Definition of Steroid-Dependent Nephrotic Syndrome
Steroid-dependent nephrotic syndrome (SDNS) is defined as 2 or more relapses during corticosteroid tapering OR 1 relapse within 14 days of corticosteroid cessation. 1
Detailed Diagnostic Criteria
The definition of SDNS is standardized across major international guidelines and represents a specific pattern of disease behavior that distinguishes it from other forms of nephrotic syndrome:
Core Definition
- SDNS occurs when patients experience ≥2 relapses during the steroid taper phase 1
- Alternatively, SDNS is diagnosed when 1 relapse occurs within 14 days after stopping corticosteroids 1
Distinguishing SDNS from Other Patterns
This definition helps differentiate SDNS from other nephrotic syndrome patterns:
- Frequently relapsing nephrotic syndrome (FRNS) is defined as ≥2 relapses within the first 6 months of diagnosis OR ≥4 relapses within any 12-month period 1
- Steroid-resistant nephrotic syndrome (SRNS) is defined as persistent proteinuria despite treatment with prednisone at 1 mg/kg/day or 2 mg/kg every other day for at least 4 months 1
Clinical Significance
The distinction between SDNS and FRNS is critical for treatment planning:
- Both SDNS and FRNS require steroid-sparing immunosuppressive agents to avoid cumulative corticosteroid toxicity 1, 2
- SDNS patients have a particularly tight temporal relationship between steroid dose reduction and relapse, indicating strong steroid dependency 1, 2
- The concept of "cyclosporin dependency" can develop in SDNS patients, where relapses occur when calcineurin inhibitor doses are reduced, similar to the original steroid dependency pattern 1
Common Pitfalls to Avoid
- Do not confuse SDNS with steroid resistance - SDNS patients initially respond to steroids but relapse during tapering, while steroid-resistant patients never achieve remission despite adequate steroid therapy 1
- Do not delay initiation of steroid-sparing agents in confirmed SDNS - these patients will have significant cumulative steroid exposure and develop serious glucocorticoid-related adverse effects including growth failure, obesity, hypertension, diabetes, osteoporosis, behavioral concerns, and cataracts 1, 3
- Recognize that SDNS can persist into adulthood - approximately one-third of pediatric SDNS patients will have active disease continuing into adulthood, requiring ongoing management 2, 4
Treatment Implications
Once SDNS is diagnosed:
- Calcineurin inhibitors (cyclosporine 4-5 mg/kg/day or tacrolimus 0.1 mg/kg/day) are first-line steroid-sparing agents 1, 2
- Alternative options include cyclophosphamide 2 mg/kg/day for 8-12 weeks, mycophenolate mofetil 1200 mg/m²/day, or rituximab 375 mg/m² for 1-4 doses 2
- Treat relapses with daily prednisone until remission for 3 days, then alternate-day prednisone for at least 3 months 2