Chronic obstructive pyelonephritis

This code represents a persistent or recurrent bacterial infection of the kidney and renal pelvis, leading to chronic inflammation and potential scarring. It indicates a long-standing inflammatory process within the kidney parenchyma and collecting system due to bacterial invasion.

Use this code when documentation specifies a diagnosis of chronic pyelonephritis that is explicitly described as obstructive. This typically involves evidence of a long-term infectious process in the kidney, often with associated hydronephrosis or other signs of urinary tract obstruction.

• Ensure documentation clearly distinguishes between acute and chronic pyelonephritis.
• Verify that the obstruction is the cause of the pyelonephritis, not just a co-occurring condition, to avoid confusion with obstructive uropathy.
• Do not code with N20.9 (calculous pyelonephritis) or codes from category N13.- (obstructive uropathy) as per the Excludes1 note.