Dog with idiopathic hypereosinophilic syndrome and aortic blood clot

Abstract

OBJECTIVE: To describe clinically significant thromboembolism as the result of idiopathic hypereosinophilic syndrome (HES) in a dog. CASE SUMMARY: A 3-year-old neutered female Boxer was evaluated for 2-week history of progressive respiratory difficulty and hemoptysis. A brief thoracic ultrasound performed shortly after presentation identified a presumed thrombus within the left atrium. Initial blood work revealed a marked eosinophilia 6.8 × 10/L (6.8 × 10/μL; reference interval, 0.1-2.1 × 10/L [0.1-2.1 × 10/μL]) and evidence of organ dysfunction. Within 24 hours of admission the patient developed acute paraparesis with absent femoral pulses and was euthanized. Necropsy findings included marked infiltration of multiple organs with large numbers of histologically normal eosinophils and numerous thrombi including a large aortic thrombus. This combination of findings resulted in a final diagnosis of HES with associated thromboembolism. NEW OR UNIQUE INFORMATION PROVIDED: Thromboembolism occurs relatively commonly in people with HES. While there are a few case reports of HES in the veterinary literature, this is the first to describe thromboembolism as a manifestation of this disease in a canine patient.