Pediatric Nephrotic Syndrome

Peds Nephrology

Clinical Mastery

Definition & Pathophysiology

Understand the core definition of pediatric nephrotic syndrome and the underlying physiological mechanisms. This section breaks down the normal glomerular filtration barrier and illustrates the pathological cascade that leads to the clinical presentation.

The Core Tetrad (Exam Priority)

💧

Massive Proteinuria

>40 mg/m²/hr OR spot PCR >2

🦼

Hypoalbuminemia

<2.5 g/dL in serum

👶

Edema

Due to decreased oncotic pressure

🩸

Hyperlipidemia

Hepatic compensation mechanism

Physiology: Glomerular Filtration Barrier

Interact with the model below to see how podocyte injury leads to the core event of nephrotic syndrome.

Fenestrated Endothelium

Basement Mem. (Charge)

No Protein Leak

✓ Selective Filtration

• Endothelium, basement membrane, and podocyte slit diaphragms are intact.
• The barrier prevents protein loss (especially negatively charged albumin).
• Urine remains protein-free.

⚠ Core Event: Podocyte Injury

• T-cell mediated injury disrupts podocytes (in Minimal Change Disease).
• Loss of size and charge barrier selectivity.
• Result: Massive protein leak into the urinary space.

Pathophysiology Cascade

Hover over each step to see the clinical correlation resulting from the protein leak.

Podocyte Injury
Core Event

Leads to massive loss of plasma proteins into urine.

→

↓

Hypoalbuminemia
↓ Oncotic Pressure

Clinical Correlation: EDEMA. Fluid shifts from vasculature to interstitial space.

→

↓

Liver Compensation
↑ Lipoprotein Synth

Clinical Correlation: HYPERLIPIDEMIA. Liver increases synthesis to maintain oncotic pressure, producing excess lipids.

→

↓

Loss of Other Proteins
IgG & AT-III

Clinical Correlation:
Loss of Ig → Infections
Loss of Antithrombin III → Thrombosis

Etiology & Clinical Features

Explore the underlying causes (highlighting the predominance of Minimal Change Disease in children) and the classic symptoms and signs presented by patients.

Etiopathogenesis in Children

"In children, most cases are primary, with Minimal Change Disease being the commonest."

Types of Nephrotic Syndrome

Categorized primarily by response to steroid therapy, which dictates further management.

Meaning: Fully responds to standard steroid therapy (remission achieved).

Most common outcome in children (typical of Minimal Change Disease).

Meaning: Responds to steroids initially, but relapses consistently while tapering the dose or within 14 days of stopping.

Requires steroid-sparing immunosuppressants.

Meaning: No response (failure to achieve remission) after 4 weeks of daily steroid therapy.

Indication for Renal Biopsy.

Clinical Presentation

👦 Symptoms

• ✔ Facial puffiness (esp. in the morning)
• ✔ Reduced urine output
• ✔ Frothy urine (due to protein)
• ✔ Abdominal distension

🔍 Signs

• ✔ Periorbital edema
• ✔ Pedal edema (pitting)
• ✔ Ascites
• ✔ Pleural effusion (in severe cases)

⚠ Important Negatives

The presence of these points strongly away from simple Nephrotic Syndrome.

• ✘ NO Hematuria (gross)
• ✘ NO Hypertension

➡ If present, think NEPHRITIC Syndrome.

Diagnosis & Differential

Review the necessary investigations, compare with other causes of edema, and walk through the interactive clinical decision-making algorithm.

Core Investigations

🧪 Urine Analysis

Protein: ++++ (massive)

RBCs: None (classically)

💉 Blood Tests

Albumin: ↓ Decreased

Cholesterol: ↑ Increased

Creatinine: Normal / near-normal

📌

Renal Biopsy Indications

Not done routinely in children. Only indicated if:

• Steroid Resistant
• Atypical features (Age <1 or >10, gross hematuria, HTN, low C3)

Differential Diagnosis (Edema Child)

Condition	Key Differentiating Feature
Nephrotic Syndrome	Massive Proteinuria, Normal BP
Nephritic Syndrome	Hematuria + Hypertension
Liver Disease	Abnormal LFTs, Jaundice, Coagulopathy
Heart Failure	Cardiomegaly, JVP elevated, Gallop rhythm
Protein-Losing Enteropathy	GI symptoms (Diarrhea), Normal urinalysis

⚒ Interactive Clinical Algorithm

Patient presents: Child with generalized Edema.

What is your first clinical action?

✔ Correct: Urine Protein is ++++ (Present)

Next check: Is there significant Hematuria or Hypertension?

✔ Correct: Diagnosis is likely Primary Nephrotic Syndrome.

What is the initial Specific Management?

✔ Correct: Prednisolone started. Monitor for 4 weeks.

Did the patient respond to steroids (remission)?

🎉 Likely Minimal Change Disease (MCD)

The patient is Steroid-Sensitive. Taper steroids according to protocol. Monitor for relapses.

⚠ Steroid Resistant Nephrotic Syndrome

Next Step: Renal Biopsy is now indicated to determine the pathology (e.g., FSGS) and guide second-line immunosuppressive therapy.

Management & Complications

Learn the four pillars of nephrotic syndrome management, representing exam gold for treatment protocols, alongside severe complications to anticipate.

1 Specific Therapy

Prednisolone (First-line)

The cornerstone of treatment. Given daily for initially (e.g., 60mg/m² or 2mg/kg) to induce remission, then tapered.

2 Supportive Care

• ✔ Salt Restriction: Crucial for edema control.
• ✔ Diuretics: Use carefully (risk of hypovolemia). Furosemide often used.
• ✔ Albumin IV: Only in severe cases (refractory edema, severe hypovolemia).

3 Relapse Management

Relapses are common. Triggered often by minor viral illnesses.

• ➜ Action: Repeat steroid course until urine is protein-free for 3 days.
• ➜ Freq Relapsers/Dependent: Consider immunosuppressants (Cyclophosphamide, Tacrolimus, Rituximab).

4 Complication Mgmt

• ⚠ Infection (e.g., SBP): Prompt IV antibiotics (often targeted at encapsulated orgs like Pneumococcus).
• ⚠ Thrombosis: Anticoagulation if a clot develops.

💻 Clinical Calculator: Steroid Dosing

Calculate Induction and Tapering doses for Minimal Change Disease based on Body Surface Area (BSA) or Weight. Utilizes maximum threshold limits (60mg/day).

Patient Weight (kg)

Patient Height (cm) (Required for BSA via Mosteller)

Estimated BSA

-- m²

Induction Dose (4 Weeks)

-- mg daily

Based on 60 mg/m² (or 2 mg/kg). Daily max 60mg.

Taper Dose (Next 4 Weeks)

-- mg alternate days

Based on 40 mg/m² (or 1.5 mg/kg).

Enter weight and height to view standard KDIGO dosing guidelines.

💉 Immunization Rules

• ✔ Inactivated Vaccines: Safe and highly recommended (e.g., Pneumococcal PCV13/PPSV23, Influenza).
• ✘ Live Vaccines (MMR, Varicella): ABSOLUTELY CONTRAINDICATED while on daily high-dose steroids.
• ➜ Defer live vaccines until off high-dose steroids for at least 4 weeks, or on a low-dose alternate-day regimen (<0.5 mg/kg).

💬 Parent Counseling Script

• 📊 Home Monitoring: Teach parents to use early morning urine dipsticks. 3+ protein for 3 consecutive days defines a Relapse.
• ⚠ Steroid Adherence: Never stop steroids abruptly to prevent Addisonian crisis.
• 🏃 Lifestyle: Encourage normal schooling and physical activity during remission. Overall renal prognosis is excellent.

Major Complications

🦠

Infections

Spontaneous Bacterial Peritonitis (SBP) is classic due to ascites + IgG loss.

🩸

Thrombosis

Due to loss of Antithrombin III and increased fibrinogen. RVT common.

💧

Hypovolemia

Intravascular volume depletion despite total body fluid overload.

🧀

AKI

Acute Kidney Injury, often prerenal due to severe hypovolemia.

Exam Assessment

Test your knowledge with Rapid Revision Flashcards and a Clinical Knowledge Quiz based on the source material.

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📝 Clinical Knowledge Quiz

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🚀 FINAL TAKE (Memorize this for Viva):
"Child with edema, proteinuria, hypoalbuminemia—likely nephrotic syndrome, most commonly minimal change disease. I would confirm with urine protein and start steroids."