N11.1 Chronic obstructive pyelonephritis

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applicable to

• Pyelonephritis (chronic) associated with anomaly of pelviureteric junction
• Pyelonephritis (chronic) associated with anomaly of pyeloureteric junction
• Pyelonephritis (chronic) associated with crossing of vessel
• Pyelonephritis (chronic) associated with kinking of ureter
• Pyelonephritis (chronic) associated with obstruction of ureter
• Pyelonephritis (chronic) associated with stricture of pelviureteric junction
• Pyelonephritis (chronic) associated with stricture of ureter

Excludes1 (never code together)

• calculous pyelonephritis (N20.9)
• obstructive uropathy (N13.-)

Applies from N11 Chronic tubulo-interstitial nephritis

Includes

• chronic infectious interstitial nephritis
• chronic pyelitis
• chronic pyelonephritis

Use additional code

• code (B95-B97), to identify infectious agent.

MS-DRG index

Defines the logic of DRG(s) 693-694 in MDC 11.

Approximate ICD-9-CM (GEMs)

• 590.01 Chronic pyelonephritis with lesion of renal medullary necrosis (approximate)
• 593.3 Stricture or kinking of ureter (approximate)
• 593.4 Other ureteric obstruction (approximate)

Code annotations containing back-references to N11.1

Back-references to N11.1

• Type 2 Excludes: N13 Obstructive and reflux uropathy ("obstructive pyelonephritis (N11.1)")

Back-references to N11

• Type 1 Excludes: N03 Chronic nephritic syndrome ("chronic tubulo-interstitial nephritis (N11.-)")

Diagnosis Index entries for N11.1

• Kink, kinking › ureter (pelvic junction) › with › pyelonephritis (chronic)
• Nephritis, nephritic (albuminuric) (azotemic) (congenital) (disseminated) (epithelial) (familial) (focal) (granulomatous) (hemorrhagic) (infantile) (nonsuppurative, excretory) (uremic) › tubulo-interstitial (in) › chronic (infectious) › obstructive
• Obstruction, obstructed, obstructive › pyelonephritis (chronic)
• Obstruction, obstructed, obstructive › ureter (functional) (pelvic junction) NEC › with › pyelonephritis (chronic)
• Pyelonephritis › chronic › associated with ureteral obstruction or stricture
• Pyelonephritis › chronic › obstructive
• Pyelonephritis › in (due to) › obstruction
• Pyelonephrosis (obstructive)
• Stricture › ureter (postoperative) › with › pyelonephritis (chronic)

Nearby codes

• N11 Chronic tubulo-interstitial nephritis
• N11.0 Nonobstructive reflux-associated chronic pyelonephritis
• N11.1 Chronic obstructive pyelonephritis (this code)
• N11.8 Other chronic tubulo-interstitial nephritis
• N11.9 Chronic tubulo-interstitial nephritis, unspecified