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Renal scarring following reflux and nonreflux pyelonephritis in children: evaluation with
H G Rushton1, M Majd, B Jantausch
1Department of Urology, Children's Hospital, Washington, D.C. 20010.
Insights
Renal scarring in children after pyelonephritis primarily occurs at sites of initial inflammation. Acute kidney inflammation is often reversible, and scarring is not dependent on vesicoureteral reflux.
Area of Science:
- Pediatric Nephrology
- Diagnostic Imaging
Background:
- 99mTechnetium dimercaptosuccinic acid (DMSA) scintigraphy is crucial for diagnosing acute pyelonephritis and renal scarring in children.
- Understanding the progression of renal scarring after acute pyelonephritis is essential for pediatric kidney health.
Purpose of the Study:
- To prospectively evaluate the development of renal scarring after acute pyelonephritis in children.
- To determine the relationship between vesicoureteral reflux and new or progressive renal scarring.
- To investigate factors influencing renal scarring post-pyelonephritis.
Main Methods:
- Prospective evaluation of 33 children with acute pyelonephritis using serial DMSA scans.
- Follow-up DMSA scans were performed 4 to 42 months post-infection to assess renal scarring.
- Analysis included stratification based on the presence of vesicoureteral reflux and underlying bladder/urethral conditions.
Main Results:
- New or progressive scarring developed in 42% of kidneys studied.
- Scarring occurred exclusively at sites of initial acute inflammation identified on the first DMSA scan.
- New scarring was significantly more common in kidneys associated with neuropathic bladder or posterior urethral valves (86%) compared to normal bladders (32%).
- Excluding complex cases, scarring rates were similar with or without vesicoureteral reflux (25% vs. 37%).
Conclusions:
- Acquired renal scarring is localized to areas of previous acute pyelonephritis.
- Acute inflammatory changes in pyelonephritis are largely reversible, with most cases not leading to new scarring.
- The development of renal scarring after acute pyelonephritis is independent of vesicoureteral reflux, particularly in cases with normal bladder function.
Abstract:
99mTechnetium dimercaptosuccinic acid (DMSA) scintigraphy is the imaging modality of choice for the detection of acute pyelonephritis and chronic renal scarring in children. Using the DMSA scan we prospectively evaluated renal scarring after reflux and nonreflux pyelonephritis in children. The study population consisted of 33 patients with acute pyelonephritis documented by a DMSA renal scan at infection. The children were evaluated for renal scarring with a followup DMSA scan 4 to 42 months (mean 10.7 months) after the acute infection. All new scarring on followup DMSA scans occurred at sites corresponding exactly to areas of acute inflammation on the initial DMSA scan. Therefore, only those kidneys with acute changes on the initial scan were subsequently analyzed. Of 38 kidneys new or progressive scarring developed in 16 (42%), including 6 of 15 (40%) with associated vesicoureteral reflux and 10 of 23 (43%) without demonstrable reflux. New renal scarring developed in 6 of the 7 kidneys (86%) associated with a neuropathic bladder or posterior urethral valves. In contrast, new scarring developed in only 10 of 31 kidneys (32%) associated with a normal bladder (p = 0.028). Excluding the kidneys associated with a neuropathic bladder or posterior urethral valves, new renal scarring developed in 3 of 12 (25%) with primary reflux, compared with 7 of 19 (37%) without vesicoureteral reflux. Except for the white blood count and the species of infecting bacteria, no other statistically significant differences could be found between those cases in which scars did or did not develop. We conclude that acquired renal scarring only occurs at sites corresponding to previous areas of acute pyelonephritis, the acute parenchymal inflammatory changes of acute pyelonephritis are reversible and do not lead to new renal scarring in the majority of cases, and once acute pyelonephritis has occurred ultimate renal scarring is independent of the presence or absence of vesicoureteral reflux.