Reiter's disease, unspecified shoulder

This code describes an inflammatory arthropathy, specifically Reiter's disease (now more commonly referred to as reactive arthritis), affecting an unspecified shoulder. Reactive arthritis is characterized by sterile inflammation of the joints, often triggered by a preceding infection elsewhere in the body, such as gastrointestinal or genitourinary infections. The "unspecified shoulder" indicates that the laterality (left or right) of the affected shoulder is not documented.

Use this code when documentation confirms a diagnosis of Reiter's disease or reactive arthritis, and the patient presents with symptoms localized to the shoulder joint, but the specific side (left or right) is not specified. This code is appropriate when the provider's notes clearly state "Reiter's disease of shoulder" or "reactive arthritis affecting shoulder" without further laterality detail.

• Ensure the documentation explicitly states "unspecified shoulder" or lacks laterality information for the shoulder joint.
• If laterality is specified (e.g., left or right shoulder), use the more specific codes M02.311 (right shoulder) or M02.312 (left shoulder).
• Always look for documentation of the underlying infection that may have triggered the reactive arthritis, as this may require additional coding.