Ulcerative Colitis ICD-10-CM codes

The fourth character of K51 records the extent of disease: K51.0- ulcerative pancolitis, K51.2- ulcerative proctitis, K51.3- ulcerative rectosigmoiditis, K51.4- inflammatory polyps of colon, K51.5- left-sided colitis, K51.8- other ulcerative colitis, and K51.9- unspecified. Ulcerative colitis with no extent documented is K51.90 when uncomplicated.

The fifth and sixth characters follow the same pattern as Crohn's disease: 0 without complications, or 1 with complications and a sixth character of 1 rectal bleeding, 2 intestinal obstruction, 3 fistula, 4 abscess, 8 other complication, or 9 unspecified complication. Pancolitis with rectal bleeding is K51.011. A flare with bleeding should be coded with the bleeding complication rather than adding K92.1 or K62.5.

Toxic megacolon (K59.31) is reported in addition when it complicates ulcerative colitis. After colectomy with ileal pouch, pouchitis is K91.850. When the provider cannot distinguish ulcerative colitis from Crohn's disease, indeterminate colitis is K52.3. As with K50, add codes for associated anal fistula (K60.3-) and manifestations such as pyoderma gangrenosum.