A 48-year-old woman is evaluated for postcoital bleeding and vaginal discharge. Pelvic examination shows a friable mass at the cervix that bleeds easily on touch. Cervical biopsy confirms invasive squamous cell cancer confined to the cervix and uterus. Lymph node metastases are not seen. A radical hysterectomy is performed during which the right ureter is accidentally injured but then repaired. Imaging studies performed after the surgery show a partial obstruction of the right ureter with mild dilation of the proximal collecting system. Which of the following changes are most likely to be seen in the right kidney?

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11ec160b_3cf4_f351_9249_abb45b0bca62_MD0001_00 The glomerular filtration rate (GFR) depends on the interplay of hydrostatic and oncotic pressures in the glomerular capillaries and Bowman's space. The GFR increases with higher glomerular hydrostatic pressure and decreases with increasing Bowman's capsule hydrostatic pressure or higher glomerular capillary oncotic pressure. Acute ureteral obstruction increases hydrostatic pressure proximal to the constriction. This pressure rise is transmitted back to the Bowman's space, resulting in decreased GFR. The filtration fraction (FF) is the portion of the renal plasma flow (RPF) that is filtered from the glomerular capillaries into Bowman's space (ie, the GFR:RPF ratio). With acute ureteral obstruction (first 12 hours), the RPF may transiently increase; however, with time, efferent arteriolar constriction (in response to reduced GFR) will decrease RPF. Even at later stages, though, the GFR remains depressed to a greater extent than the RPF, resulting in reduced FF. Educational objective: Acute ureteral constriction or obstruction decreases the glomerular filtration rate and filtration fraction. __________ References: Renal hemodynamics in acute unilateral ureteral obstruction: contribution of endothelium-derived relaxing factor. (http://www.ncbi.nlm.nih.gov/pubmed/7752393)

A 48-Year-Old Woman Is Evaluated for Postcoital Bleeding and Vaginal