Clinal scenario: Hypertension | UTI | renal scaring | cause
An 11-year-old girl is referred for evaluation of persistent hypertension detected during a school health screening. She has a history of multiple febrile urinary tract infections during infancy and early childhood, requiring several hospital admissions. She has been asymptomatic for the past 4 years. Examination reveals a blood pressure above the 99th percentile for age and height. Urinalysis shows 1+ protein but no hematuria. Serum creatinine is mildly elevated. Renal ultrasonography demonstrates a small, irregularly scarred left kidney with compensatory hypertrophy of the right kidney. A 99mTc-DMSA renal scan confirms multiple cortical scars involving the left kidney.
Which of the following is the most likely underlying diagnosis?
A. Autosomal dominant polycystic kidney disease
B. Chronic pyelonephritis due to reflux nephropathy
C. Focal segmental glomerulosclerosis
D. Renal artery stenosis
E. Xanthogranulomatous pyelonephritis
Correct answer & Explanation :
Correct Answer: B. Chronic pyelonephritis due to reflux nephropathy
Explanation: Reflux nephropathy
Reflux nephropathy is the chronic renal damage caused by vesicoureteral reflux (VUR), particularly when associated with recurrent febrile UTIs during early childhood.
The classical features include:
- History of recurrent febrile UTIs in infancy or childhood.
- Renal cortical scarring, best demonstrated by a DMSA scan (gold standard for detecting renal scars).
- A small, irregularly scarred kidney on ultrasound.
- Hypertension due to activation of the renin-angiotensin system.
- Mild proteinuria and progressive chronic kidney disease in advanced cases.
In older children, reflux nephropathy often presents not with recurrent infections, but with hypertension, proteinuria, or reduced renal function.
Why the other options are incorrect
- A. Autosomal dominant polycystic kidney disease: Characterized by bilaterally enlarged kidneys with multiple cysts, not unilateral cortical scarring.
- C. Focal segmental glomerulosclerosis: Causes nephrotic-range proteinuria and progressive CKD but is not associated with recurrent febrile UTIs or focal cortical scars.
- D. Renal artery stenosis: Can cause severe hypertension but does not produce cortical scars or a history of recurrent childhood UTIs.
- E. Xanthogranulomatous pyelonephritis: A rare chronic destructive infection associated with obstruction and renal calculi, usually presenting with persistent fever, flank pain, and a non-functioning kidney.
Learning Point
Reflux nephropathy should be suspected in any child or adolescent with:
- A history of recurrent febrile UTIs in early childhood,
- Hypertension,
- Mild proteinuria,
- A small irregularly scarred kidney, and
- Cortical scars on DMSA scan.
DMSA scintigraphy is the gold standard for detecting renal cortical scarring, whereas voiding cystourethrography (VCUG) is the gold standard for diagnosing vesicoureteral reflux.
References
- Nelson Textbook of Pediatrics, 22nd Edition
- European Association of Urology (EAU)/European Society for Paediatric Urology (ESPU) Guidelines on Pediatric Urology
- American Academy of Pediatrics guidance on urinary tract infection and vesicoureteral reflux
