Changes

*Decreased outflow of venous blood

*Decreased outflow of venous blood

*Most commonly caused by left-sided or bilateral cardiac failure  

*Most commonly caused by left-sided or bilateral cardiac failure  

**Stagnant blood in pulmonary vessels -> red blood cells move into alveoli and are phagocytosed -> [[General Pathology - Pigmentation and Calcification#Haemosiderin|haemosiderin in macrophages]] (heart failure cells)  

**Stagnant blood in pulmonary vessels -> red blood cells move into alveoli and are phagocytosed -> [[Pigmentation and Calcification - Pathology#Haemosiderin|haemosiderin in macrophages]] (heart failure cells)  

*One-sided in post-mortem hypostatic congestion

*One-sided in post-mortem hypostatic congestion

*Acute pulmonary congestion is seen after barbiturate euthanasia

*Acute pulmonary congestion is seen after barbiturate euthanasia

**Undetected in many horses

**Undetected in many horses

**Haemorrhage is dorsocaudal, large brown areas

**Haemorrhage is dorsocaudal, large brown areas

**Micro - alveolar haemorrhage, macrophages containing [[General Pathology - Pigmentation and Calcification#Haemosiderin|haemosiderin]], mild interstitial fibrosis

**Micro - alveolar haemorrhage, macrophages containing [[Pigmentation and Calcification - Pathology#Haemosiderin|haemosiderin]], mild interstitial fibrosis

***From bacterial [[Endocardial - Pathology#Inflammatory-Endocarditis|endocarditis]], jugular thrombophlebitis, [[Liver Inflammatory - Pathology#Hepatic abscessation|hepatic abscesses]] etc.

***From bacterial [[Endocardial - Pathology#Inflammatory-Endocarditis|endocarditis]], jugular thrombophlebitis, [[Liver Inflammatory - Pathology#Hepatic abscessation|hepatic abscesses]] etc.

***May cause unexpected death if in large numbers

***May cause unexpected death if in large numbers

***May develop [[Lungs Inflammatory - Pathology|suppurative pneumonia]] -> [[Lungs Inflammatory - Pathology#Pulmonary abscesses|pulmonary abscesses]], [[Arterial Disease - Pathology#Inflammatory-Arteritis|arteritis]], [[General Pathology - Thrombosis|thrombosis]]

***May develop [[Lungs Inflammatory - Pathology|suppurative pneumonia]] -> [[Lungs Inflammatory - Pathology#Pulmonary abscesses|pulmonary abscesses]], [[Arterial Disease - Pathology#Inflammatory-Arteritis|arteritis]], [[Thrombosis - Pathology|thrombosis]]

*Pulmonary infarcts usually occur when there is embolisation or thrombosis during general circulatory collapse or passive congestion of heart failure

*Pulmonary infarcts usually occur when there is embolisation or thrombosis during general circulatory collapse or passive congestion of heart failure

*Pulmonary thromboembolism is a sequel to in cattle to large emboli from liver abscesses close to the vena cava

*Pulmonary thromboembolism is a sequel to in cattle to large emboli from liver abscesses close to the vena cava