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.