ICD-10 Code K51.319 – Ulcerative (chronic) rectosigmoiditis with unspecified complications (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K51.319 – Ulcerative (chronic) rectosigmoiditis with unspecified complications
What it is
K51.319 identifies chronic ulcerative colitis limited to the rectosigmoid area, with a complication that is not further specified. Use it when documentation confirms rectosigmoid involvement and an unspecified complication.
Clinical signs
Typical findings include chronic inflammatory disease of the rectum and sigmoid colon with symptoms such as rectal bleeding, urgency, diarrhea, or abdominal discomfort. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents ulcerative rectosigmoiditis and also notes a complication, but does not name the complication clearly enough for a more specific code. It also fits when the record states chronic disease with unspecified complication. Check documentation if the complication is described elsewhere in the chart.
Do not use for
Do not use it for ulcerative colitis without rectosigmoid involvement, or when the complication is specified and a more exact code is available. Do not assign it if the record does not support chronic ulcerative disease.
Coding tip
Query for the exact complication and disease extent before defaulting to an unspecified code.