Final answer:
The patient should be coded as a) K50.011 because it specifically indicates Crohn's disease of the large intestine with rectal bleeding. Options K92.1, D63.0, and K51.911 are not accurate for this patient's condition.
Step-by-step explanation:
The primary concern in the case of a patient with chronic rectal bleeding and a diagnosis of Crohn's disease of the descending colon, accompanied by chronic blood-loss anemia, is to establish the correct medical coding for the diagnosis. The medical codes provided as options are a) K50.011, b) K92.1, c) D63.0, d) K51.911. Considering the specifics of the case, the appropriate code for Crohn's disease involving the large intestine is K50.011. Code K92.1 represents non-specific rectal bleeding, which is not specific enough for this scenario. Code D63.0 corresponds to anemia in chronic diseases classified elsewhere, which would be secondary to this patient's primary diagnosis. Code K51.911 pertains to ulcerative colitis, which is a different type of inflammatory bowel disease not applicable to this patient. Therefore, option a) K50.011 is the correct answer as it specifically identifies Crohn's disease of the large intestine with rectal bleeding.