Paediatric Nephrotic Syndrome

ACEM Fellowship

Table of Contents

Definition

Heavy proteinuria (>50mg/kg per 24 hours), hypoalbuminaemia (<30g/L), oedema and hyperlipidaemia (triglycerides and cholesterol)
- Do not need all components for diagnosis
Plasma proteins up to MW of albumin are lost
- In severe disease, IgG loss approaches that of albumin
- Protein selectivity is seen in minimal change disease and increases the likelihood of a steroid responsive illness

90% of cases
Disease limited to the kidney
Steroid-sensitive: Responds fully within 4-6 weeks of therapy
Steroid-dependent: 2 consecutive relapses during steroid therapy or within 14 days of cessation
Steroid-resistant: Failure to achieve response after 4 weeks of steroids
DDx
- Minimal change disease (85%)
- Mesangial proliferative GN (5%)
- Focal segmental glomerusclerosis (10%)

Features that suggest secondary NS

Results from renal protein wasting
Increased blood viscosity
Blood flow reduced
Fibrinogen levels raised
Antithrombin III lost in urine
Presentations
- DVT
- Renal vein thrombosis – Macroscopic haematuria, palpable kidney, loin tenderness, raised creatinine, HTN
- Cerebral vein thrombosis – Headache, vomiting, impaired consciousness or focal neurology

Possibly due to reduced plasma oncotic pressure with subsequent stimulation of lipoprotein synthesis

Hypoalbuminaemia (<30) occurs in all children with nephrotic syndrome
Spot urine protein:creatinine ratio >300mg/nmol
Microscopic haematuria in 15%
Urinalysis proteinuria 3+ or 4+
Haematocrit often elevated
Plasma urea and creatinine elevated in 25% (if not mild, consider nephritic syndrome)
Serum complement levels are normal in MCNS, FSGS and mesangioproliferative GN
Hypertension (may be mild in first 1-2 days)
C3/4 (low in SLE and MPGN) and ANA (SLE)

Steroid-responsive: If urine becomes free of protein within 4-8 weeks of daily prednisolone
Steroid-resistant: Proteinuria >2+ despite 4-8 weeks of therapy. Renal biopsy indicated
Renal biopsy also indicated if other signs suggest secondary nephrotic syndrome

Treat hypotension/shock as normal
Albumin infusion of 20% can be considered for volume replacement if severely volume deplete or severely oedematous but is only a temporising measure and does risk acute pulmonary oedema
- Should be given with frusemide
If symptomatic from oedema, trial of diuretics can be considered (if not volume deplete)
Low salt diet
Strict fluid balance
Therapeutic paracentesis can be considered for acute respiratory distress from increased abdominal pressure
Prednisolone 1mg/kg BD sees proteinuria resolve in 90% within 4-6 weeks
Always consider peritonitis in the child with abdominal ascites
Pen V antibiotic prophylaxis until oedema subsides
Ranitidine as chemoprophylaxis against steroid-induced gastritis

Outpatient management if looks well, oedema is not massive and no complications apparent if close follow-up possible
Admission
- Recurrent, severe dehydration, unexplained fever, renal insufficiency, refractory oedema or suspected peritonitis
- Age <12 months or >12yo
- Persistent hypertension or microscopic haematuria
- C3 or C4 depletion
- Unclear if nephritic or nephrotic

Steroid-responsive: 1-2% mortality long-term
Most deaths due to peritonitis or sepsis (pneumonia) and thrombus
80% of children with minimal change disease will suffer a relapse and 50% will have frequent relapses
Relapses may continue through to adulthood but are usually less severe and respond well to steroids
Recovery considered permanent if remains asymptomatic and no requirement for medication for 2 years

Hypogammaglobulinaemia
Spontaneous bacterial peritonitis
Thromboembolism
Symptomatic hypovolaemia
Respiratory compromise
Hypertensive encephalopathy (on steroid therapy)
Benign intracranial hypertension (may be precipitated by abrupt stop in steroid dose)
Growth impairment (steroid therapy)

Last Updated on November 10, 2021 by Andrew Crofton