Clinical scenario: Failure to thrive | Hypertension | Enlarged kidneys
A 3-month-old infant is admitted with poor feeding, failure to thrive, and respiratory distress. Examination reveals severe hypertension and markedly enlarged bilateral kidneys. Liver function tests are normal, but abdominal ultrasound shows bilaterally enlarged echogenic kidneys with poor corticomedullary differentiation. There is no family history of kidney disease.
What is the most likely diagnosis?
A. Autosomal dominant PKD
B. Autosomal recessive PKD
C. Multicystic dysplastic kidney
D. Nephronophthisis
E. Obstructive uropathy
Correct answer & Explanation:
Correct answer: B. Autosomal recessive PKD
Explanation:
This infant has autosomal recessive polycystic kidney disease (ARPKD), characterized by:
- Presentation in infancy or early childhood
- Bilaterally enlarged echogenic kidneys (rather than discrete large cysts)
- Severe hypertension
- Renal insufficiency
- Later development of congenital hepatic fibrosis and portal hypertension
Why the other options are incorrect:
- A. ADPKD – Usually presents in adolescence or adulthood with a positive family history.
- C. Multicystic dysplastic kidney – Typically unilateral with a non-functioning kidney.
- D. Nephronophthisis – Causes small or normal-sized kidneys and presents with polyuria rather than massive nephromegaly.
- E. Obstructive uropathy – Imaging usually demonstrates hydronephrosis rather than diffusely echogenic enlarged kidneys.
Key point:
Infant + enlarged echogenic kidneys + severe hypertension = ARPKD until proven otherwise.
