ICD-10 Code K51.518 – Left sided colitis with other complication (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K51.518 – Left sided colitis with other complication
What it is
K51.518 identifies left-sided colitis, a form of ulcerative colitis affecting the descending colon and sometimes the rectum. The “other complication” wording means the record documents an additional complication, but not one named by a more specific code.
Clinical signs
Typical findings include chronic diarrhea, rectal bleeding, abdominal pain, and urgency. Clinical features vary; refer to documentation, especially when the chart notes a complication such as obstruction, perforation, or another specified problem.
When to use this code
Use this code when the provider clearly documents left-sided colitis and also documents a complication that is not separately classified by a more specific ulcerative colitis code. Confirm that the complication is part of the current diagnosis, not just a historical note. If the record only says “left-sided colitis” without a complication, check documentation for the correct, more specific code.
Do not use for
Do not use it for ulcerative colitis without a documented complication, or when the disease location is different from left-sided involvement. Do not assign it if the complication is unspecified or better coded elsewhere; check documentation.
Coding tip
Match the code to both the colitis location and the exact complication wording in the note.