Final answer:
The correct ICD-10-CM coding for a patient with chronic pancreatitis that caused diabetes mellitus and is on insulin would be K85.90, K86.1 for chronic pancreatitis, E08.9 for diabetes due to an underlying condition, and Z79.4 for insulin use.
Step-by-step explanation:
The coding and sequencing for a 42-year-old male admitted for acute exacerbation of his chronic pancreatitis, who has developed diabetes mellitus due to the damaged pancreas and is taking insulin, would be based on the ICD-10-CM (International Classification of Diseases, 10th Revision, Clinical Modification) guidelines.
Given that the patient has chronic pancreatitis and has developed diabetes mellitus as a complication of the pancreatitis, the primary diagnosis would be chronic pancreatitis, and diabetes would be a secondary diagnosis. Chronic pancreatitis is coded as K86.1. Since the diabetes is a consequence of the underlying condition (the pancreatitis), it would be classified as diabetes due to an underlying condition, which is coded as E08.9. And because he is on insulin therapy, the use of insulin would also be coded, which is Z79.4.
Therefore, the correct answer for this case would be B. K85.90, K86.1, E08.9, Z79.4. The sequence starts with chronic pancreatitis (K85.90 and K86.1), followed by the diabetes due to the pancreatitis (E08.9), and finally the insulin use (Z79.4).