125I-hippuran absorption from the human renal pelvis

Area of Science:

• Nephrology
• Urology
• Nuclear Medicine

Background:

• Pelviureteric junction obstruction can impair renal function.
• Understanding the dynamics of the renal pelvis is crucial for managing obstruction.

Purpose of the Study:

• To investigate the absorption and reflux of 125I-hippuran from the human renal pelvis in patients with pelviureteric junction obstruction.
• To evaluate the impact of intrapelvic pressure, diuresis, and renal function on this reflux.

Main Methods:

• Studied 18 patients with pelviureteric junction obstruction undergoing surgery.
• Measured 125I-hippuran absorption under induced diuresis and constant intrapelvic pressure (30 cm H2O).
• Assessed glomerular filtration rate (GFR) using 51Cr-EDTA and evaluated distal tubular function; monitored contralateral kidney excretion.

Main Results:

• Induced diuresis increased intrapelvic pressure to an average of 31.6 cm H2O.
• Contralateral kidney excretion of the isotope ranged from 1% to 44%, significantly correlating with maximum intrapelvic pressure (r=0.87).
• At constant 30 cm H2O pressure, contralateral excretion ranged from 2% to 26%, likely due to impaired function of the obstructed kidney.

Conclusions:

• Demonstrated significant reflux of small molecules from the renal pelvis in patients with pelviureteric junction obstruction.
• Reflux is demonstrably affected by renal function, intrapelvic pressure, and volume.
• These findings highlight the importance of considering reflux dynamics in the management of pelviureteric junction obstruction.