FSGS and IgM nephropathy: tests, diagnosis and treatment

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. 

Read more about what happens in hospital

A team of healthcare professionals will:

  • check your child’s kidney function (how well his or her kidneys are working)
  • measure how much your child is drinking and how much urine he or she is passing
  • test your child’s urine with a dipstick
  • check your child’s blood pressure
  • weigh your child to help find out if he or she has too much or too little fluid in their body

Healthcare team

Your child’s healthcare team may include:

  • paediatrician – a children’s doctor
  • paediatric nephrologist – a doctor who treats children with kidney problems 
  • renal nurse – a nurse who cares for children with kidney problems
  • paediatric dietitian – a professional who advises what your child should eat and drink during different stages of their kidney condition 
  • renal social worker – a professional who supports you and your family, especially with any concerns about money, travel and housing related to looking after your child with kidney disease
  • renal psychologist – a healthcare professional who supports your child and family, especially with emotional stresses and strains from having or looking after a child with kidney disease
  • play specialist – a professional who uses dolls and other toys to help your child prepare for procedures, such as blood tests and dialysis

Steroids and immunosuppressants


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.

It is important that you continue giving the steroid to your child as your doctor has told you, even if your child is getting better. Stopping steroids suddenly can make your child very unwell, so your child should only stop taking steroid medicines on the advice of your doctor.


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 


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. 


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. 


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.

Read more about treating complications

Preventing or treating infection

Your child may be at higher risk of getting infections when he or she is being treated for nephrotic syndrome. This is because the medicines suppress the immune system, so it cannot work as effectively to fight germs, and the oedema lets germs grow more easily. One important infection is peritonitis, which affects the peritoneum, the area around the organs in the abdomen (tummy area).

Antibiotics are medicines that kill bacteria. Your child may need to take antibiotics to prevent or treat infection – this is often the medicine penicillin.

  • To prevent infections, you may need to give a small amount of antibiotic twice a day while your child has oedema.
  • If your child gets an infection, you may need to give a full course of this or another antibiotic to treat it.

It is important that you follow your doctor’s instructions about when and how much to give.

Medicines for Children – Penicillin V for prevention of pneumococcal infection

Medicines for Children – Penicillin V for bacterial infection

Medicines for Children website | General advice about antibiotics

Reducing oedema

Occasionally children with these conditions need to take diuretics. These medicines help reduce oedema by removing extra water and salt from the body, and by increasing the amount of urine that is passed. 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.

Controlling levels of fat in the blood

Some children need medicines to treat hyperlipidaemia, or high levels of fats, including cholesterol and triglycerides. Some children who have high levels of protein in their urine for a long time may be at risk of this. 

Some medicines include:

  • statins – which reduce the amount of cholesterol the body makes
  • fish oil supplements, such as MaxEPA – because some types of fish are thought to help reduce the level of fats

Low levels of thyroid hormone

The thyroid is a gland in the neck that makes thyroid hormone. This hormone (a chemical that is carried in the blood to send messages to other parts of the body) controls how the body uses energy. 

Some children with nephrotic syndrome have low levels of thyroid hormone in their body – this is called hypothyroidism (“hypo” means low or not enough). This causes many of the body’s functions to slow down. Some children with hypothyroidism may:

  • be more tired than usual or have sleep disturbances such as difficulty getting to sleep
  • become more forgetful
  • gain weight
  • have dry hair, skin and nails
  • have changes in mood (more sad than normal)
  • be constipated (difficulty doing a poo)
  • feel breathless
  • feel sensitive to cold
  • get cramps in their muscles, or feel weak.

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?