Nephrotic syndrome Flashcards
Causes of proteinuria
- orthostatic proteinuria
- glomerulonephritis
- increased glomerular filtration pressure
- reduced renal mass in CKD
- hypertension
- tubular proteinuria
- normal: febrile illness, after exercise (does not require investigation)
What is the nephrotic syndrome?
Heavy proteinuria, resulting in a low plasma albumin and oedema
Causes of nephrotic syndrome?
Primary cause unknown Can be secondary to systemic diseases: - Henoch-Schonlein purpura - SLE - infections - allergens
Clinical signs of the nephrotic syndrome
- periorbital oedema (particularly on walking)
- scrotal or vulval, leg and ankle oedema
- ascites
- breathlessness due to pleural effusions and abdominal distension
- infection such as peritonitis, septic arthritis or sepsis due to loss of protective immunoglobulins in the urine
What is steroid-sensitive nephrotic syndrome?
Proteinuria resolves with corticosteroid therapy (85-90%).
Do not progress to CKD
Epidemiology of steroid-sensitive nephrotic syndrome?
- M>F
- Asian > Caucasians
- Association with atopy
- Often precipitated by respiratory infections
Features suggesting steroid sensitive nephrotic syndrome
- age between 1-10 years
- no macroscopic haematuria
- normal BP
- normal complement levels
- normal renal function
Management of steroid-sensitive nephrotic syndrome
Oral corticosteroids (60mg/m2/day of prednisolone) unless atypical features.
After 4 weeks, dose is reduced to 40mg/m2 on alternate days for 4 weeks and then weaned or stopped
- leads to reduced frequency of relapse, however nb steroid S/Es
~11 days for urine to become free of protein
When is a more complex diagnosis considered?
When children do not respond to 4-6 weeks of corticosteroid therapy or have atypical featurs.
Renal biopsy these kids!!!
Complications at presentation/relapse:
- hypovolaemia
- thrombosis
- infection (esp Pneumococcus). Vaccinations - pneumococcus and influenza. Treat chickenpox and shingles with aciclovir
- hypercholesterolaemia
Indications of hypovolaemia?
Low urinary sodium (<10mmol/L) and a high packed cell volume of red blood cells
How to treat hypovolaemia?
IV fluid (0.9% saline) to reduce risk of vascular thrombosis and shock If severe may need treatment of IV 20% albumin infusion with furosemide --- NB can cause fluid overload and worsen hypovolaemia
Prognosis of steroid-sensitive nephrotic syndrome?
1/3 resolve directly
1/3 infrequent relapses
1/3 frequent relapses - steroid-dependent
Causes of steroid-resistant nephrotic syndrome?
- focal segmental glomerulosclerosis
- mesangiocapillary glomerulonephritis (membranoproliferative glomerulonephritis)
- membranous nephropathy
Features and prognosis of focal segmental glomerulosclerosis
- most common
- familial or idiopathic
- 30% progress to end-stage renal failure in 5 years
- 20% respond to cyclophosphamide, cyclosporin, tacrolimus or rituximab
- recurrence post-transplant is common
Features and prognosis of mesangiocapillary glomerulonephritis
- more common in older children
- haematuria and low complement level present
- decline in renal function over many years
Features and prognosis of membranous nephropathy
- associated with hep B
- may precede SLE
- most remit spontaneously within 5 years
Management of steroid-resistant nephrotic syndrome
- refer to paediatric nephrologist
- manage oedema with diuretic therapy, salt restriction, ACEIs, sometimes NSAIDs which may reduce proteinuria
What is congenital nephrotic syndrome?
Presents in first 3 months of life. Rare, recessively inherrited, more common in consanguinous families.
Associated with high mortality.
Manage with unilateral nephrectomy, followed by dialysis until child is no longer nephrotic and old enough for renal transplantation.
Investigations for presentation of nephrotic syndrome?
- urine dipstick - protein
- FBC and ESR
- U&E, Creatinine, albumin
- complement levels - C3,C4
- Antistreptolysin O or anti-DNAse B titres and throat swab
- urine microscopy and culture
- urinary sodium concentration
- hep B and C screen
- malaria screen if traveled abroad
