Reiter's disease, multiple sites

This code represents Reiter's disease, also known as reactive arthritis, affecting multiple anatomical sites. It is a form of inflammatory arthritis that develops in response to an infection elsewhere in the body, typically genitourinary or gastrointestinal, and is characterized by a classic triad of arthritis, urethritis, and conjunctivitis, though not all components may be present.

Use this code when documentation specifies a diagnosis of Reiter's disease (reactive arthritis) with involvement of more than one joint or other affected sites (e.g., eyes, genitourinary tract, skin). The physician's diagnostic statement must clearly indicate "Reiter's disease" or "reactive arthritis" and specify "multiple sites" or list multiple affected areas.

• Ensure the documentation explicitly states "multiple sites" or lists at least two distinct anatomical areas affected by Reiter's disease.
• Do not use this code if only a single site is documented; instead, refer to codes for Reiter's disease of specific sites (e.g., M02.31- for shoulder, M02.34- for hand).
• Code any underlying infection (e.g., Chlamydia, Salmonella) separately as an additional diagnosis.