What are the presentation, symptoms, signs, differential diagnosis, and practical questions to ask in a pediatric nephrotic syndrome case?

Pediatric Nephrotic Syndrome: Case Taking Guide for Practicals

Clinical Presentation

Pediatric nephrotic syndrome classically presents with periorbital edema (most noticeable in the morning), progressing to generalized edema including ascites and scrotal/labial swelling, accompanied by frothy urine. 1, 2

Key Symptoms to Elicit:

• Edema pattern: Periorbital puffiness (morning), ankle swelling (evening), abdominal distension
• Urine changes: Frothy/foamy appearance, reduced volume
• Constitutional symptoms: Fatigue, decreased appetite, irritability
• Recent infections: Upper respiratory tract infections often precede onset or trigger relapses 3
• Weight gain: Rapid increase due to fluid retention

Physical Signs to Demonstrate:

• Edema: Pitting edema in dependent areas, periorbital swelling, ascites (shifting dullness, fluid thrill)
• Vital signs: Usually normal blood pressure (distinguishes from nephritic syndrome), normal temperature unless infected
• Skin changes: Shiny, stretched skin over edematous areas; striae if on steroids
• Respiratory: Pleural effusions causing decreased breath sounds and dullness to percussion
• Cardiovascular: Normal heart sounds, no signs of heart failure
• Absence of: Gross hematuria, hypertension, signs of chronic liver disease 4, 5

Differential Diagnosis

Primary Nephrotic Syndrome (Most Common in Children):

• Minimal change disease (85-90% in children 1-10 years) - most likely diagnosis 5, 2
• Focal segmental glomerulosclerosis (10-15%)
• Membranoproliferative glomerulonephritis (rare)
• Membranous nephropathy (rare in children)

Secondary Causes to Exclude:

• Systemic lupus erythematosus (lupus nephritis) - check for rash, arthritis, fever 5
• Henoch-Schönlein purpura - look for purpuric rash, abdominal pain
• Hepatitis B/C infection
• HIV-associated nephropathy
• Malignancy-associated (rare)
• Drug-induced (NSAIDs, gold, penicillamine)

Conditions to Differentiate From:

• Nephritic syndrome: Hematuria, hypertension, reduced GFR, less severe proteinuria 5
• Acute glomerulonephritis: Gross hematuria, hypertension, oliguria
• Congestive heart failure: Elevated JVP, hepatomegaly, cardiomegaly
• Chronic liver disease: Jaundice, spider nevi, hepatosplenomegaly, no heavy proteinuria 4
• Protein-losing enteropathy: Diarrhea, no proteinuria
• Malnutrition/kwashiorkor: Poor nutritional history, no proteinuria

Essential Questions for Practical Examination

History Taking - Disease Characterization:

1. Onset and duration: "When did you first notice the swelling? Which part of the body swelled first?"
2. Urine appearance: "Have you noticed any changes in the urine color or foaminess?"
3. Previous episodes: "Has this happened before? How many times?" (defines relapse pattern) 3
4. Infection triggers: "Did your child have a cold, sore throat, or any infection before the swelling started?" 3

Treatment History (Critical for Classification):

1. Steroid response: "Has your child received steroids before? Did the swelling go away with steroids? How quickly?" (defines steroid-sensitive vs resistant) 3
2. Relapse frequency: "How many times has the swelling come back in the last 6 months? In the last year?" (defines frequently-relapsing vs infrequently-relapsing) 3
3. Current medications: "What medicines is your child taking now? Any immunosuppressants like cyclosporine, tacrolimus, or rituximab?" 3
4. Steroid toxicity: "Have you noticed growth problems, weight gain, mood changes, or bone problems?" 3

Complications Assessment:

1. Infection risk: "Any fever, abdominal pain, or signs of infection?" (spontaneous bacterial peritonitis risk) 2
2. Thrombosis symptoms: "Any limb pain, swelling in one leg, chest pain, or breathing difficulty?" 4, 2
3. Acute kidney injury: "Has urine output decreased significantly?" 2

Family and Genetic History:

1. Family history: "Does anyone in the family have kidney disease or nephrotic syndrome?" (genetic forms) 6
2. Ethnicity: "What is your ethnic background?" (higher incidence in Asian and Black populations) 2

Monitoring and Compliance:

1. Home monitoring: "Do you check urine protein at home with dipsticks? What were recent readings?" 2
2. Medication adherence: "Are you able to give all medications as prescribed? Any difficulties?" 2

Laboratory Findings to Discuss

Diagnostic Triad (Define Nephrotic Syndrome):

• Heavy proteinuria: >3+ on dipstick, protein:creatinine ratio >2 mg/mg (>200 mg/mmol), or 24-hour protein >3 g 4, 5
• Hypoalbuminemia: Serum albumin <3.0 g/dL (30 g/L) 4, 5
• Edema: Clinical finding 4

Additional Expected Findings:

• Hyperlipidemia: Elevated cholesterol and triglycerides 4, 5
• Normal complement levels: C3, C4 normal (helps exclude lupus, post-infectious GN)
• Normal renal function: Creatinine usually normal initially
• Microscopic hematuria: May be present but not gross hematuria
• Lipiduria: Oval fat bodies, fatty casts on urine microscopy

Management Algorithm (Based on KDIGO 2025)

Initial Episode Treatment:

Give oral prednisone/prednisolone for either 8 weeks (4 weeks daily + 4 weeks alternate-day) or 12 weeks (6 weeks daily + 6 weeks alternate-day). 3 The 12-week regimen may reduce relapse risk but increases steroid exposure.

Relapse Management:

• For infrequent relapses without steroid toxicity: Repeat standard glucocorticoid regimen 3
• For frequent relapses with steroid toxicity: Shorter taper and initiate steroid-sparing agents 3
• Do NOT routinely give daily steroids during upper respiratory infections to prevent relapses (updated 2025 recommendation based on PREDNOS2 trial) 3

Steroid-Sparing Agents (When to Use):

Prescribe glucocorticoid-sparing agents for: (1) frequently-relapsing nephrotic syndrome with serious steroid toxicity, or (2) ALL children with steroid-dependent nephrotic syndrome. 3

Agent selection by disease pattern:

• Frequently-relapsing NS: Cyclophosphamide or levamisole preferred 3
• Steroid-dependent NS: Mycophenolate mofetil, rituximab, calcineurin inhibitors (cyclosporine/tacrolimus), or cyclophosphamide 3

Steroid-Resistant Nephrotic Syndrome:

Use cyclosporine or tacrolimus as initial second-line therapy. 3 Rituximab achieves remission in approximately 30% of calcineurin inhibitor-resistant cases 3.

Common Pitfalls to Avoid

1. Missing steroid-resistant NS: If no remission after 4-6 weeks of daily steroids, classify as steroid-resistant and switch to calcineurin inhibitors 3
2. Over-treating with steroids during infections: The 2025 guidelines now recommend AGAINST routine daily steroids during URTIs 3
3. Confusing nephrotic with nephritic syndrome: Nephritic has hematuria, hypertension, and worse prognosis 5
4. Delaying genetic testing: Consider in steroid-resistant cases, congenital NS, or positive family history 6, 7
5. Inadequate infection surveillance: High risk for spontaneous bacterial peritonitis and sepsis 2
6. Missing thrombotic complications: Hypercoagulable state requires vigilance 4, 2