Horse with neck swelling and breathing trouble from lymphosarcoma

Abstract

A 9-year-old, 1494-lb (679-kg) Quarter horse gelding in good body condition was admitted to the Veterinary Teaching Hospital, Western College of Veterinary Medicine (WCVM), University of Saskatchewan, for evaluation and treatment of acute respiratory distress. On a trail ride 26 days before presentation, the gelding had been exposed to a horse with clinical signs of an upper respiratory tract infection. The gelding performed well on the trail ride but, 4 days later, developed a mild swelling in the retropharyngeal area and a slight bilateral mucoid nasal discharge. The gelding was examined at the farm by its primary veterinarian, who made a presumptive diagnosis of strangles. Treatment was initiated using a combination of trimethoprim/sulfamethoxazole (30 mg/kg PO q12h for 1 week) and phenylbutazone (6 mg/kg PO q24h for the first 2 days, followed by 3.5 mg/kg PO q24h for 5 more days). The gelding did not respond satisfactorily to antimicrobial and antiinflammatory therapy. During the following 2 weeks, the retropharyngeal swelling gradually became more pronounced and extended to the upper portion of the neck. Two days before presentation at WCVM, the gelding also developed a dry cough with difficult breathing, and the retropharyngeal and neck swelling extended to the pectoral region and ventral pectoral area extending to the cranial ventral abdomen. Because of progressing clinical signs and poor response to treatment, the horse was referred to WCVM for further evaluation.