Drug-induced chronic gout, left knee, without tophus (tophi)

This code signifies a persistent inflammatory arthritis affecting the left knee, specifically caused by medication, where uric acid crystals have deposited in the joint but without the formation of visible or palpable tophi. The condition is characterized by recurrent attacks of severe pain, swelling, and tenderness in the affected joint due to elevated uric acid levels induced by drug therapy.

Apply this code when documentation clearly indicates chronic gout in the left knee, explicitly attributed to a drug, and the absence of tophaceous deposits. This is appropriate for patients experiencing ongoing or recurrent gout flares in the left knee as a direct consequence of a prescribed medication. The medical record should specify the drug implicated.

• Ensure documentation specifies "chronic" gout and explicitly links it to a drug.
• Verify the affected joint is the "left knee" and that "without tophus (tophi)" is clearly stated.
• Always code the adverse effect of the drug (T36-T50 with a 5th or 6th character of 5) as a secondary diagnosis to identify the causative medication.