Case Description—An 8-week-old female domestic shorthair cat was treated for patent ductus arteriosus (PDA) with surgical ligation. Seven weeks postoperatively, the cat was evaluated because of increased upper respiratory noise, inspiratory stridor, wheezing, and episodes of intermittent open-mouth breathing that had developed 1 week following the surgical ligation.
Clinical Findings—The cat was sedated, and examination of the larynx revealed left-sided laryngeal paralysis.
Treatment and Outcome—At the time left-sided laryngeal paralysis was diagnosed, the clinical signs of laryngeal dysfunction were not considered severe enough to warrant surgical intervention. No treatment was administered, and the owner monitored the cat for respiratory distress and worsening of clinical signs for an additional 5 months. During those 5 months, the clinical signs improved but persisted. Seven months after PDA ligation, the cat was again sedated and the larynx examined. The examination revealed persistent left arytenoid dysfunction, which was believed to be the result of permanent damage to the recurrent laryngeal nerve that was sustained during the surgical ligation of the PDA. The owner was counseled about surgical and medical treatment options for laryngeal paralysis but elected to forego treatment at that time.
Clinical Relevance—Unilateral laryngeal paralysis caused by iatrogenic damage to the recurrent laryngeal nerve is a potential complication subsequent to surgical ligation of a PDA. The frequency of iatrogenically induced laryngeal paralysis is likely underestimated in small animal patients. Laryngoscopy should be performed in any small animal with a history of PDA attenuation and clinical signs of respiratory tract disease.
OBJECTIVE To evaluate colonoscopic and histologic features of rectal masses in dogs.
DESIGN Retrospective case series.
ANIMALS 82 client-owned dogs with rectal masses that underwent colonoscopy.
PROCEDURES Medical records of dogs with rectal masses that underwent colonoscopy were reviewed. History, signalment, clinical signs, results of physical examination, diagnostic imaging findings, and results of colonoscopy (including complications) were recorded. When available, tissue samples obtained during colonoscopy and by means of surgical biopsy were reviewed by a single board-certified pathologist. Histologic features and tumor grade (when applicable) of tissue samples obtained during colonoscopy versus surgical biopsy were compared.
RESULTS Multiple rectal masses were observed during colonoscopy in 6 of the 82 dogs, but no lesions were visualized orad to the colorectal junction. Results of histologic evaluation of surgical biopsy specimens were consistent with a diagnosis of epithelial neoplasia in 58 of 64 dogs, of which 71% were classified as benign adenoma or polyp and 29% were classified as adenocarcinoma in situ or adenocarcinoma. Complications of colonoscopy occurred in 3 of 82 dogs but were considered minor. A discrepancy in diagnosis occurred in 5 of 16 dogs for which both colonoscopic and surgical biopsy samples were available for histologic review.
CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that multiple rectal masses are uncommon in dogs, and secondary lesions orad to the colorectal junction were not found in this study. Colonoscopy was associated with few complications, but the need for colonoscopic assessment of the entire colon in this patient population may merit reevaluation.