|
|
Who will look at the biopsies?
|
Precisely who varies from place to place, but usually a consultant
histopathologist will look at the light microscopy, and the immunofluorescence,
but often the electron microscopy examination is delegated to a
specialist electron microscopist. (The ACEM exists to provide professional
support for these particular scientists.)
Why is electron microscopy necessary?
The electron microscope can see more detail and magnify to a much
greater extent than a light microscope. The detail seen is important
in arriving at an accurate diagnosis.
|
normal kidney on EM grid
- click to enlarge.
|
Renal diseases in which an electron microscopical examination is particularly
important.
- Alport’s disease. In this disease the glomerular basement
membrane is particularly fragile and is prone to allowing blood to leak
out into the urine. This is diagnosed by looking at the glomerular basement
membrane.
 Alport's
disease
- Hereditary thin basement membrane disease. This is similar
to Alport’s but usually doesn’t result in renal failure. This
is diagnosed by measuring the thickness of the glomerular basement membrane.
thin
basement membrane disease
- Amyloid. This is a condition in which a protein, which isn’t
normally there, is deposited around small blood vessels and in glomeruli.
This protein is seen by electron microscopy as a mass of tiny fine straight
filaments. amyloid
- Immune complex nephritis. This diagnosis covers a large number
of different types of immune complexes, which are deposited in different
parts of the glomerulus. By electron microscopy these clumps of antibodies
are seen as dense lumps in the basement membrane. Examples of immune
complex nephritis are: IgA disease, SLE, Membranous, and Membranoproliferative
glomerulonephritis, IgM disease, etc etc. immune
complex nephritis
- Vasculitis. This is a disease in which the body’s own
immune system attacks blood vessels and the kidney glomeruli. Typically
there are tiny clots in the glomerular capillaries and small areas in
which the capillaries rupture allowing blood to leak out. vasculitis
- Nephrotic syndrome. This is when the amount of protein loss
in the urine due to damage to the glomerular basement membrane is so
large that the body starts to retain fluid. This can be the consequence
of any of the above; typically the podocyte cell layer is severely damaged
allowing large amounts of protein to leak out into the urine.
Summary:
Electron microscopy is needed to find out which of the above or a large
number of other conditions is responsible for these and many other renal
problems. Some of these diseases are inherited, some are caused by infections,
but most are caused by mechanisms not fully understood. Electron microscopists
are not only involved in the diagnosis of renal disease but often also
in research aimed at acquiring a greater understanding of these disorders.
back to renal biopsies 1
|
