Nephrotic syndrome

Question 1

Nephrotic syndrome triad?

Answer 1

Triad of:
1. Proteinuria (> 3g/24hr) causing
2. Hypoalbuminaemia (< 30g/L) and
3. Oedema

Question 2

Complications of nephrotic syndrome?

Answer 2

increased risk of thromboembolism related to loss of antithrombin III and plasminogen in the urine
- deep vein thrombosis, pulmonary embolism
- renal vein thrombosis, resulting in a sudden deterioration in renal function

hyperlipidaemia
- increasing risk of acute coronary syndrome, stroke etc

chronic kidney disease

increased risk of infection due to urinary immunoglobulin loss

hypocalcaemia (vitamin D and binding protein lost in urine)

Question 3

There are three other features that occur in patients with nephrotic syndrome:

Answer 3

Deranged lipid profile, with high levels of cholesterol, triglycerides and low density lipoproteins

High blood pressure

Hyper-coagulability, with an increased tendency to form blood clots

Question 4

Causes of nephrotic syndrome

Answer 4

The most common cause in children is minimal change disease, causing over 90% of cases in children under 10. In minimal change disease, nephrotic syndrome occurs in isolation, without any clear underlying condition or pathology. There are a number of secondary causes of nephrotic syndrome, where it occurs due to an underlying condition.

It can be secondary to intrinsic kidney disease:

Focal segmental glomerulosclerosis (FSGS)

Membranoproliferative glomerulonephritis (MPGN)

Membranous nephropathy

It can also be secondary to an underlying systemic illness:

Henoch schonlein purpura (HSP)
Diabetes
Infection, such as HIV, hepatitis and malaria

Question 5

Minimal Change Disease

Answer 5

Minimal change disease is the most common cause of nephrotic syndrome in children. It can occur in otherwise healthy children, without any clear risk factors or reason for developing the condition. It is not clear why it occurs in most cases.

A renal biopsy and standard microscopy in minimal change disease is usually not able to detect any abnormality. Urinalysis (analysis of the urine) will show small molecular weight proteins and hyaline casts.

Management of minimal change disease is with corticosteroids (i.e. prednisolone). The prognosis is good and most children make a full recovery, however it may reoccur.

Question 6

Nephrotic syndrome should be managed by experienced paediatricians with input from renal specialists. General management is with:

Answer 6

High dose steroids (i.e. prednisolone)
Low salt diet
Diuretics may be used to treat oedema
Albumin infusions may be required in severe hypoalbuminaemia
Antibiotic prophylaxis may be given in severe cases

Question 7

High dose steroids are given for 4 weeks and then gradually weaned over the next 8 weeks:

Answer 7

80% of children will respond to steroids, and are referred to as steroid sensitive

80% of steroid sensitive patients will relapse at some point and need further steroids

Patients that struggle to wean steroids due to relapses are referred to as steroid dependant

Patients that do not respond to steroids are referred to as steroid resistant

In steroid resistant children, ACE inhibitors and immunosuppressants such as cyclosporine, tacrolimus or rituximab may be used

Question 8

Nephrotic syndrome pathophysiology?

Answer 8

occurs when the basement membrane in the glomerulus becomes highly permeable to protein, allowing proteins to leak from the blood into the urine. It is most common between the ages of 2 and 5 years. It presents with frothy urine, generalised oedema and pallor.

Question 9

Symptoms of nephrotic syndrome?

Answer 9

Oedema
Frothy urine
Fatigue
Poor appetite
Recent infections
Hypercoagulability (MI or DVT)