Nephrotic syndrome in children
The kidneys of people with nephrotic syndrome don't work properly, causing large amounts of protein to leak into their urine.
It can affect people of any age, but is often first seen in children aged between two and five years.
The loss of protein can cause a range of problems, including swelling of body tissues and a greater chance of catching infections.
Symptoms can usually be controlled by medication, with steroids often used.
Children with nephrotic syndrome have times when their symptoms are under control (remission), followed by times when symptoms return (relapses). Most will relapse less frequently as they get older, eventually "growing out of it" by their late teens.
Most children with nephrotic syndrome respond well to steroids and aren't at risk of kidney failure.
However, a small number of children have congenital (inherited) nephrotic syndrome and usually do less well. They may eventually have kidney failure and need a kidney transplant.
What problems can it cause?
Some of the main symptoms associated with nephrotic syndrome are:
The low level of protein in the blood reduces the movement of water from surrounding tissues back into the blood vessels, leading to swelling (oedema).
Swelling is usually first noticed around the eyes, then around the lower legs and rest of the body.
Antibodies are a specialised group of proteins in the blood that help fight infection. When these are lost, children are much more likely to get infections and frequently experience fatigue, poor appetite and weakness.
Occasionally, the high levels of protein being passed into the urine can cause it to become "frothy". Some children with nephrotic syndrome may also pass less urine than usual during relapses.
Important proteins that help prevent the blood from clotting can be passed out in the urine of children with nephrotic syndrome. This can increase their risk of potentially serious blood clots.
Causes of nephrotic syndrome
Most children with nephrotic syndrome have what doctors call "minimal change disease". This means their kidneys will appear normal or nearly normal if a tissue sample was studied under a microscope. The cause of minimal change disease is unknown.
Sometimes, nephrotic syndrome can occur as a result of a kidney problem or another condition, such as:
glomerulosclerosis (when the inside of the kidney becomes scarred)
glomerulonephritis (inflammation inside the kidney)
an infection such as HIV, hepatitis or syphilis
sickle cell anaemia
certain types of cancer, such as leukaemia, multiple myeloma orlymphoma
These problems tend to be more common in adults with nephrotic syndrome.
Congenital nephrotic syndrome is usually caused by an inherited faulty gene. For the condition to be passed on to a child, both parents must have a healthy copy of the gene and a faulty one. This means they don’t have nephrotic syndrome themselves, but there is a one in four chance that any children they have will develop the condition.
Who is affected?
Nephrotic syndrome can affect people of any age, but is commonly seen in young children. It affects more boys than girls. The condition is usually first diagnosed in children aged between two and five.
Nephrotic syndrome is uncommon. Only about one in every 50,000 children are diagnosed with the condition each year. It tends to be more common in families with a history of allergies or with an Asian background, although it is unclear why.
How is it diagnosed?
Nephrotic syndrome can usually be diagnosed after dipping a chemically sensitive strip into a urine sample. If there are large amounts of protein in a person's urine, the strip will change colour.
A blood test showing low levels of protein will confirm the diagnosis.
In some cases, when initial treatment doesn't work, your child may need to have a kidney biopsy. This is when a very small sample of kidney tissue is removed using a needle, so it can be studied under a microscope.
Managing nephrotic syndrome
The main treatment for nephrotic syndrome is steroids, but additional treatments may also be used if a child develops significant side effects.
Most children will have relapses and will need to take steroids when these occur.
Your child may be referred to a childhood kidney specialist (paediatric nephrologist) for tests and specialist treatment.
When they are first diagnosed, your child will normally be prescribed at least a four week course of the steroid medicine prednisolone. This will need to be taken every day, followed by another four weeks where the medication is taken every other day. This stops protein leaking from your child's kidneys into their urine.
When prednisolone is prescribed for short periods, there are usually no serious or long-lasting side effects, although some children may experience increased appetite, weight gain, swollen cheeks and mood changes.
Most children respond well to treatment with prednisolone, with the protein often disappearing from their urine and the swelling going down within a few weeks. This period is known as remission.
Diuretics, or "water tablets", may also be given to help reduce the fluid build-up. They work by increasing the amount of urine produced.
Penicillin is an antibiotic and may be prescribed during relapses to reduce the chances of an infection.
To prevent further water retention and oedema, you may be advised to reduce the amount of salt in your child's diet. This means avoiding processed foods and not adding salt to what you eat.
Children with nephrotic syndrome are advised to have thepneumococcal vaccine. Some children may also be recommended the varicella (chickenpox) vaccination between relapses.
Live vaccines (such as MMR, chickenpox and BCG) should not be given while your child is taking medication to control their symptoms.
If your child's remission cannot be maintained with steroids, or if they experience significant side effects, other medications may be used alongside or in place of steroids, to help control their symptoms and reduce the risk of relapses.
Additional medications that may be used include levamisole, cyclophosphamide, ciclosporin and tacrolimus, mycophenolate and rituximab.
Most of the protein lost in nephrotic syndrome is albumin. If your child's symptoms are severe, they may be admitted to hospital to receive albumin infusions.
Albumin is slowly added to the blood over a few hours, through a thin plastic tube called a cannula that is inserted into one of the veins in their arm.
Caring for your child at home
If your child has been diagnosed with nephrotic syndrome, you will need to monitor their condition on a daily basis to check for signs of relapses.
You will need to use a dipstick to test your child's urine for protein the first time they urinate each day. The result for each day will need to be written down in a diary for your doctor to review during your outpatient appointments.
You should also note down the dose of any medication they are taking and any other comments, such as whether your child is feeling unwell.
If the dipstick shows +++ or more of protein in the urine for three days in a row, this means your child is having a relapse. If this happens, you either need to follow the advice given about starting steroids or contact your doctor.
You should seek immediate medical advice if:
your child has come into contact with someone who has chickenpox or measles
your child is puffy, unwell or has a fever
your child has diarrhoea and is vomiting
Treating congenital nephrotic syndrome
If your child has congenital nephrotic syndrome, they will need frequent albumin infusions to help them grow and develop normally. This will often require a stay in hospital.
Sometimes, parents can be trained to administer the treatment at home and your child will be regularly reviewed in a clinic, where their blood pressure, growth, weight, kidney function and bone health will be monitored.
It can be difficult for parents to decide which option is best, so you should talk to your doctor about the pros and cons of hospital-based and home-based treatment.
Dialysis and kidney transplants
In some cases, your doctor may recommend surgery to remove one or both of your child's kidneys. This will stop proteins being lost in your child's urine and will reduce their risk of potentially serious problems, such as blood clots.
This means they will be dependent on dialysis (a machine that replicates kidney function) from an early age until they can receive a kidney transplant.
A person only needs one kidney to survive. Therefore, unlike most other types of organ donation, a living person can donate a kidney. Ideally, this should be a close relative.
What do our kidneys do?
The kidneys filter waste products from the blood before turning it to urine. This video explains in detail how the kidneys function.
Media last reviewed: 15/11/2013
Next review due: 15/11/2015
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