Nephrotic syndrome Flashcards
The glomerulus is a specialized capillary network which interacts with both (1) cells
- visceral and parietal epithelial
The (1) cells interact with the glomerular capillary (2) to form (3) with specialized foot processes that contribute to the filtration barrier
- visceral epithelial
- basement membrane
- podocytes
The (1) cells line the urinary space which becomes the (2) for each nephron
- parietal epithelial
2. proximal convoluted tubule
Because the glomerulus is designed to filter large quantities of blood, it has a three part filtration barrier. The first is the (1) (essentially holes) within (2) in the glomerular capillaries. Next is the glomerular (3) and the third is the (4)
- fenestrations
- endothelial cytoplasm
- basement membrane
- foot processes/slit diaphragm design of the epithelial podocytes.
This triple barrier is designed for high volume filtration of blood which allows (1) in the filtrate in the urinary space but keeps (2) in the blood stream
- water, ions, and small molecules
2. proteins
Ions, water, and small molecules present in the urinary space can be (1) from the tubular system into the post-glomerular blood stream. Certain ions and small molecules can also be (2) from the post-glomerular blood into the tubules
- reabsorbed
2. secreted
The charge barrier is primarily the (1), which consists of (2) as well as (3)
- basement membrane
- Type IV collagen
- negatively charged glycosaminoglycans such as heparan sulfate.
This strong negative charge prevents negatively charged proteins like (1) from being filtered into the urinary space
- albumin
In constrast to the charge barrier, the size barrier is primarily determined by the (1), which have a complex structure of (2) which may represent an actual pore for entry of certain molecules
- epithelial podocytes
2. foot processes and a slit diaphragm
Specific mutations in genes whose gene products are components of the slit diaphragm (such as (1), can lead to (2), providing some evidence that the slit diaphragm has an important role in maintaining the filtration barrier.
- nephrin or podocin
2. proteinuria
(1) can also increase the size exclusion barrier by allowing some larger molecules to enter the urinary space
- Fenestrations in capillary endothelial cell cytoplasm
Although (1) may not directly contribute to the filtration barrier, they are very important supportive cells (2), which provide both mechanical support and key functions.
- mesangial cells
2. modified smooth muscle cells
The mesangial cells process (1) so they are important for elimination of immune damage. They also provide the (2) functions of the glomeruli and generate (3) and other modulators
- plasma proteins and immune complexes by endocytosis
- contractile
- cytokines
Immunological damage to the glomeruli can either produce predominantly (1) (nephrotic symptoms and signs) or predominantly (2) (nephritic symptoms and signs).
- protein loss
2. bleeding and more severe injury
Clinically, patients with heavy proteinuria have the (1) syndrome which consists of proteinuria (usually 3.5 grams of protein in a 24 hour urine collection), (2)
- nephrotic
2. hypoalbuminemia, edema, hyperliipidemia, and lipiduria
The proteinuria leads directly to the (1) because the kidney is excreting the protein from blood into urine.
- hypoalbuminemia or low serum albumin
The hypoalbuminemia causes (2) because of the decreased plasma oncotic pressure from decreased serum proteins.
- edema (fluid within tissues)
The hyperlipidemia occurs because the (1) produces more (2) in the generalized response to produce more (3).
- liver
- lipoproteins
- albumin
(1) happens because of the increased lipoproteins carrying lipid and because of loss of the filtration barrier.
- Lipiduria (lipid in urine)
There can be extensive (1) in patients without any histopathological changes that can be seen by light microscopy
- proteinuria
However, ultra-structural changes can be seen by electron microscopy generally show (1) in nephrotic syndrome.
- fusion of the epithelial podocyte foot processes
There also can be pathologic changes identified by immune microscopy which identifies whether certain (1) are present in the glomeruli.
- immunoglobulins or complement
Minimal change disease (also called (1) is the most common cause of nephrotic syndrome in children and also can cause nephrotic syndrome in adults. Children who do not develop any complications have a completely normal life span without any later renal disease.
- nil lesion
Examination of a renal biopsy by light microscopy in minimal change disease show no pathologic changes, but (1) can be identified by electron microscopy
- fusion of foot processes in visceral epithelial cells (podocytes)