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Pulmonary Thromboembolism (view source)
Revision as of 09:31, 28 September 2011
, 09:31, 28 September 2011Created page with "==Introduction== Pulmonary thromboembolism describes the '''occlusion of pulmonary vessels by a clot'''. It has usually arisen from the systemic venous circulation, embolises to ..."
==Introduction==
Pulmonary thromboembolism describes the '''occlusion of pulmonary vessels by a clot'''. It has usually arisen from the systemic venous circulation, embolises to the pulmonary circulation and causes obstruction of the arterial supply to an area of the lung. This results in '''ventilation perfusion mismatch''' occuring where there are areas of the lung which continue to be ventilated but do not receive adequate blood supply. This can result in '''severe hypoxia''' and marked signs of respiratory distress if the area of underperfused but ventilated lung is large.
It can lead to pulmonary hypertension and result in pleural effusion.
'''Causes''' of pulmonary thromboembolism include:
:'''Cardiac disease''': ''[[Dirofilaria immitis]]'', [[Dilated Cardiomyopathy|dilated cardiomyopathy]], [[Mitral Valve Dysplasia|chronic mitral valve insufficiency]], [[Endocarditis|endocarditis]]
:'''Neoplasia''': lymphosarcoma, bronchoalveolar carcinoma, pancreatic carcinoma
:'''[[Disseminated Intravascular Coagulation]]'''
:'''Sepsis'''
:'''[[Hyperadrenocorticism]]'''
:'''Protein-losing nephropathy''': [[Amyloidosis|amyloidosis]], [[Glomerulonephritis|glomerulonephritis]]
:'''[[Protein Losing Enteropathy|Protein-losing enteropathy]]'''
:'''[[Pancreatitis]]'''
:'''[[Pulmonary Infiltration with Eosinophilia|Eosinophilic lung disease]]'''
:'''Air emboli'''
:'''[[Immune Mediated Haemolytic Anaemia|Autoimmune haemolytic anaemia]]'''
:'''Iatrogenic''': indwelling vascular catheters, transfusions
:'''Idiopathic'''
==Clinical Signs==
Usually '''non-specific'''.
There may be an acute onset of '''respiratory distress''', with increased depth, rate and effort of breathing.
Patients may also present with an acute onset of signs of '''right sided heart failure''' due to the sudden increase in pulmonary vascular resistance.
There may be signs of an '''underlying disease''' such as Cushing's or intestinal disease.
==Diagnosis==
Diagnosis is '''difficult ante-mortem'''.
'''History and clinical signs''' are usually vague and non-specific.
'''Radiography''' may demonstrate a diminution or loss of peripheral vessels and an increase in size of the central pulmonary artery, but are often normal.
'''Blood gas analysis''' will reveal the ventilation perfusion mismatch and there will be hypoxemia, hypocapnia and respiratory alkalosis.
'''Nuclear perfusion scintigraphy''' is a safe and sensitive test and will detect if there is a lack of perfusion of part of the lung.
==Treatment==
This primarily involves '''treating the underlying cause'''.
'''Supportive care''' includes oxygen supplementation, strict cage confinement and careful parenteral fluid therapy..
'''Anticoagulant therapy''' should be considered in severe cases to prevent extension of the clot within the pulmonary circulation.
'''Heparin''' has a rapid onset and short-term effects.
'''Fibrinolytic therapy''' is very expensive and lacks selectivity, but includes drugs such as streptokinase, urokinase and tissue plasminogen activator.
'''Prognosis''' is poor to guarded in cats and dogs. Recurrence is possible, especially if the cause has not been resolved.
{{Learning
|flashcards = [[Small Animal Abdominal and Metabolic Disorders Q&A 01]]
}}
==References==
Pasquini, C. (1999) '''Tschauner's Guide to Small Animal Clinics''' ''Sudz Publishing''
Boswood, A. (2010) '''Pulmonary parenchymal disease''' ''RVC Student Notes''
[[Category:To Do - Helen]]
[[Category:To Do - Review]]
Pulmonary thromboembolism describes the '''occlusion of pulmonary vessels by a clot'''. It has usually arisen from the systemic venous circulation, embolises to the pulmonary circulation and causes obstruction of the arterial supply to an area of the lung. This results in '''ventilation perfusion mismatch''' occuring where there are areas of the lung which continue to be ventilated but do not receive adequate blood supply. This can result in '''severe hypoxia''' and marked signs of respiratory distress if the area of underperfused but ventilated lung is large.
It can lead to pulmonary hypertension and result in pleural effusion.
'''Causes''' of pulmonary thromboembolism include:
:'''Cardiac disease''': ''[[Dirofilaria immitis]]'', [[Dilated Cardiomyopathy|dilated cardiomyopathy]], [[Mitral Valve Dysplasia|chronic mitral valve insufficiency]], [[Endocarditis|endocarditis]]
:'''Neoplasia''': lymphosarcoma, bronchoalveolar carcinoma, pancreatic carcinoma
:'''[[Disseminated Intravascular Coagulation]]'''
:'''Sepsis'''
:'''[[Hyperadrenocorticism]]'''
:'''Protein-losing nephropathy''': [[Amyloidosis|amyloidosis]], [[Glomerulonephritis|glomerulonephritis]]
:'''[[Protein Losing Enteropathy|Protein-losing enteropathy]]'''
:'''[[Pancreatitis]]'''
:'''[[Pulmonary Infiltration with Eosinophilia|Eosinophilic lung disease]]'''
:'''Air emboli'''
:'''[[Immune Mediated Haemolytic Anaemia|Autoimmune haemolytic anaemia]]'''
:'''Iatrogenic''': indwelling vascular catheters, transfusions
:'''Idiopathic'''
==Clinical Signs==
Usually '''non-specific'''.
There may be an acute onset of '''respiratory distress''', with increased depth, rate and effort of breathing.
Patients may also present with an acute onset of signs of '''right sided heart failure''' due to the sudden increase in pulmonary vascular resistance.
There may be signs of an '''underlying disease''' such as Cushing's or intestinal disease.
==Diagnosis==
Diagnosis is '''difficult ante-mortem'''.
'''History and clinical signs''' are usually vague and non-specific.
'''Radiography''' may demonstrate a diminution or loss of peripheral vessels and an increase in size of the central pulmonary artery, but are often normal.
'''Blood gas analysis''' will reveal the ventilation perfusion mismatch and there will be hypoxemia, hypocapnia and respiratory alkalosis.
'''Nuclear perfusion scintigraphy''' is a safe and sensitive test and will detect if there is a lack of perfusion of part of the lung.
==Treatment==
This primarily involves '''treating the underlying cause'''.
'''Supportive care''' includes oxygen supplementation, strict cage confinement and careful parenteral fluid therapy..
'''Anticoagulant therapy''' should be considered in severe cases to prevent extension of the clot within the pulmonary circulation.
'''Heparin''' has a rapid onset and short-term effects.
'''Fibrinolytic therapy''' is very expensive and lacks selectivity, but includes drugs such as streptokinase, urokinase and tissue plasminogen activator.
'''Prognosis''' is poor to guarded in cats and dogs. Recurrence is possible, especially if the cause has not been resolved.
{{Learning
|flashcards = [[Small Animal Abdominal and Metabolic Disorders Q&A 01]]
}}
==References==
Pasquini, C. (1999) '''Tschauner's Guide to Small Animal Clinics''' ''Sudz Publishing''
Boswood, A. (2010) '''Pulmonary parenchymal disease''' ''RVC Student Notes''
[[Category:To Do - Helen]]
[[Category:To Do - Review]]