Nephrotic Syndrome

Question 1

What is nephrotic syndrome?

Answer 1

Nephrotic syndrome is due to protein being lost at the kidneys, it causes low serum protein which leads to peripheral and pulmonary oedema

Question 2

What causes nephrotic syndrome?

Answer 2

Damage to the glomeruli which allows proteins to enter the filtrate which in healthy state they should not, there is disruption of the podocytes and basement membrane

Question 3

What are some complications of nephrotic syndrome

Answer 3

Infection- loss of immunoglobulin in the serum causes a weakened immune system
Oedema- Reduced oncotic pressures causing peripheral and pulmonary oedema
VTE- Due to loss of proteins involved in coagulation control
AKI- this is due to reduced circulating volume

Question 4

What is the protein level in the urine greater than in nephrotic syndrome?

Answer 4

Greater than 3 g in 24 hours

Question 5

What are the serum/urine features of nephrotic syndrome?

Answer 5

Serum-
Low albumin
Low protein
High lipids/cholesterol (due to liver compensatory mechanisms for low albumin)

Urine-
High protein (>3g/24hr, A:CR >350ng/mmol)
Frothy urine (think O in froth and o in nephrotic and o in protein, oooooooooooo)

Question 6

How might you divide the causes of nephrotic syndrome?

Answer 6

Primary causes- due to disease that primarily affects the kidneys
Secondary causes- due to systemic processes that have renal involvement. e.g. HIV, SLE, Myeloma

Question 7

Name three primary causes of nephrotic syndrome

Answer 7

Minimal change glomerulonephritis
Focal segmental glomerulosclerosis
Membranous glomerulonephritis

Question 8

Name three secondary causes of diabetic nephropathy

Answer 8

Diabetic nephropathy
SLE- Lupus Nephritis
Myeloma kidney
HIV associated glomerulonephritis

Question 9

What happens in membranous glomerulonephritis?

Answer 9

Auto-anti bodies target the basement membrane or deposition of immune complexes in the glomerular basement membrane. This causes damage and disruption to the podocytes allowing proteins to enter the filtrate.

Most commonly affects caucasian adults

Question 10

What happens in focal segmental glomerulosclerosis?

Answer 10

Focal- Not all glomeruli affected
Segmental- Only part of glomerulus affected

(It’s a histological diagnosis)

Majority of cases are idiopathic, there is disruption of podocytes that allows proteins to enter the filtrate.

Question 11

What conditions have been associated with FSGS?

Answer 11

Sickle cell disease
HIV associated glomerulonephropathy
Heroin abuse

Question 12

If suspecting nephrotic syndrome, you would normally do a renal biopsy, but when would this not be done?

Answer 12

If it is a child

This is likely to be minimal change disease which is steroid responsive, so treat with steroids first

Question 13

How is FSGS often treated?

Answer 13

Steroids

Question 14

What is minimal change disease?

Answer 14

The most common cause of nephrotic syndrome in children, biopsy is rarely done because this can be treated with steroids first. There is damage to the foot processes of podocytes- thought to be due to T-cell activity but the details are not known.

Most common cause of nephrotic syndrome in children

Question 15

What are some secondary causes of nephrotic syndrome?

Answer 15

HIV associated glomerulosclerosis- causes FSGS
Myeloma kidney
Diabetic nephropathy

Question 16

How does diabetes lead to diabetic nephropathy?

Answer 16

Glycosylation of basement membrane proteins causes mesangial expansion (formation of Kimmelsteil-Wilson nodules) which disrupts podocytes and filtration slits. There is also hyaline arteriosclerosis which causes glomerulosclerosis. Results in albumin and other proteins entering the filtrate.

Question 17

What is the management for nephrotic syndrome?

Answer 17

General measures- salt and water restriction, loop diuretics, ACEi or ARB

Specific treatments-

• Immunosupression e.g. steroids, methotrexate, ciclospoin, azathioprin
• Plasma exchange
• HAART for HIV
• Myeloma- Dexamethasone, Cyclophosphamide and Thalidomide