Bilateral renal disease with hyperechoic enlarged kidneys, extreme oligohydramnios, and no visible bladder is most consistent with which condition?

• A. Infantile polycystic disease
• B. Multicystic dysplastic kidney
• C. Posterior urethral valve obstruction
• D. Renal agenesis

Answer: (A)

This pattern highlights fetal autosomal recessive polycystic kidney disease (infantile polycystic kidney disease). The kidneys are enlarged and highly echogenic because tiny cysts in the collecting ducts give a bright, uniform appearance. Because these kidneys can’t produce enough urine, amniotic fluid becomes severely decreased (oligohydramnios), which often makes the bladder difficult or impossible to visualize on ultrasound. The combination of bilateral, enlarged, hyperechoic kidneys with extreme oligohydramnios and an absent bladder is classic for this condition.

Other scenarios don’t fit as well. Renal agenesis would show no kidneys at all rather than enlarged kidneys. Posterior urethral valve obstruction can cause obstruction with hydronephrosis, but the bladder is usually visible and often distended, not absent, and the kidneys aren’t characteristically uniformly hyperechoic and enlarged. Multicystic dysplastic kidney is typically unilateral and presents as a nonfunctioning, cystic mass rather than diffuse, diffuse echogenic enlargement of both kidneys.