Nephrotic Syndrome

Question 1

Where do the glomerular endothelial cells lie?

Answer 1

They line the inner side of the glomerular basement membrane (GBM)

Question 2

Where are the glomerular mesangial cells located?

Answer 2

Centrally

Question 3

What do the mesangial cells secrete?

Answer 3

Basement membrane-like matrix that acts as a structural support for the glomerulus.

Question 4

What are two other unique features of the mesangial cells?

Answer 4

1. They have smooth muscle-like properties and can contract to affect surface area and filtration
2. They have some macrophage-like properties, including the ability to secrete cytokines, growth factors, proteases, adn oxidants.

Question 5

What is the most important barrier to protein?

Answer 5

The filtration slit diaphragm between the poocytes.

Question 6

What constitutes the charge barrier?

Answer 6

The negatively charge basement membrane, and the negative coating on the endothelium and podocytes.

Question 7

What is the most important structure for the size barrier?

Answer 7

The slit pore diaphragm

Question 8

The primary protein in the slit diaphragm is ____

Answer 8

Nephrin.

It interlaces like a zipper and excludes many proteins. If nephrin is mutated, problems happen.

Question 9

How much albumin is normally excreted daily?

Answer 9

Less than 20mg

Question 10

What is the range for microalbuminuria?

Answer 10

30-300mg/day

Question 11

Of what is persistent microalbuminuria suggestive?

Answer 11

Early glomerular damage, often seen in diabetic patients.

Question 12

Albumin between ___ and ___ may be due to either glomerular or tubular disease.

Answer 12

300mg and 1-2gm/day

Question 13

Once albumin increases above ____, there is a defect in glomerular permeability

Answer 13

3gm/day

Question 14

Once albumin increases above 3gm/day, there is a defect in _____

Answer 14

Glomerular permeability

Question 15

If you have a patient with large (>20gm/day) amounts of protein, but a negative dipstick, what might they have?

Answer 15

Multiple myeloma.

They produce large amounts of monoclonal light chains, which end up in the urine because they are small. A dipstick only responds to albumin.

Question 16

What are the 5 hallmark findings of the nephrotic syndrome?

Answer 16

1. Proteinuria
2. Hypoalbuminemia
3. Edema
4. Hyperlipidemia
5. Lipiduria

Question 17

Where does the hypoalbuminemia come from?

Answer 17

Increased catabolism of reabsorbed protein in the renal tubules and from the urinary losses

Question 18

Where does the edema come from?

Answer 18

1. Decrease in serum albumin leads to a decrease in oncotic pressure and a movement of fluid into the interstitial space
2. A defect in sodium excretion, resulting in volume expansion.

Question 19

Test presentation: Child or 55yo with edema, history of allergies, normal complement levels, hypoalbuminemia, normal microscopy, normal IF.

Answer 19

Minimal change disease.

Question 20

Treatment for minimal change disease

Answer 20

Steroid therapy

Question 21

Test presentation: African American or young adult, present with nephrotic syndrome, sclerosis in some glomeruli, negative IF. Patient may use heroine or have HIV.

Answer 21

FSGS

Question 22

Treatment for FSGS

Answer 22

Prolonged steroid therapy

Question 23

Test presentation: 55yo male, nephrotic presentation, normal complement, thickened GBM on light microscopy, spikes on silver stain, IF shows deposits on GBM. Maybe HepB, drugs, lupus, or cancer.

Answer 23

Membranous nephropathy

Question 24

Treatment for membranous nephropathy

Answer 24

Steroids and cytotoxic drugs. ACEi to lower proteinuria

Question 25

Test presentation: Female or adolescent child, hypertension, nephrotic syndrome, low C3 levels. Maybe HCV, rheumatoid factor.

Answer 25

MPGN

Question 26

Treatment for MPGN

Answer 26

It’s a pretty bad prognosis. Maybe alternate-day steroids, maybe anti-platelet agents. Antivirals in HCV patients.

Question 27

What is the most common cause of nephrotic syndrome in adults?

Answer 27

Diabetes.

Question 28

Treatment for diabetic nephropathy

Answer 28

Control the beetus

Question 29

T/F: SLE-caused nephrotic syndrome is accompanied by elevated ANA.

Answer 29

F. These patients actually have lower ANA than most other SLE patients.