Renal duplex doppler ultrasonography in patients with recurrent urinary tract infection

Renal hemodynamics were studied using duplex Doppler ultrasonography in forty (33 females and 7 males; mean age: 12.1 +/- 5.3 years) normotensive patients with recurrent urinary tract infection and with no evidence of obstructive uropathy and age matched control group of 24 healthy children and adolescents. Resistivity index (RI) and pulsatility index (PI) in both arcuate (AA) and interlobar (IA) arteries were significantly higher in patients as compared to controls (P= 0.001, 0.01 respectively). Diastolic/systolic ratio (D/S) at the same levels of renal vasculature (AA and IA) was significantly lower in study patients as compared to their controls (P= 0.01, 0.001 respectively). Moreover, scarred renal units had higher RI and PI values as well as lower D/S ratio as compared to non scarred units (p= 0.01, 0.001, 0.001 respectively).). In conclusion, intra renal vascular resistivity is significantly increased in recurrent UTI patients particularly in those sustaining renal scarring. Further follow up studies are recommended to determine if duplex assessment of intrarenal vasculature could be useful as an ancillary diagnostic and/or prognostic technique in the evaluation and follow up of recurrent UTI.