1 Pathophysiology of Nephrotic Syndrome
Madhura S Naidu (Physiology)
Ji Keon Looi (Pathology)
MED2031, Monash University Malaysia
Proteinuria
Hypoalbuminemia
Hyperlipidaemia
Oedema
Lipiduria
Nephrotic syndrome is caused by various disorders that damage
the kidneys, particularly the basement membrane of the
glomerulus.
This immediately causes abnormal excretion of protein in the
urine.
The concentration of heparan sulfate mucopolysaccharide in the basement membrane is lower, and large amounts of
protein cross the barrier and are excreted. Why?
High glomerular permeability leads to hyperalbuminuria and, eventually, to hypoalbuminemia.
In turn, hypoalbuminemia lowers the plasma colloid osmotic pressure, causing greater transcapillary filtration of
water and the development of edema.
In a steady state, the flux of water across the capillary wall can be expressed by the following formula
Qw = K ([Pc - Pi] - [pp - [pi])
Qw is net flux of water
K is the capillary filtration coefficient
Pc is plasma fluid hydrostatic pressure
Pi is the interstitial fluid hydrostatic pressure
pp is the plasma oncotic pressure
pi is the interstitial fluid oncotic pressure
9 Nephrotic Dyslipidemia
The two mechanisms contributing to dyslipidemia are:
• Increased production of lipoproteins
• Impaired catabolism of lipoproteins
~ The liver is the site of synthesis of lipids and albumin, therefore hypoalbuminemia leads to an increased
stimulus for synthesis of proteins and VLDL/LDL
Important enzymes involved in cholesterol catabolism leak out the GBM defect in
conversion/catabolism of lipoproteins
Therefore, increased VLDL/LDL & lipoprotein (a), normal or decreased HDL serum levels
10 Summary
11 Thank you
http://www.patient.co.uk/showdoc/27000748/
http://www.emedicine.com/med/topic1612.htm (By Mahendra Agraharkar)
http://www.nlm.nih.gov/medlineplus/ency/article/000490.htm
Guyton Textbook of Medical Physiology 11th edn
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