Table 1.
Definitions
| Term | Definition |
|---|---|
| Nephrotic-range proteinuriaa | Urinary protein creatinine ratio (UPCR) ≥ 200 mg/mmol (2 mg/mg) in a spot urine, or proteinuria ≥ 1000 mg/m2 per day in a 24-h urine sample corresponding to 3 + (300–1000 mg/dL) or 4 + (≥ 1000 mg/dL) by urine dipstick |
| Nephrotic syndrome | Nephrotic-range proteinuria and either hypoalbuminemia (serum albumin < 30 g/L) or edema when serum albumin is not available |
| Complete remission | UPCR (based on first morning void or 24 h urine sample) ≤ 20 mg/mmol (0.2 mg/mg) or < 100 mg/m2 per day, respectively, or negative or trace dipstick on three or more consecutive days |
| Partial remission | UPCR (based on first morning void or 24 h urine sample) > 20 but < 200 mg/mmol (> 0.2 mg/mg but < 2 mg/mg) and serum albumin ≥ 30 g/L |
| Steroid-sensitive nephrotic syndrome (SSNS) | Complete remission within 4 weeks of PDN at standard dose (60 mg/m2/day or 2 mg/kg/day, maximum 60 mg/day) |
| Steroid-resistant nephrotic syndrome (SRNS) | Lack of complete remission within 4 weeks of treatment with PDN at standard dose |
| Confirmation period | Time period between 4 and 6 weeks from PDN initiation during which responses to further oral PDN and/or pulses of IV MPDN and RAASi are ascertained in patients achieving only partial remission at 4 weeks. A patient not achieving complete remission by 6 weeks, although partial remission was achieved at 4 weeks, is defined as SRNS |
| SSNS late responder | A patient achieving complete remission during the confirmation period (i.e. between 4 and 6 weeks of PDN therapy) for new onset NS |
| Relapse | Urine dipstick ≥ 3 + (≥ 300 mg/dl) or UPCR ≥ 200 mg/mmol (≥ 2 mg/mg) on a spot urine sample on 3 consecutive days, with or without reappearance of edema in a child who had previously achieved complete remission |
| Infrequently relapsing nephrotic syndrome | < 2 relapses in the 6 months following remission of the initial episode or fewer than 3 relapses in any subsequent 12-month period |
| Frequently relapsing nephrotic syndrome (FRNS) | ≥ 2 relapses in the first 6-months following remission of the initial episode or ≥ 3 relapses in any 12 months |
| Steroid-dependent nephrotic syndrome (SDNS) | A patient with SSNS who experiences 2 consecutive relapses during recommended PDN therapy for first presentation or relapse or within 14 days of its discontinuation |
| Steroid toxicity | New or worsening obesity/overweight, sustained hypertension, hyperglycemia |
| Behavioral/psychiatric disorders, sleep disruption | |
| Impaired statural growth (height velocity < 25th percentile and/or height < 3rd percentile) in a child with normal growth before start of steroid treatment | |
| Cushingoid features, striae rubrae/distensae, glaucoma, ocular cataract, bone pain, avascular necrosis | |
| Sustained remission | No relapses over 12 months with or without therapy |
| SSNS controlled on therapy | Infrequently relapsing NS or sustained remission while on immunosuppression in the absence of significant drug-related toxicity |
| SSNS not controlled on therapy | Either frequently relapsing NS despite immunosuppression or significant drug-related toxicity while on immunosuppression |
| Secondary steroid resistance | SSNS patient who at a subsequent relapse does not achieve complete remission within 4 weeks of PDN at standard dose |
| Complicated relapse | A relapse requiring hospitalization due to one or more of the following: severe edema, symptomatic hypovolemia or AKI requiring IV albumin infusions, thrombosis, or severe infections (e.g., sepsis, peritonitis, pneumonia, cellulitis) |
aIn adults, nephrotic range proteinuria is defined by proteinuria > 3.5 g/24 h (or > 3000 mg/g or > 3 g/10 mmol creatinine) [15]. These cut-offs should also apply to adolescents (> 16 years)