Other secondary chronic gout, left knee, with tophus (tophi)

This code signifies a chronic form of gout affecting the left knee, which has developed as a consequence of another underlying condition. The presence of tophi, which are deposits of uric acid crystals, indicates advanced or long-standing disease. This is distinct from acute gout flares or primary gout.

Apply this code when documentation specifies chronic gout in the left knee that is secondary to another disease process, and explicitly mentions the presence of tophi. Supporting documentation should clearly differentiate it from primary gout and confirm the chronic nature and laterality.

• Ensure documentation specifies "secondary" gout and identifies the underlying cause if known, as this may require an additional code.
• Verify the laterality (left knee) and the presence of tophi are clearly stated in the physician's notes.
• Distinguish from M1A.4620 (unspecified tophus) or M1A.4629 (without tophus) for the left knee.