What is the treatment for kidney scarring?

Treatment for Kidney Scarring

The most effective approach to managing kidney scarring is early and aggressive antibiotic treatment of urinary tract infections (UTIs) to prevent the development of new scars, combined with monitoring for recurrent infections and appropriate imaging to detect anatomical abnormalities that may require further intervention. 1

Understanding Kidney Scarring

• Kidney scarring (renal scarring) is a long-term sequela of urinary tract infections, particularly pyelonephritis, that can lead to hypertension and chronic renal failure 1
• Approximately 15% of children show evidence of renal scarring after the first episode of UTI 1
• Contrary to earlier beliefs, the long-term risk of end-stage renal disease from UTI-related scarring is lower than previously thought, accounting for only 3.5% of cases according to North American data 1
• Renal scarring risk increases with the number of UTI recurrences - having 2 UTIs increases scarring odds by a factor of 12, and 3 UTIs by a factor of 14 1

Prevention of New Scarring

Early Detection and Treatment of UTIs

• Prompt diagnosis and treatment of UTIs is the cornerstone of preventing kidney scarring 1, 2
• Parents/guardians should seek medical evaluation within 48 hours of febrile illness in children with history of UTI 1
• Urine specimens should be obtained at the onset of subsequent febrile illnesses in children with prior UTI to enable prompt diagnosis and treatment 1
• Early antibiotic treatment stops bacterial multiplication and prevents the inflammatory response that leads to tissue damage and scar formation 2

Antibiotic Therapy

• For uncomplicated pyelonephritis, fluoroquinolones and cephalosporins are recommended for empirical oral treatment 3, 4
• Hospitalized patients should initially receive intravenous antimicrobial therapy 3
• Standard treatment duration is 7-14 days 3
• When treatment is delayed, antibiotics alone may eliminate bacteria but not prevent scar formation 5

Anti-inflammatory Therapy

• Research suggests that adding anti-inflammatory agents (such as prednisolone) to antibiotic therapy may help prevent renal scarring when antibiotic treatment is delayed 5
• The inflammatory response, particularly from polymorphonuclear leukocytes, appears responsible for permanent renal tissue damage 2

Monitoring and Follow-up

Imaging

• Ultrasonography of the kidneys and bladder should be performed after UTI to detect anatomical abnormalities requiring further evaluation 1
• DMSA renal scan may be considered for follow-up to detect new renal scarring, especially after febrile UTI or when renal ultrasound is abnormal 1, 6
• Follow-up DMSA examination should not be performed until at least 6 months after acute infection to allow reversible lesions to disappear 6
• Voiding cystourethrography (VCUG) is indicated if ultrasound reveals hydronephrosis, scarring, or other findings suggesting high-grade vesicoureteral reflux (VUR) or obstructive uropathy 1

High-Risk Populations

• Patients with bilateral scarring require closer monitoring due to higher risk of decreased renal function 7
• Even patients with unilateral scarring are at risk for serious long-term complications including hypertension 7
• Other high-risk groups include those with diabetes, anatomical abnormalities of the urinary tract, VUR, renal obstruction, and immunosuppressed patients 8

Management of Established Scarring

• Long-term follow-up monitoring should be maintained for patients with renal scarring 1, 7
• Patients with post-infectious renal scars should be followed as high-risk patients with treatment continuity between pediatricians, nephrologists, and when required, obstetricians 7
• Monitor for development of hypertension, particularly in patients with extensive scarring 7
• Assess renal function periodically as filtration fraction may be higher in patients with extensive renal scarring, indicating glomerular hyperfiltration by remnant glomeruli 7

Special Considerations

• The relationship between childhood UTIs and reduced renal function in adults is established but not well characterized quantitatively 1
• Continuous antibiotic prophylaxis (CAP) has been used historically to prevent UTIs in children with urinary tract dilation, but studies have not demonstrated a reduction in renal scarring with this approach 1
• The role of vesicoureteral reflux (VUR) in causing renal scarring is incompletely understood; pyelonephritis and progressive renal scarring can occur in the absence of demonstrated VUR 1