Focal Segmental Glomerular Sclerosis (FSGS) is a group of glomerular diseases
with proteinuria and Nephrotic Syndrome as main clinical manifestations and
lobular segmental sclerosis of sectional glomeruli as the pathological feature.
It can be divided into primary and secondary types. In addition, other
glomerular diseases with different pathology, such as Mesangial Proliferative
Glomerulonephritis, Membranous Proliferative Glomerulonephritis, IgA
Nephropathy, Lupus Glomerulonephritis, Purpura Glomerulonephritis and so on, may
show pathological changes of FSGS in a certain stage.
1. Clinical Manifestations:
a. It commonly occurs among teenagers, more in boys than in girls.
b. Latent onset.
c. 75% of patients have hematuria and 20% show gross hematuria.
d. Patients always suffer from declined renal functions and high blood
pressure, and they may also get proximal tubular dysfunction which manifests
Nephrotic Diabetes, aminoaciduria and phosphaturia.
2. Test by Optical Microscope (universally acknowledged pathological
classification standard)
FSGS is characterized by the focal segmental damage of glomeruli, with the
manifestations as that sectional glomeruli or part of glomerular lobules show
segmental sclerosis and the unaffected glomeruli remain normal or present slight
mesangial proliferation. Generally, the glomeruli that are located at the deep
part of renal cortex or the junction between cortex and medulla get affected
first, and only 1 to 3 vascular loops of glomeruli are attacked. In the early
stage of the disease, renal epithelial cells show proliferation and swelling and
in serious conditions, false crescents may occur. With the development of the
disease, more and more gomeruli become hardened and show global sclerosis, and
the other comparatively healthy glomeruli get compensatory hypertrophy. The
renal tubular mesenchyme always gets diseased, which may manifest atrophic renal
tubules, interstitial fibrosis, infiltration of inflammatory cells and thickened
arteriole wall.
3. Immunofluorescence Test
IgM and C3 deposit at the diseased parts of affected glomeruli in particle or
group shapes. The unaffected glomeruli are generally negative or have IgM and C3
sedimentation in mesangial area but almost have no IgG and IgA
sedimentation.
4. Test by Electron Microscope
The glomerular visceral epithelial cells present massive foot process fusion
and break away from glomerular basilar membrane, which are the early
pathologies. There are electron dense deposits under endothelial cells and at
mesangial region of affected glomeruli. At the sclerotic parts of glomeruli, the
blood capillaries shrink and electron-dense materials deposit there.