Dynamic chronic rectal obstruction causing a severe colonic dilatation in a cat

CASE SUMMARY A 5-year-old male neutered domestic shorthair cat was presented to our referral centre with a 13 month history of chronic tenesmus due to malunion of the right caudal iliac body. Constipation and pelvic canal stenosis were initially addressed by the referring veterinarian with a right femoral head and neck excision and a right acetabulectomy without observable clinical improvement. At admission, abdominal radiographs revealed severe colonic distension and a narrowed pelvic canal caused by the right proximal femur. Rectal examination and colonography revealed a dynamic compression of the rectum, which worsened with femoral abduction and improved with femoral adduction. A right hindlimb amputation was performed to relieve the obstruction. The cat defaecated 2 days postoperatively and was discharged uneventfully. Neither faecal tenesmus nor dyschaezia were observed over the following 10 months. RELEVANCE AND NOVEL INFORMATION The dynamic nature of the rectal obstruction most likely prevented the development of an irreversible colonic dilatation leading to a megacolon. This is the first report describing a chronic dynamic rectal compression, which was successfully managed with a right hindlimb amputation without the need for subtotal colectomy.