Multicystic Dysplastic Kidney

Abstract

The primary aim in diagnosis and management of multicystic dysplastic kidney (MCDK) is preservation of contralateral renal function.

Secondary aims:

• 1. Diagnosis and management of associated HTN.

• 2. To prevent malignancy.

Summary of evidence for these goals:

Retrospective series variously define subnormal renal function as GFR <80 or 90 mL/min/1.73 m², or <80 % normal for age and gender.

• A prospective registry reported all 76 children followed for 5–10 years had GFR >60 mL/min/1.73 m², with 43 % between 60 and 90 mL/min/1.73 m².

• A retrospective series of 36 children with similar follow-up and a normal contralateral kidney by US reported 12 % had GFR <80 mL/min/1.73 m².

• Analysis of potential hyperfiltration injury in patients with MCDK or unilateral renal agenesis versus normal controls reported that patients had mean GFR less than controls (93 ± 20 vs. 114 ± 14).

Meta-analysis reported contralateral anomalies potentially impacting renal function, including UPJO in 5 %, ureterocele in 1 %, and PUV in 0.4 %.

Contralateral VUR, mostly grades 1–3, occurs in 20 %.

• One study found no difference in serum creatinine for age in patients with versus without contralateral VUR.

• Twelve newborns with MCDK would need VCUG to detect one ureter with grades 3–5 VUR.

• Retrospective studies indicate that >50 % of contralateral VUR resolves by ≤2 years of age.

• No RCT shows benefit of antibiotic prophylaxis versus no therapy to prevent first fUTI in patients with contralateral VUR.

Our review found no evidence that the diagnosis of VUR significantly impacts renal functional outcomes in children with MCDK, suggesting that routine cystography is not necessary.

Systematic literature review reports that the rate of HTN is 5 per 1,000, with insufficient data to state duration of follow-up needed to detect most cases. Two studies with a total of 27 patients report BP normalization in 68 and 100 % after nephrectomy.

Malignancy, including Wilm’s tumor and renal cell carcinoma, has only been published as case reports, with no cohort study reporting tumor development during follow-up.

Our review found no evidence that renography demonstrating no uptake versus uptake alters prognosis or management of MCDK (i.e., impacts risk for HTN or malignancy), so nuclear renal scan should be considered an optional investigation for children with this condition.

Sports-related renal injury was also reviewed to determine potential risk to a solitary functioning kidney, finding the following:

• Injuries resulting in functional loss or nephrectomy are rare.

• Most injuries are reported related to American football, with an incidence of <0.7 %.

• Most injuries occur in children ≥12 years of age.

• No evidence-basis to restrict sports participation in children with a solitary kidney.