While supplies last! Free 2022 Essentials of Interventional Radiology Coding book with every ICD10monitor webcast order. No code required. Order now >

Ulcerative colitis is an inflammatory bowel disease affecting only the innermost layer of the colon and rectal regions. It typically starts in the rectum and affects a continuous bowel segment.

Ulcerative colitis is reported using codes from Category K51, with the condition classified by the site of the inflammation. One difference between ICD-9-CM and ICD-10-CM is that in ICD-10-CM, codes for ulcerative colitis are combination codes that also identify complications of the disease.

Applicable sites also are somewhat different than they are in ICD-9-CM. For ICD-10-CM, documentation should identify the site as:

  • Inflammatory polyps (K51.4-) – Small, localized areas of inflammation
  • Left-sided colitis (K51.5-) – Also called left hemicolitis, involving the rectum, sigmoid colon and descending colon
  • Pancolitis (K51.0-) – Includes ulcerative (chronic) colitis involving the small intestine and colon (enterocolitis) or the ileum and colon (ileocolitis); also called backwash ileitis or universal colitis
  • Proctitis (K51.2-) – Ulcerative colitis involving only the rectum
  • Rectosigmoiditis (K51.3-) – Ulcerative colitis involving only the rectum and sigmoid colon
  • Other ulcerative colitis (K51.8-) – Other specified site or sites
  • Unspecified colitis (K51.9-) – Site is not specified in the documentation

Complications of ulcerative colitis should be identified as:

  • Abscess
  • Fistula
  • Intestinal obstruction
  • Rectal bleeding
  • Other specified complication
  • Unspecified complication
  • Without complication

Pseudopolypsis/Inflammatory Polyps of Colon

ICD-9-CM Code/Documentation

ICD-10-CM Code/Documentation

556.4 Pseudopolyposis of colon

K51.40 Inflammatory polyps of colon without complications

K51.411 Inflammatory polyps of colon with rectal bleeding

K51.412 Inflammatory polyps of colon with intestinal obstruction

K51.413 Inflammatory polyps of colon with fistula

K51.414 Inflammatory polyps of colon with abscess

K51.418 Inflammatory polyps of colon with other complication

K51.419 Inflammatory polyps of colon with unspecified complications

Coding Example

A 54-year-old Caucasian female presents to her gastroenterologist with a four-day history of abdominal pain and bloating. She is having 4-6 loose stools per day, each containing blood and mucous. PMH is significant for ulcerative colitis diagnosed in college and treated with sulfazine for a few years. On review of her medical history, her last flare was almost 10 years ago and was resolved with cortisone enemas. She was advised to schedule a colonoscopy at that time but did not return until today. She admits to being under considerable stress right now. Temperature is recorded at 100.2, HR 88, RR 12, BP 128/70, Wt. 103. On examination this is a thin, almost emaciated-looking patient, impeccably groomed and appearing somewhat younger than her stated age. Oral mucosa is moist and pink with a few scattered aphthous ulcers noted on the posterior pharynx. Abdomen appears slightly distended, with bowel sounds high-pitched and hyperactive. There is tenderness and guarding with deep palpation on the upper and lower left quadrants. DRE causes marked tenesmus. Informed consent is obtained and the patient is sedated for a colonoscopy without bowel prep. Visual exam is significant for inflammation/ulceration of multiple small areas involving the rectum and descending colon. At the junction of the transverse and descending colon is a large pseudopolyp causing significant obstruction of the bowel lumen. This is removed without difficulty and sent for pathology. The patient tolerated the procedure well, and after adequate recovery she is discharged home with a prescription for Azathioprine orally and cortisone enemas. RTC is scheduled a week later for recheck.


Chronic ulcerative colitis with large pseudopolyp causing obstruction at junction of transverse and descending colon.

ICD-10-CM diagnosis code:

K51.412 Inflammatory polyps of colon with intestinal obstruction

ICD-10-CM coding notes:

In the alphabetic index under colitis, ulcerative, pseudopolyp there is a note to see polyps, colon, inflammatory. When this reference is checked, the code provided is K51.40, which is reported for uncomplicated inflammatory polyps. However, the inflammatory polyps are complicated by intestinal obstruction, so code K51.412 is reported.

About the Author

Lauri Gray, RHIT, CPC, has worked in the health information management field for 30 years. She began her career as a health records supervisor in a multi-specialty clinic. Following that she worked in the managed care industry as a contracting and coding specialist for a major HMO. Most recently she has worked as a clinical technical editor of coding and reimbursement print and electronic products. She has also taught medical coding at the College of Eastern Utah. Areas of expertise include: ICD-10-CM, ICD-10-PCS, ICD-9-CM diagnosis and procedure coding, physician coding and reimbursement, claims adjudication processes, third-party reimbursement, RBRVS and fee schedule development. She is a member of the American Academy of Professional Coders (AAPC) and the American Health Information Management Association (AHIMA).

Contact the Author


To comment on this article please go to editor@icd10monitor.com


You May Also Like

Leave a Reply

Your Name(Required)
Your Email(Required)