfusion mismatch<ref name=":2">Hough, A. Physiotherapy in Respiratory Care; An evidence-based approach to respiratory and cardiac management. 3<sup>rd</sup> eds. United Kingdom: Nelson Thomes Ltd, 2001 </ref> and an increase in pulmonary artery pressures and right ventricular work.<ref name=":5">Hillegass E. Essential of Cardiopulmonary Physical Therapy. 3rd ed. Missouri,St. Louis: Saunders Elsevier. 2011</ref> Consequently, there is eventual right heart failure, accompanied by the left side of the heart due to decrease in blood volume and coronary perfusion to the left ventricle. Cardiac muscle dysfunction ensues, and the heart ceases to pump blood.{{#ev:youtube|XKT6gHI2z4U|400}}<ref>MedCram. Pulmonary Embolism Remastered - Pathophysiology, Symptoms, Diagnosis, DVT. Available from: http://www.youtube.com/watch?v=XKT6gHI2z4U[last accessed 29/4/2019]</ref>
* Hyper-coagulation of blood<ref>What Else Could Raise My Chances of PE? Available from: https://www.webmd.com/lung/what-is-a-pulmonary-embolism [Accessed 29th April 2019].
</ref>
* PE can also arise from the right side of the [[Anatomy of the Human Heart|heart]]
* Non-thrombotic materials such as amniotic fluid, fat, air, bone and organ fragments.
{{#ev:youtube|XKT6gHI2z4U|400}}<ref>MedCram. Pulmonary Embolism Remastered - Pathophysiology, Symptoms, Diagnosis, DVT. Available from: http://www.youtube.com/watch?v=XKT6gHI2z4U[last accessed 29/4/2019]</ref>
== Mechanism of Injury / Pathological Process  ==


The initial cardiorepiratory state and size and number of emboli affects the severity of the of the change in pulmonary blood flow and respiration. a small blockage of the pulmonary artery may not be symptomatic  but a large emboli can lead to several events which are deleterious the the individual.  Thrombosis formation occur due to stasis in the deep veins especially the vein at the calf. Blood stasis leads to thrombosis been formed and it's dislodge makes it to circulate freely in the blood as an embolus and can occlude blood vessels; most especially the pulmonary artery.  The occlusion can also be as a result of other emboli like air bolus , fat e.t.c. Pulmonary embolism causes wasted ventilation as it increases the alveoli dead space thus resulting in ventilation perfusion mismatch<ref name=":2">Hough, A. Physiotherapy in Respiratory Care; An evidence-based approach to respiratory and cardiac management. 3<sup>rd</sup> eds. United Kingdom: Nelson Thomes Ltd, 2001 </ref> and an increase in pulmonary artery pressures and right ventricular work.<ref name=":5">Hillegass E. Essential of Cardiopulmonary Physical Therapy. 3rd ed. Missouri,St. Louis: Saunders Elsevier. 2011</ref> Consequently, there is eventual right heart failure, accompanied by the left side of the heart due to decrease in  blood volume and coronary perfusion to the left ventricle. Cardiac muscle dysfunction ensues; thus, the heart ceases to pump blood.<br>
In rare cases, occlusion of the pulmonary artery can also occur due to non-thrombotic materials such as air, fat, amniotic fluid, bone, and organ fragments.


== Prevalence/Incidence of PE ==
== Prevalence/Incidence of PE ==
After [[Myocardial Infarction|myocardial infarction (MI)]] and [https://www.who.int/topics/cerebrovascular_accident/en/ cerebrovascular accidents (CVA)], PE follows as the third leading cause of cardiovascular death.<ref>Weitz JI. Pulmonary embolism. In: Goldman L, Schafer AI, editors. Goldman's Cecil Medicine. 24th efition. Philadelphia, PA: Elsevier; 2011</ref> Some persons with PE are asymptomatic with incidence of 2.6%<ref name=":4" /> and upto 71.4% in patient with distal [[DVT and PE in individuals with SCI|DVT]].<ref name=":0" /> The European guidelines for the diagnosis and management of PE report annual incidence rates of venous thrombosis and PE of approximately 0.5 to 1.0 per 1000 inhabitants. A national incidence of 0.6/1000/year was reported by a study done by swedish in 2005<ref>Andersson T, Söderberg S. Incidence of acute pulmonary embolism, related comorbidities and survival; analysis of a Swedish national cohort. BMC Cardiovasc Disord. 2017; 17: 155. doi: 10.1186/s12872-017-0587-1
After [[Myocardial Infarction|myocardial infarction (MI)]] and [https://www.who.int/topics/cerebrovascular_accident/en/ cerebrovascular accidents (CVA)], PE follows as the third leading cause of cardiovascular death.<ref>Weitz JI. Pulmonary embolism. In: Goldman L, Schafer AI, editors. Goldman's Cecil Medicine. 24th efition. Philadelphia, PA: Elsevier; 2011</ref> Some persons with PE are asymptomatic with incidence of 2.6%<ref name=":4">Dentali F, Ageno W, Becattini C, Galli L, Gianni M, Riva N et al. Prevalence and clinical history of incidental, asymptomatic pulmonary embolism: a meta-analysis.Thromb Res. 2010;125(6):518-22. doi: 10.1016/j.thromres.2010.03.016. </ref> and upto 71.4% in patient with distal [[DVT and PE in individuals with SCI|DVT]].<ref name=":0">Krutman M, Wolosker N, Kuzniec S, de Campos Guerra JC, Tachibana A, de Almeida Mendes C. Risk of asymptomatic pulmonary embolism in patients with deep venous thrombosis. J Vasc Surg Venous Lymphat Disord. 2013;1(4):370-5. doi: 10.1016/j.jvsv.2013.04.002.
</ref> The European guidelines for the diagnosis and management of PE report annual incidence rates of venous thrombosis and PE of approximately 0.5 to 1.0 per 1000 inhabitants. A national incidence of 0.6/1000/year was reported by a Swedish study done in 2005.<ref>Andersson T, Söderberg S. Incidence of acute pulmonary embolism, related comorbidities and survival; analysis of a Swedish national cohort. BMC Cardiovasc Disord. 2017; 17: 155. doi: 10.1186/s12872-017-0587-1
</ref>
</ref>
== Risk Factors ==
Thrombi, or blood clots, are due to hypercoagulation. Common risk factors include in the following:<ref>What Else Could Raise My Chances of PE? Available from: https://www.webmd.com/lung/what-is-a-pulmonary-embolism [Accessed 29th April 2019].
</ref><ref name=":3">Tapson VF. Acute pulmonary embolism. New England Journal of Medicine. 2008 Mar 6;358(10):1037-52.</ref>
* Serious limb injury, surgery, prolonged bed rest, and static lower limb posture for more than 6 hours
* Trauma and spinal cord injury
* Smoking
* Oral contraceptives
* Hormone replacement therapy
* Cancer
* Chemotherapy
* Pregnancy and post-partum period
* Advanced age (>40 years old)
* Immobilizer or cast
* Central venous catheterization
Being overweight and hypercholesterolemia increase the risk of fat embolism.


== Clinical Presentation<ref name=":2" />  ==
== Clinical Presentation<ref name=":2" />  ==
Line 41: Line 52:
* Cyanosis
* Cyanosis


== Diagnostic Procedures  ==
Several prediction tools can be used to help clinicians assess a patient's likelihood of having PE:<ref name=":1">Essers BA, Prins MH. Methods to measure treatment satisfaction in patients with pulmonary embolism or deep venous thrombosis. Curr Opin Pulm Med. 2010;16(5):437-41.  
 
PE is difficult to diagnose clinically<ref name=":3">Pryor JA, Webber BA. Eds. Physiotherapy for Respiratory and Cardiac problems. 2<sup>nd</sup>edition. Churchill Livingstone, London. 1998; p47</ref> as only few cases show the triad of chest pain, dyspnoea and haemoptysis <ref>Goldstein M, Cornil A. Clinical diagnosis of pulmonary embolism.Acta Chir Belg. 1986;86(2):79-83.
</ref> and some are even unsymptomatic with incidence of 2.6%<ref name=":4">Dentali F, Ageno W, Becattini C, Galli L, Gianni M, Riva N et al. Prevalence and clinical history of incidental, asymptomatic pulmonary embolism: a meta-analysis.Thromb Res. 2010;125(6):518-22. doi: 10.1016/j.thromres.2010.03.016. </ref> and up to 71.4% in patient with distal DVT.<ref name=":0">Krutman M, Wolosker N, Kuzniec S, de Campos Guerra JC, Tachibana A, de Almeida Mendes C. Risk of asymptomatic pulmonary embolism in patients with deep venous thrombosis. J Vasc Surg Venous Lymphat Disord. 2013;1(4):370-5. doi: 10.1016/j.jvsv.2013.04.002.  
</ref>
</ref>
* [https://www.mdcalc.com/wells-criteria-dvt Wells Prediction Score]
* Geneva Score
* [https://www.mdcalc.com/geneva-score-revised-pulmonary-embolism Revised Geneva Score]


A test such as '''D-dimer and Doppler Ultrasound'''.to for thrombosis as more than 70% of patients with PE also has [[Deep Vein Thrombosis|DVT]]<ref>Edmondson, R. The causes and management
== Preliminary Lab Testing ==


of pulmonary embolism. Care Crit. Ill. 1194; 10:26-9.
Suspicion of PE should be based on a careful assessment of history, known risk factors, and physical examination.<ref name=":3" /> From there, additional studies must be performed to confirm a diagnosis.
</ref><ref name=":0" /> with sensitivity of 86% and a specificity of 96% with a diagnostic accuracy of 95%.<ref>Kory PD, Pellecchia CM, Shiloh AL, Mayo PH, DiBello C, Koenig S. Accuracy of ultrasonography performed by critical care physicians for the diagnosis of DVT. Chest. 2011;139(3):538–42.</ref>


Chest  X-ray may show a small pleural effusion or a peripheral wedge-shaped shadow indicating infarcted lung<ref>Elliott CG, Goldhaber SZ, Visani L, DeRosa M. Chest radiographs in acute pulmonary embolism. Results from the International Cooperative Pulmonary Embolism Registry. Chest. 2000;118(1):33-8.
D-dimer and doppler ultrasound are non-specific tests that can rule in DVT and PE as possible diagnoses.<ref>Edmondson, R. The causes and management
</ref>.<ref>Shawn TSH, Yan LX, Lateef F. The chest X ray in pulmonary embolism: Westermark sign, Hampton's Hump and Palla's sign. What's the difference? Journal of Acute Disease. 2018; 7(3): 99-102
</ref>


Ventilation/perfusion (V/Q) scan and 50% accurate
of pulmonary embolism. Care Crit. Ill. 1194; 10:26-9.
 
</ref><ref name=":0" /> Electrocardiography can identify heart abnormalities that are more common with large embolisms.<ref name=":3" /> Likewise, in conjunction with other cardiac tests, elevated cardiac troponins may increase suspicion of a massive embolism. Although, Chest X-rays are non-diagnostic, they are important for ruling out or uncovering alternative diagnoses such as pleural effusion.<ref>Elliott CG, Goldhaber SZ, Visani L, DeRosa M. Chest radiographs in acute pulmonary embolism. Results from the International Cooperative Pulmonary Embolism Registry. Chest. 2000;118(1):33-8.
Pulmonary angiography<ref name=":3" />
</ref><ref>Shawn TSH, Yan LX, Lateef F. The chest X ray in pulmonary embolism: Westermark sign, Hampton's Hump and Palla's sign. What's the difference? Journal of Acute Disease. 2018; 7(3): 99-102
 
</ref>
Computed tomographic angiography (CTA) which is a spiral CT with intravenous contrast medium is the best diagnostic tool as it is 90% conclusive.
 
MRI is another option used if there is fear of harm from other procedures especially in pregnant women.


A PE Rule-out Criteria could be used in out patient emergency<ref>Kline JA, Courtney DM, Kabrhel C, Moore CL, Smithline HA, Plewa MC et al. Prospective multicenter evaluation of the pulmonary embolism rule-out criteria. J Thromb Haemost. 2008;6(5):772–80</ref> as a clinical decision rule.
== Diagnostic Imaging ==
 
Many imaging studies can be used to diagnose PE.<ref name=":3" /> Among the most common are ventilation-perfusion scanning, computed tomographic angiography (CTA), and magnetic resonance imaging (MRI). CTA is the best diagnostic tool, as it is has the greatest specificity and sensitivity for detecting emboli in the pulmonary arteries.<ref name=":3" />
== Outcome Measures  ==
* Duke Anticoagulation Satisfaction Scale (DASS) <ref name=":1">Essers BA, Prins MH. Methods to measure treatment satisfaction in patients with pulmonary embolism or deep venous thrombosis. Curr Opin Pulm Med. 2010;16(5):437-41.
</ref><ref>Samsa G, Matchar DB, Dolor RJ, Wiklund I. Hedner E, Wygant G et al. A new instrument for measuring anticoagulation-related quality of life: development and preliminary validation. Health Qual Life Outcomes. 2004; 2: 22. doi: 10.1186/1477-7525-2-22
</ref>
* Perception of Anticoagulation Treatment Questionnaire (PACT-Q).<ref name=":1" />


== Management / Interventions  ==
Ventilation-perfusion scanning is also highly diagnostic in the absence of cardiopulmonary disease. Per a review by the New England Journal of Medicine<ref name=":3" />, under high clinical suspicion, "a normal perfusion lung scan effectively rules out acute pulmonary embolism."


'''Anticoagulant Therapy'''<ref name=":5" />
== Medical Management  ==


A fast acting fibrinolytic agent such as heparin should be administered. Heparin prevents blood clot progression.
Once diagnosed, a variety of medical interventions may be used to manage PE.


'''Sedation'''<ref name=":5" />
'''Anticoagulant Therapy'''


A sedative to decrease the patient’s anxiety and pain;
Anticoagulation is among the most common treatments for PE.<ref name=":5" /><ref name=":3" /> Fast-acting fibrinolytic agents such as heparin or pentasaccharide fondaparinux are typically administered.<ref name=":3" /> These medications are prescribed with the goal of preventing blood clot progression.


'''Oxygen Therapy'''
'''Inferior Vena Cava Placement'''


Oxygen to reduces the pulmonary artery pressure and improve PAO<sub>2</sub>.
An IVC filter may be placed  in patients with recurrent PE, contraindications to anticoagulation, or major bleeding complications with anticoagulation.<ref name=":3" /> Although IVC filters can effectively reduce the incidence of PE, they may increase the incidence of DVT.


'''Embolectomy'''
'''Embolectomy'''

Revision as of 04:03, 3 July 2020

Original Editor Uchechukwu Chukwuemeka

Top Contributors - Uchechukwu Chukwuemeka, Karen Wilson, Rachael Lowe, Kim Jackson and Lucinda hampton


Introduction[edit | edit source]

Pulmonary embolism (PE) is a blockage of one of the pulmonary arteries in the lungs. In most cases, a deep venous thrombosis (DVT) forms in the leg. Once dislodged, the thrombus travels to the lungs where it occludes the pulmonary artery. The condition is a medical emergency that requires prompt diagnosis and treatment.

Pathological Process[edit | edit source]

Thrombus formation occurs due to stasis in the deep veins, especially at the calf. The patient's initial cardiorespiratory status, and size and number of emboli affects the severity of changes in pulmonary blood flow and respiration. A small blockage of the pulmonary artery may not provoke symptoms, while a large embolus can be fatal. 

In the latter case, pulmonary embolism causes wasted ventilation as it increases the alveoli dead space, resulting in a ventilation-perfusion mismatch[1] and an increase in pulmonary artery pressures and right ventricular work.[2] Consequently, there is eventual right heart failure, accompanied by the left side of the heart due to decrease in blood volume and coronary perfusion to the left ventricle. Cardiac muscle dysfunction ensues, and the heart ceases to pump blood.

[3]

In rare cases, occlusion of the pulmonary artery can also occur due to non-thrombotic materials such as air, fat, amniotic fluid, bone, and organ fragments.

Prevalence/Incidence of PE[edit | edit source]

After myocardial infarction (MI) and cerebrovascular accidents (CVA), PE follows as the third leading cause of cardiovascular death.[4] Some persons with PE are asymptomatic with incidence of 2.6%[5] and upto 71.4% in patient with distal DVT.[6] The European guidelines for the diagnosis and management of PE report annual incidence rates of venous thrombosis and PE of approximately 0.5 to 1.0 per 1000 inhabitants. A national incidence of 0.6/1000/year was reported by a Swedish study done in 2005.[7]

Risk Factors[edit | edit source]

Thrombi, or blood clots, are due to hypercoagulation. Common risk factors include in the following:[8][9]

  • Serious limb injury, surgery, prolonged bed rest, and static lower limb posture for more than 6 hours
  • Trauma and spinal cord injury
  • Smoking
  • Oral contraceptives
  • Hormone replacement therapy
  • Cancer
  • Chemotherapy
  • Pregnancy and post-partum period
  • Advanced age (>40 years old)
  • Immobilizer or cast
  • Central venous catheterization

Being overweight and hypercholesterolemia increase the risk of fat embolism.

Clinical Presentation[1][edit | edit source]

  • Pyrexia
  • Dyspnea and/or Tachypnea
  • Crackle lung sound on chest auscultation
  • Prounced second heart sound
  • Pleuritic chest pain
  • Profuse sweating
  • Cough with hemoptysis
  • Tachycardia with rapid feeble pulse, arrhythmia
  • Hypotension, lightheadedness, dizziness (occasionally induced
  • by exercise only)
  • Syncope
  • Cyanosis

Several prediction tools can be used to help clinicians assess a patient's likelihood of having PE:[10]

Preliminary Lab Testing[edit | edit source]

Suspicion of PE should be based on a careful assessment of history, known risk factors, and physical examination.[9] From there, additional studies must be performed to confirm a diagnosis.

D-dimer and doppler ultrasound are non-specific tests that can rule in DVT and PE as possible diagnoses.[11][6] Electrocardiography can identify heart abnormalities that are more common with large embolisms.[9] Likewise, in conjunction with other cardiac tests, elevated cardiac troponins may increase suspicion of a massive embolism. Although, Chest X-rays are non-diagnostic, they are important for ruling out or uncovering alternative diagnoses such as pleural effusion.[12][13]

Diagnostic Imaging[edit | edit source]

Many imaging studies can be used to diagnose PE.[9] Among the most common are ventilation-perfusion scanning, computed tomographic angiography (CTA), and magnetic resonance imaging (MRI). CTA is the best diagnostic tool, as it is has the greatest specificity and sensitivity for detecting emboli in the pulmonary arteries.[9]

Ventilation-perfusion scanning is also highly diagnostic in the absence of cardiopulmonary disease. Per a review by the New England Journal of Medicine[9], under high clinical suspicion, "a normal perfusion lung scan effectively rules out acute pulmonary embolism."

Medical Management[edit | edit source]

Once diagnosed, a variety of medical interventions may be used to manage PE.

Anticoagulant Therapy

Anticoagulation is among the most common treatments for PE.[2][9] Fast-acting fibrinolytic agents such as heparin or pentasaccharide fondaparinux are typically administered.[9] These medications are prescribed with the goal of preventing blood clot progression.

Inferior Vena Cava Placement

An IVC filter may be placed  in patients with recurrent PE, contraindications to anticoagulation, or major bleeding complications with anticoagulation.[9] Although IVC filters can effectively reduce the incidence of PE, they may increase the incidence of DVT.

Embolectomy

Physiotherapy

The role of physiotherapy comes in when embolism has been controlled and no further clot is been formed. The main aim of physiotherapy is to restore a clear lung field and oxygen uptake to optimal level.This could be achieved by appropriate chest Physiotherapy and then progressed to endurance exercises such as bicycle ergometry, threadmill , hydrotherapy e.t.c. see...

[14]

Differential Diagnosis[15][edit | edit source]

Resources[edit | edit source]

  • Tran HA, Gibbs H, Merriman E, Curnow JL, Young L, Bennett A et al. New guidelines from the Thrombosis and Haemostasis Society of Australia and New Zealand for the diagnosis and management of venous thromboembolism. Med J Aust. 2019; 210(5):227-235.
  • British Thoracic Society guidelines for the management of suspected acute pulmonary embolism. Thorax 2003;58(6):470-483.
  • Konstantinides SV, Torbicki A. Management of pulmonary embolism: recent evidence and the new European guidelines. European Respiratory Journal 2014 44: 1385-1390; DOI: 10.1183/09031936.00180414
  • https://academic.oup.com/ptj/article/96/2/143/2686356

References[edit | edit source]

  1. ↑ 1.0 1.1 Hough, A. Physiotherapy in Respiratory Care; An evidence-based approach to respiratory and cardiac management. 3rd eds. United Kingdom: Nelson Thomes Ltd, 2001
  2. ↑ 2.0 2.1 Hillegass E. Essential of Cardiopulmonary Physical Therapy. 3rd ed. Missouri,St. Louis: Saunders Elsevier. 2011
  3. ↑ MedCram. Pulmonary Embolism Remastered - Pathophysiology, Symptoms, Diagnosis, DVT. Available from: http://www.youtube.com/watch?v=XKT6gHI2z4U[last accessed 29/4/2019]
  4. ↑ Weitz JI. Pulmonary embolism. In: Goldman L, Schafer AI, editors. Goldman's Cecil Medicine. 24th efition. Philadelphia, PA: Elsevier; 2011
  5. ↑ Dentali F, Ageno W, Becattini C, Galli L, Gianni M, Riva N et al. Prevalence and clinical history of incidental, asymptomatic pulmonary embolism: a meta-analysis.Thromb Res. 2010;125(6):518-22. doi: 10.1016/j.thromres.2010.03.016.
  6. ↑ 6.0 6.1 Krutman M, Wolosker N, Kuzniec S, de Campos Guerra JC, Tachibana A, de Almeida Mendes C. Risk of asymptomatic pulmonary embolism in patients with deep venous thrombosis. J Vasc Surg Venous Lymphat Disord. 2013;1(4):370-5. doi: 10.1016/j.jvsv.2013.04.002.
  7. ↑ Andersson T, Söderberg S. Incidence of acute pulmonary embolism, related comorbidities and survival; analysis of a Swedish national cohort. BMC Cardiovasc Disord. 2017; 17: 155. doi: 10.1186/s12872-017-0587-1
  8. ↑ What Else Could Raise My Chances of PE? Available from: https://www.webmd.com/lung/what-is-a-pulmonary-embolism [Accessed 29th April 2019].
  9. ↑ 9.0 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 Tapson VF. Acute pulmonary embolism. New England Journal of Medicine. 2008 Mar 6;358(10):1037-52.
  10. ↑ Essers BA, Prins MH. Methods to measure treatment satisfaction in patients with pulmonary embolism or deep venous thrombosis. Curr Opin Pulm Med. 2010;16(5):437-41.
  11. ↑ Edmondson, R. The causes and management of pulmonary embolism. Care Crit. Ill. 1194; 10:26-9.
  12. ↑ Elliott CG, Goldhaber SZ, Visani L, DeRosa M. Chest radiographs in acute pulmonary embolism. Results from the International Cooperative Pulmonary Embolism Registry. Chest. 2000;118(1):33-8.
  13. ↑ Shawn TSH, Yan LX, Lateef F. The chest X ray in pulmonary embolism: Westermark sign, Hampton's Hump and Palla's sign. What's the difference? Journal of Acute Disease. 2018; 7(3): 99-102
  14. ↑ MedCram. Pulmonary Embolism / Thromboembolism Updates Explained Clearly. Available from: http://www.youtube.com/watch?v=XKT6gHI2z4U[last accessed 29/4/2019]
  15. ↑ Squizzato A, Luciani D, Rubboli A, Di Gennaro L, Landolfi R, De Luca C et al. Differential diagnosis of pulmonary embolism in outpatients with non-specific cardiopulmonary symptoms. Intern Emerg Med. 2013;8(8):695-702.
Retrieved from "https://www.physio-pedia.com/index.php?title=Pulmonary_Embolism&oldid=242234"