Crohn's Disease ICD-10-CM codes

The fourth character of K50 identifies the site: K50.0- small intestine (including ileitis and Crohn's of the terminal ileum), K50.1- large intestine (Crohn's colitis), K50.8- both small and large intestine (ileocolitis), and K50.9- unspecified. Crohn's disease with no site documented is K50.90 when uncomplicated.

The fifth character is 0 for no complications and 1 for complications, and the sixth character names the complication: 1 rectal bleeding, 2 intestinal obstruction, 3 fistula, 4 abscess, 8 other complication, and 9 unspecified complication. Small bowel Crohn's with obstruction is therefore K50.012. Because the complication is part of the code, a separate code for the bleeding or obstruction is not added. Assign more than one K50 code when the patient has several documented complications.

K50 has use-additional-code instructions for associated anal or rectal fistulas (K60.3- to K60.5-) and for manifestations such as pyoderma gangrenosum (L88). Perianal abscess (K61.0) is reported in addition when documented. Malnutrition (E44.- or E43) and iron deficiency anemia from chronic blood loss (D50.0) are common secondary diagnoses and should be coded when the provider documents them.