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.
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.
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 or lymphoma
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.
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.
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.
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: