What is the recommended management for multiple renal cysts, including simple cysts and autosomal dominant polycystic kidney disease?

Treatment of Multiple Renal Cysts

The management of multiple renal cysts depends critically on whether they represent simple cysts (which require no treatment in most cases) or autosomal dominant polycystic kidney disease (ADPKD), which demands blood pressure control, risk stratification, and consideration of disease-modifying therapy in high-risk patients. 1

Initial Diagnostic Approach

Multiple renal cysts in childhood or young adults are highly suggestive of ADPKD or another hereditary cystic nephropathy and require comprehensive clinical work-up. 2 This evaluation must include:

• Three-generation family history documenting kidney disease, dialysis, transplantation, cerebral aneurysms, and early cardiovascular death 1
• Parental renal ultrasonography, as this may reveal previously undetected ADPKD in approximately 50% of cases that appear to be de novo 2, 1
• Baseline serum creatinine and eGFR to establish kidney function 1
• Blood pressure measurement, as early-onset hypertension is common and prognostically important 1
• Urinalysis to screen for proteinuria or hematuria 1

Key Diagnostic Distinction

Simple cysts affect approximately 50% of individuals older than 50 years and require no routine surveillance or treatment when asymptomatic. 1 In contrast, cysts in ADPKD do not resolve and progressively increase in number and size over time. 1

Management of Confirmed ADPKD

Blood Pressure Control (Cornerstone Therapy)

Target systolic blood pressure <120 mmHg for patients ≥50 years or with CKD stages 3-5, and 110/75 mmHg for patients 18-49 years with CKD stages 1-2. 1

• Use ACE inhibitors or ARBs as first-line agents 1
• Avoid chronic NSAID use for pain management 1

Risk Stratification

Calculate height-adjusted total kidney volume (htTKV) and apply the Mayo Imaging Classification (classes 1A-1E) to predict the rate of renal function decline. 1, 3 This classification is validated only for PKD1 and PKD2 mutations and stratifies patients into five groups indicating accelerating decline in kidney function. 1, 4

Disease-Modifying Therapy

Tolvaptan should be considered for adults at high risk of rapid progression based on Mayo Imaging Classification and total kidney volume, as it slows eGFR decline by 1.3 mL/min/1.73m²/year. 1 This remains the only FDA-approved disease-modifying agent for ADPKD. 3

Management of Symptomatic Cysts

Pain Management Algorithm

For severe, refractory pain from large cysts despite conservative measures:

1. First-line intervention: Percutaneous cyst aspiration followed by ethanol sclerotherapy (approximately 97% efficacy) 1
2. Second-line intervention: Laparoscopic cyst decortication if aspiration fails 1, 5, 6
3. Reserve nephrectomy for cases of severe, intractable pain when accompanied by advanced kidney disease or end-stage renal failure 1

Important caveat: Pain relief from laparoscopic decortication in ADPKD decreases over time—87.5% pain-free at 6 months, 71.4% at 1 year, 66.7% at 2 years, and only 25% at 3 years. 5 Repeat procedures may be necessary to maintain symptom control. 5

Cyst Infection Management

Initial treatment consists of antimicrobials, with quinolone-based regimens favored. 7 However, treatment failure occurs in approximately 51% of cases (improved from 75% before 2000). 7 Factors associated with treatment failure include:

• Post-renal obstruction 7
• Urolithiasis 7
• Atypical or resistant pathogens 7
• Short duration of antimicrobial treatment 7
• Renal function impairment 7

Pediatric-Specific Considerations

In children with multiple renal cysts and negative family history, comprehensive work-up for cystic kidney diseases is mandatory, including parental ultrasonography. 2, 1

• Ultrasonography is the diagnostic method of choice in children, not MRI (which requires sedation in children <6 years and lacks validated diagnostic criteria for those <15 years) 2, 1
• If ultrasound is normal in an at-risk child, repeat screening at intervals of at least 3 years 2, 1
• A normal ultrasound does not exclude ADPKD in children, as cysts develop gradually and may not be detectable early in milder phenotypes 2, 1

Critical Pitfalls to Avoid

• Do not assume simple cysts in young patients or children—the incidence of simple cysts in children is very low, and multiple cysts strongly suggest hereditary disease 2
• Do not postpone blood pressure control or imaging-based risk stratification in confirmed ADPKD, as early intervention improves long-term kidney survival 1
• Do not rely on family history alone—approximately 50% of ADPKD cases arise de novo 1
• Do not apply Mayo Imaging Classification to non-PKD1/PKD2 variants or use it to detect renal malignancy 4, 8
• Complex cysts with septations, calcifications, internal echoes, or irregularities need further characterization with multiphase CT or contrast-enhanced MRI due to malignancy risk 1, 8