Nephrotic syndrome

Swelling in the body

Children with nephrotic syndrome have swelling or puffiness in different parts of their body – this is called oedema. The oedema is normally around the eyes in the morning, and in the legs and feet later in the day. After a while there may be swelling throughout the day. Boys may also have oedema in the scrotum.

It is pitting oedema - when the affected area is gently pushed, there is a small dent for a few moments.

Why the oedema happens

In nephrotic syndrome, the swelling happens because there is too much fluid in the body’s soft tissues.

This is caused by the kidneys leaking a lot of protein, which is normally in blood, into urine. When there is more protein in the urine than normal, this is called proteinuria. You cannot usually see the protein, but if there is a lot urine may look frothy. Your doctor can find proteinuria on a urine test.

If there is enough protein in the urine to cause nephrotic syndrome, this is called nephrotic-range 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 blood and the body’s soft tissues. When there is not enough albumin in the blood, fluid stays in the soft tissues.

Rare symptoms and signs

Swelling in the tummy and breathlessness

• A few children get a large swelling in their abdomen (tummy area). This is called ascites. It happens when fluid builds up in the area around the organs in the abdomen – the peritoneal cavity.
• A very small number of children feel breathless. This happens when fluid builds up around their lungs.

Other rare symptoms

A few children with nephrotic syndrome may also:

• feel tired, have low energy or have difficulty concentrating
• have a decreased appetite (not want to eat)
• have nausea (feel sick) or vomit (be sick), or have diarrhoea
• have pain in their abdomen (tummy).

Complications

Some children have complications – health problems that happen because of the nephrotic syndrome or its treatment. These are more likely to happen if the nephrotic syndrome lasts a long time – but even then, complications are very rare.

Risk of infections

Nephrotic syndrome is treated with steroid medicines, which make the immune system less active. This means it is more likely for children to get infections.

Acute kidney injury

Rarely, the kidneys stop working as well as they should – 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.

Some children with AKI get better after a few weeks, and some need to take medicines or have more intensive treatment.

Other complications

If your child has any of the below, seek medical advice:

• severe pain in the tummy or a fever (temperature above 38°C) – if your child sweats more than usual /or is shivery – this may be a sign of an infection called peritonitis
• swollen, red or painful leg – this may be a sign of a blood clot, when blood clumps together
• feeling more tired than usual, having sleep disturbances such as difficulty getting to sleep, becoming more forgetful or gaining weight – this may be a sign of low levels of thyroid hormone, a chemical in the body.

Immune system

Studies show that different types of nephrotic syndrome are linked to the immune system, which normally protects the body against disease and infection. Many germs – including bacteria and viruses – can make us sick if they get into the body. The immune system can kill these germs. However, if the immune system is not working properly, it can start to cause problems. In nephrotic syndrome, the immune system can interfere with the tiny filters in the kidneys, the glomeruli.

Will it affect other family members?

It is very rare for nephrotic syndrome to run in families. If one of your children has nephrotic syndrome, it is not likely that another of your children or another family member will get it. However, a few types may run in families.

Types and causes

There are different types of nephrotic syndrome, which depend on whether they can be treated by steroids. It is often not possible to find out which type your child has until after they have taken a course of steroids. Some causes of nephrotic syndrome can only be diagnosed (identified) in a kidney biopsy in which a tiny piece of one kidney is removed from the body with a needle and examined under special microscopes.

• About 9 in 10 children with nephrotic syndrome will have a type that can be treated with steroids – this is called steroid-sensitive nephrotic syndrome (SSNS) or minimal change nephrotic syndrome (MCNS).
• In some children the nephrotic syndrome keeps coming back, even after successful treatment with steroids – this is called frequently relapsing nephrotic syndrome.
• A few children (about 1 in 10) have a type that cannot be treated by steroids alone – this is called steroidresistant nephrotic syndrome (SRNS) because it is “resistant” (does not respond) to steroid treatment. Focal segmental glomerulosclerosis (FSGS) and IgM nephropathy are causes of steroid-resistant nephrotic syndrome.
• A small number of children have nephrotic syndrome because of another condition or infection that affects the kidneys.
• Occasionally, babies are born with congenital nephrotic syndrome. These babies may have serious damage to their kidneys and will usually need intensive treatment.

Your doctor can diagnose nephrotic syndrome by doing a physical examination and asking about the symptoms. Your child will need one or more urine tests, and may need other tests, such as blood tests or imaging tests.

Urine tests

You or a nurse will collect some of your child’s urine in a small, clean container for a urine test.

A dipstick, a strip with chemical pads that can change colour, is dipped into the urine. It can test for protein. Some dipsticks can also test for other substances, such as blood and sugar.

The urine sample may also be sent to a laboratory for more testing.

Some children will need more than one urine test.

Blood tests

A small amount of blood will be taken from a vein with a needle and syringe for a blood test. The blood test results can give the doctor more information, including:

• the level of protein in the blood
• information about the immune system
• how well the kidneys are working – this is called the kidney function
• the number of types of blood cells.

Imaging tests

Some children need imaging tests (scans). These use special equipment to get images (pictures) of the inside of their body.

• Ultrasound scan – looks at the shape and size of kidneys and other parts of the urinary system.  A small handheld device is moved around your child’s skin and uses sound waves to create an image on a screen.  
• Chest X-ray – for children with breathing problems, this test checks for any fluid (liquid) around the lungs. Your child sits or lies still for a few seconds while a machine takes X-ray images.

Occasionally, other imaging tests are needed.

Kidney biopsy

A kidney biopsy is not usually needed, but your doctor may recommend one to find out if there is damage is in the kidney. This is especially important if your child has relapses, as some medicines that are used to treat the nephrotic syndrome may harm the kidneys.

A tiny sample of a kidney is removed from the body with a needle – special medicines are used so your child will not feel any pain or can sleep through the procedure. The sample is sent to laboratory where it is looked at under microscopes.

When your child first develops nephrotic syndrome, he or she probably needs to stay in hospital for a few days to be carefully monitored.

Your child will probably be in a paediatric unit, a special area of your hospital for children. He or she will be looked after by a paediatrician, a children’s doctor.

A team of healthcare professionals will monitor your child to:

• check the kidney function (how well the kidneys are working)
• measure how much your child is drinking and how much urine he or she is passing
• test the urine with a dipstick
• check the blood pressure
• weigh him or her.

Steroids

The first treatment for nephrotic syndrome is a steroid medicine called prednisolone.

Steroids are made in the body, but can also be made as medicines. They suppress the immune system, or make it less active.

Giving medicine

Your doctor will let you know how often and for how long to give prednisolone. He or she will work out the amount of medicine (dose) that is right for your child – this will be shown on the medicine label.

Prednisolone is available as tablets and solution. Children who are unable to take medicines by mouth may be given a similar medicine called methylprednisolone, which is injected using a needle.

Vaccines

It is important that your child has the vaccines (immunisations) that he or she needs to reduce the risk of some diseases. Speak with your doctor about these – some vaccines are not safe to give while a child is taking steroids or immunosuppressants.

It is important that your child has the flu vaccine each year. The live attenuated influenza vaccine should not be given to children who are receiving high dose corticosteroids.

Infections

Children taking steroids are more likely to get infections. Speak with your doctor or nurse, and your child’s teacher or daycare manager, about how you can help prevent infection.

Seek medical advice straight away if your child:

• has been in contact with someone who has chicken pox (if they have not had this illness before) or measles (if they have not had the MMR vaccine, which protects against measles, mumps and rubella); 
• or, is unwell and you are worried about an infection.

If your child does get an infection, he or she may need to take an antibiotic medicine, which kills the germs that cause infection. Your child must take the medicine for the number of days that the doctor has told you, or until all of the medicine has been taken.

Side-effects

We use medicines to help children get better, but sometimes they have side-effects.

Seek medical advice straight away if your child:

• has fever (temperature above 38°C), with a sore throat or a cough
• has a rash, unusual bleeding that is difficult to stop, or severe bruising
• has bad stomach pain or repeated vomiting (being sick)

Other side-effects

Other side-effects that affect some children are below – speak with your doctor or nurse if you are concerned or need more support:

• irritation to the lining of the stomach – your doctor may give your child some medicine to treat this
• behavioural problems – you may find that your child is more likely to have tantrums, be moody, feel depressed, have difficulty sleeping or have nightmares
• weight gain and larger appetite – you can help by making sure your child has lots of physical activity and eats fruits, vegetables and low-calorie food, rather than food that is high in calories (such as cakes, biscuits, sweets and crisps) and by reducing the portion size
• high blood pressure (hypertension) – if this happens, your child’s blood pressure will need to be controlled so it is in a healthy range.

There may, sometimes, be other side-effects that are not listed above. If you notice anything unusual and are concerned, contact your doctor.

No-added salt diet

Eating too much salt can make the oedema worse and increase the risk of developing hypertension (high blood pressure), especially while on steroids. Your child should avoid eating or drinking lots of salted nuts, crisps, crackers, soft drinks, fast food meals, takeaways and processed foods (meals that are preprepared, including soups) – these often have more salt than we think.

Do not add extra salt to meals that you cook or at the dining table.

A paediatric dietitian at the hospital may be able to give you support.

Prevent or treating infections – antibiotics

Reducing swelling in the body – diuretics

Very occasionally, children need to take diuretics, medicines that help reduce swelling in the body (oedema). Diuretics work on the kidneys to increase the amount of water and salt they remove from the body in urine. Your doctor will examine your child for oedema and measure your child’s weight while they are taking diuretics, to check how well the medicine is working.

Common diuretics are: furosemide, spironolactone and metolazone. Other diuretics that may be used are: amiloride, bendroflumethiazide and chlorothiazide.

Your child will need to eat less salt at the same time as taking these medicines.

Questions to ask the doctor or nurse

• What treatment will my child need?
• How will this help my child?
• How can I help my child prepare for procedures and treatments?
• What happens next if the first treatment does not work for my child?
• How will I know if we need to go back to the hospital or see the doctor?
• Will the nephrotic syndrome come back? How will I know?

Most children with nephrotic syndrome will start to get better after taking steroids for 1 to 2 weeks. In about 9 in 10 children, the nephrotic syndrome will have responded to the steroids within 4 weeks.

Testing urine at home

You will need to test your child’s urine for protein every morning – while your child is on steroids, and then for at least 6 months. Your doctor will let you know how often to test the urine and when you can stop.

When to do the urine tests

Some children, even when they do not have nephrotic syndrome or another kidney problem, have a very small amount of protein in their urine after standing or sitting upright for a few hours. For this reason, it is best to get a sample of your child’s first morning urine, the urine passed when they first go to the toilet in the morning.

How to do the urine tests

You will be given dipsticks – these are strips with chemical pads that change colour depending on what substances are in the urine. A nurse will show you how to use them.

Older children can urinate over the dipstick. For younger children, you can get a sample of urine from a potty.

Recording the results

Read the result, using the instructions included in the package. Write in a diary, including:

• the date
• the urine test result
• any medicines taken (e.g. steroid and dose, or amount)
• any comments about your child’s health (e.g. feeling unwell)

Bring the diary to your next clinic visit.

Remission

If the urine dipstick will show either “trace” or “negative” for protein for three days in a row, the nephrotic syndrome has gone into remission. The kidneys have stopped leaking protein.

Relapse

If the urine dipstick shows either 3+ or 4+ protein for three days in a row, the nephrotic syndrome has relapsed. The kidneys have started leaking protein again.

More than half of children with nephrotic syndrome have at least one relapse. By regularly testing your child’s urine, you can quickly detect a relapse. Your child can start treatment, 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.

Follow-up appointments

Your child will need to have medical assessments in the clinic. It is important that you bring your child to these follow-up appointments even if they seem well. You will also have the opportunity to ask any questions. Remember to bring your records of the home urine testing.

At these appointments, your child may have:

• their height and weight checked
• a physical examination
• urine tests – to check for protein and other substances in their urine
• blood tests – to check for the amount of protein and other substances in their blood; blood tests may also be used to check their kidney function (how well their kidneys are working)
• blood pressure measurements.

Relapses

About half of children with SSNS will have at least one relapse – when the nephrotic syndrome comes. Many two or three relapses. Often, these relapses can be successfully treated with another course of steroids.

In most children, the SSNS tends to relapse less often as they grow into their teenage years. It is rare that SSNS continues to relapse in adulthood.

Frequent relapses

A few children have frequent relapses – when the nephrotic syndrome keeps coming back. This is called frequently relapsing nephrotic syndrome

If this happens, your doctor will consider the best treatment for your child. For example, they may take a small amount of the steroid prednisolone every other day to prevent relapses. If that does not work, they may need to take other, stronger medicines.

Referral to a paediatric nephrologist

Some children are referred to a children’s kidney specialist called a paediatric nephrologist. These children may need more tests such as a kidney biopsy or more specialised treatment.

This may happen if:

• your child has frequently relapsing nephrotic syndrome
• your child’s nephrotic syndrome does not get better within 4 weeks of taking steroids, or your doctor thinks that your child has a rarer type of nephrotic syndrome, for example, caused by the conditions focal segmental glomerulosclerosis or IgM nephropathy.

Impact on your child and family

Children who have nephrotic syndrome can usually do the things that other children their age do, including during relapses. After a hospital stay, they should be able to continue going to school or nursery. They can play with other children and stay active.

Living healthily

Your child can help protect his or her kidneys by leading a healthy lifestyle through their child and adult years. This includes:

• eating a healthy diet – with at least five servings of fruit and vegetables a day, taking care not to eat too much salt, sugar and fats (especially saturated fats)
• getting plenty of exercise
• not smoking.

Getting support

This can be a difficult and stressful experience for your child and the whole family, including other children.

Further information

This is the end of the information on steroid-sensitive nephrotic syndrome. If you would like to read more about other kidney conditions, tests and diagnosis, treatment or supporting information, go to our home page, www.infokid.org.uk.

© BAPN and Kidney Care UK 2013-2022, all rights reserved.

For details on any sources of information used in this topic, please contact us through the contact us form on our website www.infoKID.org.uk.

We take great care to make sure that the information in this leaflet is correct and up-to-date. However, it is important that you ask the advice of your child’s doctor or nurse if you are not sure about something. This information is intended for use in the United Kingdom, and may not apply to other countries. The British Association of Paediatric Nephrology (BAPN), Kidney Care UK and the contributors and editors cannot be held responsible for the accuracy of information, omissions of information, or any actions that may be taken as a consequence of reading this information.