Nephrotic Syndrome Flashcards
Where do the glomerular endothelial cells lie?
They line the inner side of the glomerular basement membrane (GBM)
Where are the glomerular mesangial cells located?
Centrally
What do the mesangial cells secrete?
Basement membrane-like matrix that acts as a structural support for the glomerulus.
What are two other unique features of the mesangial cells?
- They have smooth muscle-like properties and can contract to affect surface area and filtration
- They have some macrophage-like properties, including the ability to secrete cytokines, growth factors, proteases, adn oxidants.
What is the most important barrier to protein?
The filtration slit diaphragm between the poocytes.
What constitutes the charge barrier?
The negatively charge basement membrane, and the negative coating on the endothelium and podocytes.
What is the most important structure for the size barrier?
The slit pore diaphragm
The primary protein in the slit diaphragm is ____
Nephrin.
It interlaces like a zipper and excludes many proteins. If nephrin is mutated, problems happen.
How much albumin is normally excreted daily?
Less than 20mg
What is the range for microalbuminuria?
30-300mg/day
Of what is persistent microalbuminuria suggestive?
Early glomerular damage, often seen in diabetic patients.
Albumin between ___ and ___ may be due to either glomerular or tubular disease.
300mg and 1-2gm/day
Once albumin increases above ____, there is a defect in glomerular permeability
3gm/day
Once albumin increases above 3gm/day, there is a defect in _____
Glomerular permeability
If you have a patient with large (>20gm/day) amounts of protein, but a negative dipstick, what might they have?
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.
What are the 5 hallmark findings of the nephrotic syndrome?
- Proteinuria
- Hypoalbuminemia
- Edema
- Hyperlipidemia
- Lipiduria
Where does the hypoalbuminemia come from?
Increased catabolism of reabsorbed protein in the renal tubules and from the urinary losses
Where does the edema come from?
- Decrease in serum albumin leads to a decrease in oncotic pressure and a movement of fluid into the interstitial space
- A defect in sodium excretion, resulting in volume expansion.
Test presentation: Child or 55yo with edema, history of allergies, normal complement levels, hypoalbuminemia, normal microscopy, normal IF.
Minimal change disease.
Treatment for minimal change disease
Steroid therapy
Test presentation: African American or young adult, present with nephrotic syndrome, sclerosis in some glomeruli, negative IF. Patient may use heroine or have HIV.
FSGS
Treatment for FSGS
Prolonged steroid therapy
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.
Membranous nephropathy
Treatment for membranous nephropathy
Steroids and cytotoxic drugs. ACEi to lower proteinuria
Test presentation: Female or adolescent child, hypertension, nephrotic syndrome, low C3 levels. Maybe HCV, rheumatoid factor.
MPGN
Treatment for MPGN
It’s a pretty bad prognosis. Maybe alternate-day steroids, maybe anti-platelet agents. Antivirals in HCV patients.
What is the most common cause of nephrotic syndrome in adults?
Diabetes.
Treatment for diabetic nephropathy
Control the beetus
T/F: SLE-caused nephrotic syndrome is accompanied by elevated ANA.
F. These patients actually have lower ANA than most other SLE patients.
