Nephrotic syndrome

Question 1

Causes of proteinuria

Answer 1

• orthostatic proteinuria
• glomerulonephritis
• increased glomerular filtration pressure
• reduced renal mass in CKD
• hypertension
• tubular proteinuria
• normal: febrile illness, after exercise (does not require investigation)

Question 2

What is the nephrotic syndrome?

Answer 2

Heavy proteinuria, resulting in a low plasma albumin and oedema

Question 3

Causes of nephrotic syndrome?

Answer 3

Primary cause unknown
Can be secondary to systemic diseases:
- Henoch-Schonlein purpura 
- SLE
- infections
- allergens

Question 4

Clinical signs of the nephrotic syndrome

Answer 4

• 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

Question 5

What is steroid-sensitive nephrotic syndrome?

Answer 5

Proteinuria resolves with corticosteroid therapy (85-90%).

Do not progress to CKD

Question 6

Epidemiology of steroid-sensitive nephrotic syndrome?

Answer 6

• M>F
• Asian > Caucasians
• Association with atopy
• Often precipitated by respiratory infections

Question 7

Features suggesting steroid sensitive nephrotic syndrome

Answer 7

• age between 1-10 years
• no macroscopic haematuria
• normal BP
• normal complement levels
• normal renal function

Question 8

Management of steroid-sensitive nephrotic syndrome

Answer 8

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

Question 9

When is a more complex diagnosis considered?

Answer 9

When children do not respond to 4-6 weeks of corticosteroid therapy or have atypical featurs.

Renal biopsy these kids!!!

Question 10

Complications at presentation/relapse:

Answer 10

• hypovolaemia
• thrombosis
• infection (esp Pneumococcus). Vaccinations - pneumococcus and influenza. Treat chickenpox and shingles with aciclovir
• hypercholesterolaemia

Question 11

Indications of hypovolaemia?

Answer 11

Low urinary sodium (<10mmol/L) and a high packed cell volume of red blood cells

Question 12

How to treat hypovolaemia?

Answer 12

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

Question 13

Prognosis of steroid-sensitive nephrotic syndrome?

Answer 13

1/3 resolve directly
1/3 infrequent relapses
1/3 frequent relapses - steroid-dependent

Question 14

Causes of steroid-resistant nephrotic syndrome?

Answer 14

• focal segmental glomerulosclerosis
• mesangiocapillary glomerulonephritis (membranoproliferative glomerulonephritis)
• membranous nephropathy

Question 15

Features and prognosis of focal segmental glomerulosclerosis

Answer 15

• 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

Question 16

Features and prognosis of mesangiocapillary glomerulonephritis

Answer 16

• more common in older children
• haematuria and low complement level present
• decline in renal function over many years

Question 17

Features and prognosis of membranous nephropathy

Answer 17

• associated with hep B
• may precede SLE
• most remit spontaneously within 5 years

Question 18

Management of steroid-resistant nephrotic syndrome

Answer 18

• refer to paediatric nephrologist

- manage oedema with diuretic therapy, salt restriction, ACEIs, sometimes NSAIDs which may reduce proteinuria

Question 19

What is congenital nephrotic syndrome?

Answer 19

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.

Question 20

Investigations for presentation of nephrotic syndrome?

Answer 20

• 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