In nephrotic syndrome, the kidneys leak too much protein into urine, leading to a drop in the levels of protein in the blood. This causes swelling in the body, especially in the face, legs and feet (oedema). Nephrotic syndrome is usually treated with a steroid medicine called prednisolone, and in most children the symptoms go away after a few weeks or a bit longer.
Many children have at least one relapse – when the symptoms come back after treatment, and they need to take steroid medicines again. Some children have relapses that happen very frequently. This is called frequently relapsing nephrotic syndrome. These children may need further treatment during their relapses, such as stronger medicines.
About nephrotic syndrome
When children first develop nephrotic syndrome, they are usually admitted to hospital for monitoring and treatment. In many children, the steroid successfully treats the condition within a few weeks or a bit longer. Their kidneys stop leaking protein and their swelling goes down.
- This is called steroid-sensitive nephrotic syndrome (SSNS) because the nephrotic syndrome is ‘sensitive to’ (can be treated by) steroids.
- It may also be called minimal change nephrotic syndrome because there is no or very little change in the way the kidneys look.
In most children, the nephrotic syndrome comes back within a year – this is a relapse.
Frequently relapsing nephrotic syndrome
About half of children with SSNS have frequent relapses. This means that although the nephrotic syndrome gets better with steroids, it keeps coming back in a short space of time. It is called frequently relapsing nephrotic syndrome if this happens:
- two or more times in 6 months, or
- four or more times in one year.
Children with frequent relapses may continue to have them throughout childhood, though they tend to relapse less often as they grow into their teenage years. It is rare that SSNS continues to relapse in adulthood.
Monitoring for relapses
If your child has frequent relapses, you will need to test his or her urine for protein every morning. You will be given dipsticks – these are strips with chemical pads that change colour if there is protein in the urine. A nurse will show you how to use them.
Continue doing the urine tests even when your child is well, and keep a record of the results.
If the urine dipstick shows either 3+ or 4+ protein for three days in a row, the nephrotic syndrome has relapsed.
What happens next
By regularly testing your child’s urine, you can quickly detect a relapse and your child can start treatment with steroids quickly, often without needing to go into hospital. If the urine tests are not used and your child has a relapse, he or she may become unwell and develop oedema, and is more likely to need to go into hospital.
Causes
The main symptom of nephrotic syndrome is oedema – swelling or puffiness in the body, especially around the eyes and in the legs and feet. It happens when there is too much fluid (water) in the body’s soft tissues. This happens because the kidneys leak a lot of protein, which is normally in the blood, into urine.
When there is more protein in the urine than normal, this is called proteinuria. There are different types of protein in the blood. The most common type that is leaked is a type called albumin. Albumin helps keep fluid in the blood. Fluid moves between the bloodstream and the body’s soft tissues. When there is not enough albumin in the blood, fluid stays in the soft tissues.
However, if you detect a relapse with home urine testing and your child starts treatment soon after, he or she is less likely to develop oedema. If there is oedema, it will probably be less than the first time your child had nephrotic syndrome.
Complications
Complications – health problems that happen because of the nephrotic syndrome or treatment – are rare. They happen in a small number of children during the first episode of nephrotic syndrome or in relapses.
If your child has any of the below, especially in a relapse, contact your hospital doctor or seek medical advice:
- headaches, vomiting or blurred (fuzzy) vision – this may be a sign of hypertension (high blood pressure) – this may be a complication of taking steroids
- a large swelling of the abdomen (tummy). This is called ascites. It happens when fluid builds up in the area around the organs in the abdomen – the peritoneal cavity.
- feeling breathless – this can happen if fluid builds up in the area around their lungs
- severe pain in the tummy – which may be a sign of too little fluid in the blood supply to the bowels
- severe pain in the tummy and a fever (temperature above 38°C), and sometimes sweating more than usual or shivering – this may be a sign of an infection called peritonitis
- a swollen, red or painful leg – this may be a sign of a blood clot (when a clump of blood blocks a blood vessel).
Acute kidney injury
Rarely, the kidneys stop working as well as they should in relapses – this is called acute kidney injury (AKI). In nephrotic syndrome, this may happen when the body has a lower volume of blood than normal – this is called hypovolaemia. Many children with AKI get better after a few weeks, and some need to take medicines or have more intensive treatment.