2016 Volume 29 Issue 2 Pages 130-136
With the diagnosis of upper UTI, a radiographic workup is needed to identify which patients are susceptible to renal damage. However, there is incomplete agreement as to whether the emphasis should be on the presence of scarring versus the presence of vesicoureteral reflux (VUR). Historically, the study most commonly used to detect high risk patients was a voiding cystourethrography (VCUG). Collectively, this is now referred to as the bottom-up approach. This method relies on VCUG to identify lower urinary tract abnormalities and VUR. Patients diagnosed with VUR may undergo a 99mTc-DMSA renal scan at a later date to assess scarring. Alternatively, the top-down approach targets the kidney with a 99mTc-DMSA renal scan to diagnose acute renal parenchymal involvement at the time of the upper UTI. Patients with photon defects are subsequently referred for a VCUG to assess VUR in addition to a late 99mTc-DMSA renal scan (6 months) to assess for permanent scarring. As each strategy carries advantages and disadvantages, it is difficult to declare the winner. Meanwhile, new approaches to diagnose renal scarring without invasive procedures, such as magnetic resonance urography or novel biomarkers are under investigation. They may help to clarify the interplay between VUR, renal scarring, and bladder and bowel dysfunction in the future.
