Drug-induced chronic gout, unspecified knee, without tophus

This code signifies a chronic inflammatory arthritis affecting an unspecified knee joint, directly caused by medication. The condition is characterized by recurrent episodes of pain, swelling, and tenderness due to uric acid crystal deposition, but without the presence of visible or palpable tophi.

Use this code when documentation clearly indicates chronic gout in a knee joint, explicitly attributed to a drug, and no specific laterality (right or left) is documented. The physician's notes should specify "drug-induced" and confirm the absence of tophaceous deposits.

• Ensure the documentation specifies "drug-induced" to differentiate from primary or secondary gout not caused by medication.
• Verify that no laterality (right or left knee) is documented; otherwise, a more specific code should be used.
• Always code the adverse effect of the drug first, followed by this code to fully capture the clinical picture.