Pericardial effusion represents an important clinical entity in a variety of settings. It is routinely seen in the exam room of general practitioners and often at referral institutions. It has a variable constellation of signs, and dogs may present for signs lasting from minutes to months, episodic or continuous. It typically arises secondary to cardiac tumors, though idiopathic pericardial effusion is also a common cause. Mesothelioma is the culprit in a minority of cases, though it can mimic the other etiologies and should not be ruled out without rigorous post-mortem investigation.
This case of mesothelioma-induced pericardial effusion with secondary cardiac tamponade demonstrates the classical presentation and clinical course of most pericardial effusions, as well as the importance of maintaining mesothelioma on a differential diagnosis list until post-mortem. Due to extensive overlap that exists between the various etiologies, this report covers the general clinical approach to canine pericardial effusion.