A 10-year-old girl has polyuria, polydipsia, nocturia, short stature, and normotensive chronic kidney disease. Urine specific gravity is fixed at 1005 despite overnight water deprivation. Ultrasound shows normal sized to small kidneys with increased echogenicity, and MRI shows cysts at the corticomedullary junction. What is the most likely diagnosis?
- A Autosomal dominant polycystic kidney disease
- B Juvenile nephronophthisis ✓
- C Medullary sponge kidney
- D Vesicoureteral reflux nephropathy
Correct answer: B. Juvenile nephronophthisis
Explanation
Juvenile nephronophthisis is the commonest genetic cause of kidney failure in childhood. It produces impaired urinary concentrating ability with polyuria and polydipsia, growth failure, salt wasting, and normotensive CKD, with corticomedullary cysts on imaging. Autosomal dominant polycystic kidney disease presents later with hypertension and large cystic kidneys, and reflux nephropathy gives cortical scars rather than medullary cysts.
Reference: Nelson Textbook of Pediatrics, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.