In an 11-month male Friesian calf an increase in heart size was noticed, when the pericardium was opened an abundant fibrino-hemorrhagic exudate was observed, along with cave formation, adhesions to the epicardium and nodular structures.

Histologically a fibrinous exudate was observed in reorganization, with formation of cubic epithelium coated pseudopapillae (reactive mesothelium). A moderate lymphoplasmocytic infiltrate was present along with macrophages and a few neutrophils. The lesion was classified as a chronic fibrinous pericarditis.

Although the type of lesion indicated a bacterial etiology, on microbiological culture no bacteria could be isolated associated with this type of pathology. This is most likely due to the chronicity of the lesion.

One possible explanation for this type of lesion would be a traumatic pericarditis (caused by the presence of a sharp object in the reticulum).

Fibrinous pericarditis. Picture of the sectioned Pericardium.

Fibrinous pericarditis. Picture of the sectioned Pericardium.

Detail of the inflammatory exudate.

Detail of the inflammatory exudate.