Note: for patients ≥18 years of age, different definitions may be used.
Heavy (nephrotic range) proteinuria
Hypoalbuminemia (serum albumin <3.0 g/dL or <30 g/L)
Edema
Often present, especially at disease onset, but not required for diagnosis unless albumin level is not known
Hyperlipidemia (total cholesterol ≥200 mg/dL)
Almost always present and often severe (>350 mg/dL or >9.06 mmol/L), but not required for diagnosis
First morning urine protein/creatinine ratio (UPCR, PCR, UPC) ≥2.0 g/g (or ≥200 mg/mmol)
First morning urine protein ≥300 mg/dL
First morning urine dipstick with ≥3+ protein
UPCR is preferred over dipstick for establishing diagnosis
24-hour urine ≥40 mg/m²/hour
Complete remission: negative/trace first morning dipstick for ≥3 consecutive days
Alternatively, first morning UPCR ≤0.2 g/g (or ≤20 mg/mmol) Cr for ≥3 consecutive days
Sequential UPCR is rarely performed in the outpatient setting
Partial remission: sub-nephrotic range proteinuria (UPCR ≥0.2 but <2.0 g/g) and serum albumin ≥3.0 g/dL (30 g/L)
Recurrence of nephrotic range proteinuria for ≥3 consecutive days
Typically detected by home urine dipstick
Complete remission within 4 weeks of prednisone or prednisolone at a standard dose
Recommend avoiding use of "steroid responsive NS" as this can be confused with steroid resistant NS when abbreviated to SRNS
SSNS can be subclassified in terms of frequency of relapse:
≥ 2 relapses within 6 months of disease onset or ≥4 relapses in any subsequent 12 month period
Encompassess patients who do not meet criteria for frequently relapsing nephrotic syndrome:
No more than 1 relapse within 6 months of disease onset
No more than 3 relapses in any subsequent 12 month period
Two consecutive relapses during therapy with prednisone or prednisolone (either at full daily dose or during tapering) or within 15 days of stopping steroids
In other words, patients with SDNS are unable to come off steroids for >2 weeks without relapsing
Lack of complete remission after 4 weeks of therapy with daily prednisone or prednisolone at standard dose
Achieved complete remission after 4 weeks but before 6 weeks of daily steroid therapy
Partial remission is achieved within 6 months of treatment and/or complete remission is achieved within 12 months of treatment with a CNI at adequate doses and/or levels
Partial remission is not achieved after 6 months of treatment with a CNI at adequate doses and/or levels
Absence of complete remission after 12 months of treatment with two steroid sparing agents
The two steroid sparing agents must have distinct mechanisms and be administered at standard doses
When a patient with SSNS at disease onset has a subsequent relapse in which they are a late responder
Zotta F, Vivarelli M, Emma F. Update on the treatment of steroid-sensitive nephrotic syndrome. Pediatr Nephrol. 2022;37(2):303-314. doi:10.1007/s00467-021-04983-3