| K51811 | Other ulcerative colitis with rectal bleeding |
| K51812 | Other ulcerative colitis with intestinal obstruction |
| K51813 | Other ulcerative colitis with fistula |
| K51814 | Other ulcerative colitis with abscess |
| K51818 | Other ulcerative colitis with other complication |
| K51819 | Other ulcerative colitis with unspecified complications |
| K519 | Ulcerative colitis, unspecified |
| K5190 | Ulcerative colitis, unspecified, without complications |
| K5191 | Ulcerative colitis, unspecified, with complications |
| K51911 | Ulcerative colitis, unspecified with rectal bleeding |
| K51912 | Ulcerative colitis, unspecified with intestinal obstruction |
| K51913 | Ulcerative colitis, unspecified with fistula |
| K51914 | Ulcerative colitis, unspecified with abscess |
| K51918 | Ulcerative colitis, unspecified with other complication |
| K51919 | Ulcerative colitis, unspecified with unspecified complications |
| K52 | Other and unspecified noninfective gastroenteritis and colitis |
| K520 | Gastroenteritis and colitis due to radiation |
| K521 | Toxic gastroenteritis and colitis |
| K522 | Allergic and dietetic gastroenteritis and colitis |
| K5221 | Food protein-induced enterocolitis syndrome |
| K5222 | Food protein-induced enteropathy |
| K5229 | Other allergic and dietetic gastroenteritis and colitis |
| K523 | Indeterminate colitis |
| K528 | Other specified noninfective gastroenteritis and colitis |
| K5281 | Eosinophilic gastritis or gastroenteritis |
| K5282 | Eosinophilic colitis |
| K5283 | Microscopic colitis |
| K52831 | Collagenous colitis |
| K52832 | Lymphocytic colitis |
| K52838 | Other microscopic colitis |
| K52839 | Microscopic colitis, unspecified |
| K5289 | Other specified noninfective gastroenteritis and colitis |
| K529 | Noninfective gastroenteritis and colitis, unspecified |
| K55 | Vascular disorders of intestine |
| K550 | Acute vascular disorders of intestine |
| K5501 | Acute (reversible) ischemia of small intestine |
| K55011 | Focal (segmental) acute (reversible) ischemia of small intestine |
| K55012 | Diffuse acute (reversible) ischemia of small intestine |
| K55019 | Acute (reversible) ischemia of small intestine, extent unspecified |
| K5502 | Acute infarction of small intestine |
| K55021 | Focal (segmental) acute infarction of small intestine |
| K55022 | Diffuse acute infarction of small intestine |
| K55029 | Acute infarction of small intestine, extent unspecified |
| K5503 | Acute (reversible) ischemia of large intestine |
| K55031 | Focal (segmental) acute (reversible) ischemia of large intestine |
| K55032 | Diffuse acute (reversible) ischemia of large intestine |
| K55039 | Acute (reversible) ischemia of large intestine, extent unspecified |
| K5504 | Acute infarction of large intestine |
| K55041 | Focal (segmental) acute infarction of large intestine |
| K55042 | Diffuse acute infarction of large intestine |