Most children with an isolated multicystic dysplastic kidney (MCDK) will:

• A. Increase risk for systemic hypertension
• B. Maintain normal renal function due to hypertrophy of the contralateral kidney
• C. Require surgical removal of the affected kidney
• D. Progressive renal failure despite contralateral hypertrophy

Answer: (B)

When one kidney is isolatedly multicystic and nonfunctional, the opposite kidney often grows larger to take over the workload. This compensatory hypertrophy boosts its filtration capacity so overall kidney function remains normal. That’s why most children with an isolated unilateral MCDK maintain normal renal function and blood pressure, even though one kidney is dysplastic. Because the healthy kidney handles the job, surgical removal of the affected kidney isn’t routinely needed; it’s considered only if complications arise. Progressive renal failure is unlikely in this scenario since the remaining kidney adapts to meet the body's needs.