Category:Pericardial Pathology
The heart is invested in a pericardial sac with both visceral and parietal components. The visceral layer is closely adherent to the heart wall. The space within the pericardium is small and contains approximately 1-5ml serous fluid. This allows smooth movement of the heart within the pericardium during normal systole and diastole.
The pericardial sac is thin, fibrous and inelastic so prevents and significant distension. This causes a constrictive effect when fluid accumulates within the sac.
Pericardial disease accounts for only 1% of all clinically significant cardiac disease in the dog and cat, however it a frequently overlooked cause of right heart failure. Pericardial disease which is clinically significant is rare in the cat.
The most common congenital abnormality of the pericardium is Peritoneo-pericardial diaphragmatic hernia.
Other congenital abnormalities of the pericardial sac include:
- Pericardial cysts.
- Partial or complete absence of the paricardial sac.
Metabolic Pathology
Serous atrophy of fat
Epicardial mineralisation
Urate deposition
Hydropericardium
Haemopericardium
Haemorrhagic Effusion, Pericardial
Inflammatory-Pericarditis
Usually an infective aetiology. As with non-inflammatory accumulation of fluid the main complication is the restriction of ventricular movement. Clinical signs seen are therefore those of circulatory failure along with pyrexia and a general depression.
Spread of infectious agent may be:
- Haematogenous; following generalised infection. Most often seen in cattle and pigs.
- Extension of infection form surrounding tissues; for example from the lungs, pleura, mediastinum.
- Extension of infection from myocardium; rare.
- Traumatic penetration of the pericardium;
- Foreign bodies from the oesophagus or reticulum in cattle; traumatic reticulo-peritonitis.
- Fractured ribs; E.g. RTAs in small animals, horses etc.
Pericarditis can be subdivided into two main categories:
Fibrinous pericarditis
Most common form. Grey strands of fibrin cover the epicardium and little fluid accumulates. Close apposition of the parietal and visceral pericardium layers allows adhesion formation within approximatley 7-10 days. Such adhesions may resolve with little residual pathology or may become focal or diffuse adhesive pericarditis lesions.
Fibrinous pericarditis produces a crackiling sound on auscultation.
Suppurative pericarditis
Purulent pericarditis indicates the presence of pyogenic organisms E.g. Staphs Usually occurs in cattle as a result of traumatic penetration of the pericardial sac with a sharp metallic object or wire. This is Traumatic reticulo-peritonitis Death usually occurs before organisation and a constrictive pericarditis can become apparent.
Sequalae of pericarditis:
- Resolution with no further clinical significance.
- Adhesion: organisation of fibrin. May lead to a bread and butter appearance.
- Constriction: gradual cardiac tamponade will occur.
Pages in category "Pericardial Pathology"
The following 10 pages are in this category, out of 10 total.