Chronic pyelonephritis
Chronic pyelonephritis is the product of recurrent or persistent acute pyelonephritis and results in renal pelvic fibrosis. It generally occurs in patients who have vesicoureteral reflux (VUR) or anatomical abnormalities. Chronic pyelonephritis can be divided into two groups:
- Reflux chronic pyelonephritis (associated with VUR)
- Obstructive chronic pyelonephritis
VUR is present in 30-40% of children with UTIs, and almost all children who have chronic pyelonephritis. It is classified into five grades (1-5) based on the degree of reflux.
Chronic pyelonephritis can lead to end-stage renal disease due to excessive scarring and fibrosis of the kidney parenchyma.
The clinical picture of chronic pyelonephritis is less specific than the acute form, patients may report intermittent fever, tiredness, flank/back pain and loss of tubular function causing polyuria and nocturia.
Vesicoureteral reflux
Grading:
- Grade I - reflux into lower ureter on micturition
- Grade II - reflux into renal pelvis on micturition but absence of ureteral dilation
- Grade III - constant reflux with mild to moderate dilation of the ureter and pelvis
- Grade IV - constant reflux with dilation of the ureter; Grade V - gross dilation and tortuosity of the ureter, pelvis and calyces
Investigation should be via micturating cystography, while renal imaging may be useful i assessing renal function and scarring.
Micturating cystourethrogram in a child: contrast placed in the bladder flows back up both ureters into both renal pelvises and calyces (bilateral vesicoureteral reflux).
Image: “Vesicoureteral-reflux-004” by RadsWiki, CC BY-SA 3.0, via Wikimedia Commons.
Management of grades I and II are managed conservatively, with high fluid intake, regular voiding and increased hygiene. Grades III and IV require surgical correction, with tunneling of the ureter through the bladder wall.