ICD-10 Code K51.512 – Left sided colitis with intestinal obstruction (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K51.512 – Left sided colitis with intestinal obstruction
What it is
K51.512 identifies left-sided ulcerative colitis when the inflammation is complicated by intestinal obstruction. Use it for documented disease affecting the descending colon, sigmoid colon, or rectum with obstructive findings.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings include left-sided colitis symptoms plus evidence of bowel narrowing or blockage, such as abdominal distention, pain, vomiting, or reduced stool passage.
When to use this code
Use this code when the provider documents left-sided colitis and also states intestinal obstruction. It is appropriate when the obstruction is part of the same encounter and not a separate diagnosis. Check the chart for the exact anatomic location and whether obstruction is confirmed.
Do not use for
Do not use K51.512 if the record does not confirm obstruction, or if the colitis is limited to another ulcerative colitis site. Check documentation when the chart only mentions abdominal pain, ileus, or suspected blockage.
Coding tip
Code both the colitis location and the obstruction only when the provider clearly links them in the documentation.