FSGS and IgM Nephropathy

Common symptoms and signs

The main symptoms and signs for FSGS and IgM nephropathy are similar to those in other types of nephrotic syndrome.

Swelling in the body

Children 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 of the scrotum. It is pitting oedema. This means that when the affected area is gently pushed, there is a small dent for a few moments.

In FSGS and IgM nephropathy, 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 the bloodstream, into the urine. An abnormal amount of protein in the urine is proteinuria. You cannot usually see the protein. Your child’s doctor can find proteinuria on a urine test.

A lot of the protein 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, and when there is not enough albumin in the blood, fluid stays in the soft tissues.

Problems urinating

Some children urinate less often or smaller amounts.

Blood in the urine

Some children also have haematuria (blood in their urine), which happens when red blood cells leak through the kidney’s filters into the urine. Sometimes you cannot see the blood, but if there is a lot, the urine may be coloured red or dark brown (like blackcurrant squash or a cola drink).

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 in the area around their lungs.

Other rare symptoms

The symptoms below are occasionally found in children with FSGS or IgM nephropathy:

• tiredness, low energy or difficulty concentrating
• decreased appetite (not want to eat)
• nausea (feeling sick), vomiting (being sick), or diarrhoea
• pain in the abdomen (tummy)
• headaches that keep coming back or that do not go away
• pain, stiffness or swelling of the joints.

Complications

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

Risk of infections

• Children with FSGS and IgM nephropathy are treated with medicines that suppress, or damp down, their immune system, which normally protects them from infections. They are therefore more likely to get infections such as the common cold or a urinary tract infection.
• If your child is unwell and you are worried about an infection, contact your doctor straight away.

Other complications

If your child has any of the below contact your doctor:

• severe pain in his or tummy and/or a fever (temperature above 38°C) – this may be a sign of an infection called peritonitis
• swollen, red or painful leg – this may be a sign of a blood clot 
• headaches, vomiting or blurred (fuzzy) vision – this may be a sign of hypertension (high blood pressure)
• 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

High levels of fat in the blood

Rarely, children with FSGS and IgM nephropathy have too much of some fats in their blood – even when they eat a healthy diet and are active. This is more likely in children who have proteinuria for long periods of time.

Eating a healthy diet and being active usually helps keep these fats at a healthy level. But in nephrotic syndrome, there is a lower level of some proteins, especially albumin, in the blood because they are leaked into urine. This causes the levels of fats to increase.

When the kidneys stop working suddenly

In serious cases, the kidneys stop working as well as they should, over a short period of time – this is called acute kidney injury (AKI). Some children get better after a few weeks, and some need to take medicines or have more intensive treatment. 

FSGS and IgM nephropathy lead to nephrotic syndrome – the kidneys leak a lot of protein into urine. This leads to a drop in the levels of protein in the blood, which causes swelling in the body (oedema). 

Who gets FSGS and IgM nephropathy?

FSGS and IgM nephropathy is rare. About 1 in 50,000 children get nephrotic syndrome each year, but only about 1 in 10 of these cases are due to these conditions.

Some children who have had frequently relapsing nephrotic syndrome can develop FSGS or IgM nephropathy after many years. 

It is not always known why some children get FSGS or IgM nephropathy. It is often considered to be linked to a problem with the immune system, which is the body’s way of protecting itself from infection.

The 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.

Other causes

Some cases of FSGS and IgM nephropathy are due to other reasons, though these are more rare.

• Genetic mutation – some children have a genetic mutation that affects the structure of part of the glomerulus in the kidney, which causes the protein leak. Genetic mutations are problems in the genes (which are in each of our body’s living cells), which are passed on by the parents. Your doctor will talk to you about this, and may arrange for a genetic test to be done.

Will it affect other family members?

It is very rare for FSGS, and even rarer for IgM nephropathy, to run in families. Your child’s doctor will ask about any family history of these conditions, and it is usual to arrange for siblings to have a urine test to check for protein.

Diagnosing nephrotic syndrome

Your doctor may have diagnosed (identified) nephrotic syndrome before suspecting FSGS or IgM nephropathy. To find out how nephrotic syndrome is first diagnosed, go to Nephrotic syndrome – steroid-sensitive: Tests and diagnosis. 

When FSGS or IgM nephropathy is suspected

Your doctor may suspect FSGS or IgM nephropathy if your child has symptoms or signs of nephrotic syndrome and: 

• has visible blood in his or her urine (haematuria) – the urine may be coloured red or dark brown (like blackcurrant squash or a cola drink)
• is urinating less often or smaller amounts
• has high blood pressure (hypertension)
• blood tests show that the kidneys are not working properly
• has a disease in another part of his or her body, such as the skin or joints of the arms and legs
• is a baby, infant or teenager, or
• has nephrotic syndrome that keeps coming back (frequently relapsing) in spite of taking extra medicines.

Tests for FSGS or IgM nephropathy 

Your child will need further tests to find out more about his or her health, the effect of any medicines and to make a diagnosis. These tests may include: 

• an examination – for example, to check for early signs of oedema (swelling of the body)
• blood pressure measurements – to check for hypertension
• urine tests – to check the urine for protein and other substances such as blood cells 
• blood tests – to check the blood for levels of protein, how well the kidneys are working, and the levels of medicines your child is taking
• a genetic test and genetic counselling – to check if your child has a faulty gene (genetic mutation). Genetic testing usually involves getting a sample of blood or body tissue, which can be checked for a specific gene. Genetic counselling is a service that can give you information and guidance about conditions caused by genetic mutations.
• kidney biopsy 
• imaging tests (scans).

Kidney biopsy

A kidney biopsy can usually confirm whether a child has FSGS or IgM nephropathy or any other abnormalities. It can also give more information about how much damage there is in the kidney.

A tiny piece of one kidney is removed from the body with a needle – special medicines are used so your child does not feel any pain or can sleep through the procedure. The sample is sent to a laboratory where it is looked at under microscopes. It can also be checked for proteins related to the immune system. 

Imaging tests

Imaging tests (scans) use special equipment to get images (pictures) of the inside of your child’s 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.

In FSGS or IgM nephropathy, the symptoms of nephrotic syndrome usually cannot be treated by steroids alone. Your child may need to take stronger immunosuppressant medicines, which reduce the effect of the immune system on the kidneys. 

Some children need treatment for any complications – to prevent or treat infections, reduce oedema (swelling in the body) or reduce the levels of fats in the blood.

Where will my child be treated?

Once your child is diagnosed with FSGS or IgM nephropathy – usually after a kidney biopsy – your doctor will decide on the best treatment. 

Steroids and immunosuppressants

Steroids

The first treatment for nephrotic syndrome is a steroid medicine, usually prednisolone. Steroids are chemicals that are made naturally in the body, but can also be made as medicines. They suppress the immune system, or make it less active. Your doctor will give you more information about how and when your child should take the medicine.

Immunosuppressants

However, children whose nephrotic syndrome is caused by FSGS or IgM nephropathy may need stronger medicines that are known as immunosuppressants. There are different types of immunosuppressants, and your child may need to take more than one of these medicines, sometimes in combination, to try to treat the condition. They include:

• ciclosporin – also known as cyclosporin
• tacrolimus
• mycophenolate mofetil – also called MMF

More rarely, the medicines include:

• rituximab
• vincristine
• cyclophosphamide
• chlorambucil 

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. 

Infections

Children taking these medicines 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. 

Contact your doctor 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 effects we do not want – side-effects. Contact your doctor straight away if your child has any of the following while on steroid medicines:

• fever (temperature above 38°C), with a sore throat or a cough
• a rash or severe bruising
• bad stomach pain or repeated vomiting – sometimes steroids can cause ulcers in the stomach.

Risk to kidneys

Although we use these medicines to try to treat nephrotic syndrome, some, especially tacrolimus and ciclosporin, may have an effect on kidney function (how well the kidneys work). Your child’s healthcare team will closely monitor the levels of these medicines in regular blood tests. 

Changes to eating and drinking

Your child may need to make temporary changes to what he or she eats. For example, he or she may need to eat less salt while they have oedema or are taking steroids. This is because higher levels of salt in the body cause the kidneys to keep more water. 

Your doctor, nurse or dietitian will help you and your child make these changes. 

Treating complications

Some children need further treatment for complications, such as:

• preventing or treating infections, such as peritonitis, which affects the area inside their abdomen (tummy) – your child may need to take antibiotics, medicines that kill bacteria 
• reducing oedema 
• reducing the level of fats in their blood.
• treating low levels of thyroid hormone.

Managing reduced kidney function

For some children, the kidneys do not work as well as normal during this illness – they have reduced kidney function. Most children do not need any special treatment, but will need long term follow-up because kidney function may slowly get worse over years.

A small number of children with FSGS, and a very small number of children with IgM nephropathy will have more serious kidney problems and will need further treatment. This may include dialysis, which uses special equipment to ‘clean’ the blood, removing waste products and extra water and salts, and sometimes adding important salts. 

Questions to ask the doctor or nurse

• What treatment will my child need?
• How will the treatment help my child?
• How long will my child be in hospital?
• How can I help my child prepare for procedures and treatments?
• If the first treatment does not work in my child, what happens next?
• How will I know if we need to go back to the hospital or see the doctor?
• Will the conditions come back? How will I know?

Testing urine at home

While your child is on steroids or immunosuppressants, you will need to test your child’s urine for protein every morning. 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. This is the urine that your child passes when they first wake up 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. 

Put the dipstick in the urine sample, remove it and read the result. Use the instructions included in the package.

Record the result in a diary – make sure you include:

• 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 shows either “trace” or no protein for three days in a row, and the swelling goes down, this means that the condition has gone into remission. 

Most children go into remission within 6 months of starting the immunosuppressants. Some have a lower level of proteinuria – this is called partial remission.

Relapse

If the urine dipstick shows either 3+ or 4+ protein for three days in a row, this means that there has been a relapse. The kidneys have started leaking protein again, and the symptoms may come back.

Daily testing of your child’s urine will allow you to quickly detect a relapse. Your child will be able to start treatment, often without needing to go into hospital. If the urine tests are not used and your child has a relapse, they may become unwell and develop oedema, and are more likely to need to go into hospital.

Measuring blood pressure at home

You may be asked to measure your child’s blood pressure, using a blood pressure monitor that you can get from your doctor or a pharmacy.

More about measuring blood pressure at home

Your healthcare team will speak with you and your family about any long-term effects your child might have with FSGS and IgM nephropathy. Your child will have follow-up appointments and you may need to monitor him or her at home.

Some children fully recover from these conditions – when the symptoms go away, this is called remission. Others may experience relapses – when the kidneys start leaking protein again and the symptoms reappear. These may be triggered by an infection, such as a cold. 

A few children have long-term problems with their kidneys. 

Follow-up appointments

Your child will need to have follow-up appointments at the hospital or clinic to check for any health problems.

It is important to go to these appointments, even if your child seems well – remember to bring the results from your home urine testing. You will also have the opportunity to ask any questions. At these appointments, your child may have:

• his or her height and weight checked
• a physical examination
• urine tests – to check for blood, protein and other substances in his or her urine
• blood tests – to check for the amount of protein and other substances in his or her blood, and measure his or her kidney function 
• his or her blood pressure measured.

Long-term effects

Remission and partial remission

Most children with FSGS and IgM nephropathy will go into remission within 6 months of starting the immunosuppressant medicines. Of those children who do not go into remission, some will have less proteinuria – this is called partial remission.  

Frequent relapses

Most children have at least one relapse. A few children have frequent relapses – this is called frequently relapsing nephrotic syndrome – and may need further treatment.

Long-term problems

Some children with these conditions may develop a low level of proteinuria (an abnormal amount of protein in the urine). 

Some children may have hypertension (high blood pressure), especially later in life.

A few children develop long-term problems with their kidneys – this may be due to the problems with the condition or be a result of the treatment, such as some of the immunosuppressants that are needed. The kidneys stop working as well as they should. This is called chronic kidney disease (CKD). A very small number of children need dialysis and transplantation as a result of FSGS. FSGS may recur (come back) in the transplanted kidney. Your healthcare team will talk to you about this.

If your child has CKD, you will learn more over time about how to help manage the condition, and what to expect. 

What you can do

After treatment

Children who have been successfully treated for FSGS or IgM nephropathy can usually do the things that other children their age do. 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 throughout 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.

Further 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 FSGS and IgM nephropathy. If you would like to read more about other kidney conditions, tests and diagnosis, treatment or supporting information, you can find a list of topics covered on the infoKID website at 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.