Anticoagulant rodenticide intoxication in a dog with pericardial effusion and a heart base mass‐like effect

A 4‐year‐old American Pitbull terrier presented for acute onset of a honking cough, vomiting and anorexia. Thoracic radiographs revealed tracheal narrowing consistent with a mass effect or tracheal collapse. The dog was hospitalised but acutely developed respiratory distress, syncope and pale mucous membranes. Moderate pleural effusion and a heart base mass were noted on echocardiographic examination as well as evidence of cardiac tamponade. Coagulation times were severely prolonged. After additional discussion with the owners, rodenticide exposure was considered possible. The owners elected humane euthanasia. A necropsy revealed gross evidence of intrathoracic haemorrhage and a heart base mass consistent with a haematoma. There was no evidence of neoplasia on histopathological evaluation of the tissues. A final diagnosis of rodenticide intoxication was made. This case report demonstrates the importance of considering anticoagulant rodenticide intoxication in patients with a history of pericardial effusion. It is also important to consider a haematoma as a differential diagnosis when a heart‐associated mass is visualised in patients with pericardial effusion.