Megacolon is a severe and painful condition of cats in which the colon loses its ability to contract, causing chronic constipation that is both distressing and difficult to manage.
Megacolon causes significant and distressing welfare compromise. Cats unable to defecate experience pain, abdominal distension, nausea, and in acute obstipation (complete impaction), life-threatening toxaemia. Manual de-obstipation under anaesthesia is required for severe episodes — a welfare-significant procedure that must be repeated in chronic unmanaged cases. Cats with megacolon straining to defecate multiple times daily show clear signs of discomfort and frustration. Subtotal colectomy, though a significant abdominal surgery, typically results in dramatic welfare improvement: most cats defecate within days of surgery with normal or near-normal frequency. Post-operative diarrhoea is common for weeks to months but resolves as the remaining bowel adapts. For refractory medical cases, surgery represents the most welfare-positive management option.