In extreme feline constipation cases, surgery is required to remove the hairball or other intestinal blockage because untreated constipation can cause a condition called megacolon in which the muscular walls of the colon stretch and weaken. (vetinfo.com)
Long term feline constipation can lead to a serious bowel condition known as megacolon. (cat-lovers-only.com)
Cats with megacolon often have bouts of diarrhea and vomiting as well as constipation that looks quite similar to IBD. (2ndchance.info)