Lead-induced chronic gout, unspecified knee, with tophus

This code signifies a chronic inflammatory arthritis caused by elevated lead levels, specifically affecting an unspecified knee joint. The presence of tophi, which are deposits of uric acid crystals, further characterizes this condition. This indicates a long-standing and severe form of lead-induced gout.

Apply this code when documentation confirms a diagnosis of chronic gout directly linked to lead exposure, with evidence of tophaceous deposits in an unspecified knee. Supporting documentation should include laboratory findings indicating elevated lead levels and hyperuricemia, along with clinical notes describing chronic knee pain, inflammation, and the presence of tophi.

• Ensure documentation clearly links the gout to lead exposure; otherwise, a different etiology of gout may be more appropriate.
• Verify the presence of tophi is explicitly stated; if absent, a code without tophi should be used.
• If the specific knee (right or left) is documented, a more specific code from the M1A.16 category should be selected.