Pericardial effusion associated with ehrlichiosis in a dog

Abstract

This report describes a rare manifestation of canine ehrlichiosis presenting with pericardial effusion, emphasizing the clinical, diagnostic, and therapeutic aspects relevant to case management. A 7-month-old dog presented apathy, anorexia, and progressive lethargy, and was found to have anemia and marked thrombocytopenia. Physical examination revealed muffled heart sounds and weak femoral pulses. Hematological analysis confirmed non-regenerative anemia and severe thrombocytopenia, while serological and molecular testing supported infection with Ehrlichia canis. Thoracic imaging and echocardiography demonstrated a substantial pericardial effusion causing hemodynamic compromise, which necessitated immediate pericardiocentesis. Cytological evaluation of the pericardial fluid excluded neoplastic and purulent etiologies, reinforcing suspicion of an inflammatory origin secondary to tick-borne disease. The dog was treated with doxycycline, prednisolone, dipyrone, furosemide, and
imidocarb dipropionate (Imizol®), resulting in progressive clinical improvement, normalization of hematological parameters, and complete resolution of the effusion on follow-up imaging. This case highlights that, although uncommon, cardiac involvement may occur as a complication of canine ehrlichiosis. Prompt recognition of this association, combined with a multidisciplinary therapeutic strategy, is crucial to preventing fatal outcomes and ensuring recovery in complex presentations involving cardiovascular compromise.