Changes

Fluid accumulation within the pericardial sac may lead to fibrous thickening and opacity of the pericardium if prolonged.  Villous proliferation of the serosa will occur due to the irritation caused by the presence of the fluid.

Fluid accumulation within the pericardial sac may lead to fibrous thickening and opacity of the pericardium if prolonged.  Villous proliferation of the serosa will occur due to the irritation caused by the presence of the fluid.

Large volumes of fluid within the pericardial sac may cause [[cardiac tamponade]].

Large volumes of fluid within the pericardial sac may cause [[Cardiac Tamponade - Pathology|cardiac tamponade]].

===Hydropericardium===

===Hydropericardium===

May also be associated with RTA trauma or ulcerative endocarditis due to uraemia in dogs with kidney failure.

May also be associated with RTA trauma or ulcerative endocarditis due to uraemia in dogs with kidney failure.

Death usually reults due to [[cardiac tamponade]].

Death usually reults due to [[Cardiac Tamponade - Pathology|cardiac tamponade]].

===Haemorrhagic effusion===

===Haemorrhagic effusion===

*Resolution with no further clinical significance.

*Resolution with no further clinical significance.

*Adhesion: organisation of fibrin.  May lead to a ''bread and butter'' appearance.

*Adhesion: organisation of fibrin.  May lead to a ''bread and butter'' appearance.

*Constriction: gradual [[cardiac tamponade]] will occur.

*Constriction: gradual [[Cardiac Tamponade - Pathology|cardiac tamponade]] will occur.