What are the consequences of not treating Ureteropelvic Junction (UPJ) obstruction?

Risks of Not Treating UPJ Obstruction

Untreated ureteropelvic junction (UPJ) obstruction can lead to progressive deterioration of renal function, recurrent urinary tract infections, stone formation, and permanent kidney damage, requiring prompt intervention to preserve renal function and prevent complications.

Potential Consequences of Untreated UPJ Obstruction

Renal Function Deterioration

• Progressive hydronephrosis (kidney swelling) due to impaired urine flow from the renal pelvis to the ureter 1
• Gradual loss of kidney function that may be irreversible if left untreated for extended periods 2
• Decreased differential renal function on the affected side, which can be monitored with Tc-99m MAG3 renal scans 3

Infection-Related Complications

• Increased risk of recurrent urinary tract infections (UTIs) due to urinary stasis 3
• Development of pyelonephritis (kidney infection)
• Potential for urosepsis, a life-threatening complication requiring emergency intervention 3
• Risk of pyonephrosis (pus-filled kidney) requiring drainage procedures 3

Stone Formation

• Higher incidence of kidney stone formation due to urinary stasis 1
• Stones may further complicate the obstruction and increase infection risk 3
• Stone-related events may require additional interventions beyond addressing the UPJ obstruction 3

Pain and Symptom Progression

• Intermittent or persistent flank pain, particularly after fluid intake (Dietl's crisis) 1
• Nausea and vomiting during pain episodes 1
• Hematuria (blood in urine) 1

Structural Changes

• Permanent thinning of renal parenchyma (kidney tissue)
• Development of renal scarring and fibrosis
• Potential for hypertension due to renal damage

Risk Factors for Rapid Progression

Certain factors increase the risk of rapid deterioration in untreated UPJ obstruction:

• High-grade obstruction (severe hydronephrosis) 3
• Bilateral obstruction (affecting both kidneys) 4
• Solitary kidney with obstruction
• Concomitant urinary tract infections 3
• Presence of kidney stones 3
• Young age at presentation (especially neonates) 4

Monitoring Considerations for Untreated UPJ Obstruction

If immediate intervention is deferred, close monitoring is essential:

• Serial ultrasound examinations to assess progression of hydronephrosis 3
• Diuretic renal scans (preferably Tc-99m MAG3) to evaluate differential renal function 3
• Monitoring for signs of infection or pain
• Surgical intervention should be considered when there is:
  • Decreased renal function (<40% differential function)
  • Deteriorating function (>5% change on consecutive scans)
  • Worsening drainage on serial imaging 3
  • Development of symptoms or complications

Treatment Implications

The American Urological Association guidelines indicate that:

• Open/laparoscopic/robotic surgery may be necessary in cases of anatomic abnormalities like UPJ obstruction, especially when reconstruction is required 3
• Endoscopic procedures have lower success rates (42-90%) but may be appropriate in select cases 2
• Pyeloplasty (open, laparoscopic, or robotic) has high success rates (>90%) and is the standard of care for definitive treatment 2

Important Caveats

• Asymptomatic UPJ obstruction may remain clinically silent until adulthood but can still cause progressive damage 1
• Even mild hydronephrosis should not be dismissed, as it may indicate significant obstruction
• The absence of symptoms does not rule out ongoing kidney damage
• Bilateral UPJ obstruction carries a higher risk of renal failure and requires more urgent intervention 4
• Congenital UPJ obstruction diagnosed in neonates shows marked improvement following early correction 4

In summary, UPJ obstruction should be treated promptly when diagnosed to prevent irreversible renal damage, recurrent infections, stone formation, and other complications that significantly impact morbidity, mortality, and quality of life.