Thesis paper To find out the relationship between renal histopathological changes and differential renal function

Congenital ureteropelvic junction obstruction (UPJO) is by far the most common cause of paediatric hydronephrosis (Allen, TD et al. 1973) with an incidence of about 1 in 1200 live births. Narrowing (persistent obstruction) at this junction reduces the flow of urine from kidney and produces retrograde changes in proximal tract which actually threatens the function of kidney.

In most cases a congenital intrinsic lesion responsible for UPJO. Upward transmission of ureteral pressure in an obstructed kidney affect tubular pressure, tubular function, renal blood flow (RBF) and glomerular filtration (GFR) (Heymann & Duckett 1988).

Parenchymal damage by UPJO has been well documented by histological changes (Elder & Stock 1995) which are more severe in cases when differential function is less than 35% (Klahar 1992). Significantly urinary obstruction invariably results in tubular dilatation, glomerulosclerosis (glomerulus reduces), inflammation or glomerular hyalinization, cortical cysts and interstitial inflammation with mononuclear cell infiltrate and peritubular fibrosis, tubular atrophy (Mayor et al. 2000).

Although not absolute, a good correlation may exist between the severity of these histopathological changes and the function remaining in the affected kidneys (Elder 1995). After reaching the diagnosis of UPJO it is the differential renal function (DRF) of the individual kidney which is the most useful information obtained during renography. Normal function of renal unit is assumed if it exhibits more than 40% of total uptake on Diethylenetriamine pentaacetic acid (DTPA) renography. Moderately reduced function is defined as 10-40% of total uptake. Severely reduced function is defined as less than 10% at the total uptake. An important question that needs to be answered in large numbers of children is the potential recoverability of function.

In an asymptomatic infant or child the decision to recommend pyeloplasty usually based on interpretation of renal scan (Elder 1995). Split renal function by DTPA is an important investigation which helps in planning of management and follow-up of patient of hydronephrosis. The aim of this study is to evaluate the relationship between differential radionuclide renography with renal histological changes secondary to UPJO in children. This current study is an attempt to correlate between diuretic DTPA renography and renal cortical histological changes in unilateral UPJO considering opposite kidney functioning normal.