Focal segmental glomerulosclerosis (FSGS) is not one but many different diseases.
How does the urinary system work?
The urinary system consists of the kidneys, ureters, the bladder and
urethra. The kidneys filter the blood to remove waste products and
produce urine. The urine flows from the kidneys down through the ureters
to the bladder, where it is stored until we go to the toilet. It passes
through another tube called the urethra to the outside when urinating
The kidneys contain millions of tiny filtering units called
glomeruli. As blood passes through the tubes in the glomerulus, waste
products pass through the walls of the tubes to form urine. Blood cells
and other things such as protein cannot pass through the walls because
they are too big.
When someone has focal
segmental glomerulosclerosis (FSGS), some of the glomeruli are damaged
and become scarred. This stops them working properly, so that protein
can pass through the walls of the glomerulus and into the urine. This
means that the child develops nephrotic syndrome.
Watch our animation to find out more about how the kidneys work.
What are the
symptoms of FSGS?
The main symptom of FSGS is the development of nephrotic syndrome,
that is, swelling due to increased fluid in the body. Nephrotic syndrome
occurs because the kidneys leak protein. This results in low protein
levels in the blood, which means that fluid is shifted out of vessels
into tissues. This causes puffiness, particularly around the eyes,
abdomen, feet and legs, and weight gain. The medical word for this
puffiness is oedema. As the kidney leaks protein, the urine’s appearance
changes so that it appears foamy, which is a sign of proteinuria.
How is FSGS diagnosed?
Your doctor will ask you lots of questions about how your child
became ill and examine your child. Various tests will be needed to
confirm or rule out FSGS:
- Urine tests to see how much protein is present in the urine.
- Blood tests to check general health, and possibly genetic tests, which we will discuss with you.
- Kidney biopsy to see if any areas contain scarring.
Other tests may also be needed if the results of these tests are not completely clear.
What causes FSGS?
There are many different kinds of FSGS. Some are caused by inherited
diseases and can thus affect several members of the family. In other
cases the cause is unknown and it might be caused by an autoimmune
reaction, where the body starts to attack itself after mistakenly
recognising itself as the ‘enemy’.
How common is FSGS?
We do not yet know exactly how many children each year are affected
by FSGS but at Great Ormond Street Hospital, we have looked after at least 66 children with this
condition over the last 15 years.
Reports vary but it would seem that
between seven and ten per cent of kidney biopsies to investigate
proteinuria lead to a diagnosis of FSGS. It seems to be more common in
certain racial groups but again we do not yet know why.
How is FSGS treated?
Normally the first sign of FSGS is nephrotic syndrome, where protein
is continuously lost in the urine. Your child will start with the
standard treatment for nephrotic syndrome, which is steroid medicine.
of FSGS do not respond to steroids, so are called steroid resistant. In
those cases, we try immunosuppressive medicines that damp down the
immune system. Unfortunately a large proportion of FSGS does not respond
to this kind of medicines.
Whether your child is taking steroids or immunosuppressive medicines,
you may need to postpone some of your child’s immunisations while
taking the medicines. You should also report to your family doctor (GP)
if your child comes into contact with chicken pox unless he or she has
already had it. Other precautions are included in our medicines
We also use a group of medicines called ACE (angiotensin converting enzyme) inhibitors and ARBs (angiotensin receptor blockers) to reduce
the protein loss and blood pressure. Diuretics (water tablets)
are also prescribed to reduce the puffiness.
It is important that the amount of protein lost in your child’s
urine is monitored closely. We may ask you to do these measurements
every day at home, using an dipstick. We will explain how to do this
before you go home. You will need to record these measurements alongside
details of your child’s steroid dose and any other medicines for each
day. You should bring them to each clinic appointment, as they are a
good indicator of how treatment is working.
Diet also plays a part in treating FSGS. We may ask you to reduce
the amount of salt you use at home. Our dietitian will explain exactly
what you need to do before you go home, and will be available for advice
What is the outlook for children with FSGS?
FSGS is a chronic condition. Your child’s health may improve for a
while, but many children do not respond very well to the treatment. In
others who respond the symptoms might come back. If this happens, he or
she will have to start taking the steroid or immunosuppressive medicines
Over time, more areas of the glomeruli become scarred, which
affects the child’s overall kidney function. FSGS may eventually
progress to irreversible kidney failure, although this could take many
In our experience of caring for children with FSGS at GOSH, three
in 100 children died and a quarter of patients had irreversible kidney
failure requiring kidney transplantation having been followed up for ten
Once your child’s kidney function has dropped to a level where it is
affecting his or her daily life, we will discuss dialysis and
transplantation with you. This is called renal replacement therapy (RRT)
and aims to keep your child well until a transplant is possible. There
is unfortunately a risk that the disease will come back in the