What is steroid sensitive nephrotic syndrome (SSNS)?
Nephrotic syndrome is a rare kidney condition that causes too much protein to be lost in the urine and too much water to be retained in the body.
In most cases, nephrotic syndrome can be treated with steroids. It is then known as steroid sensitive nephrotic syndrome (SSNS).
However, for some people, steroids do not work. In those cases, the condition is known as steroid resistant nephrotic syndrome (SRNS).
In rare cases, steroids work at first and then stop working, so the diagnosis changes from SSNS to SRNS.
Nephrotic syndrome affects around 10,000 people in the UK a year. SSNS affects around nine in ten children with nephrotic syndrome and six in ten adults with nephrotic syndrome.
What are the signs and symptoms of SSNS?
Common symptoms of SRNS include:
- protein in the urine (proteinuria) – this is likely to only be seen under a microscope or when tested by dipping a specially treated paper strip into your urine (urine dipstick). However if there is a lot of protein, the urine may look frothy.
- swelling or puffiness (oedema) in different parts of the body, especially around the eyes and ankles. Swelling around the eyes tends to be worse first thing in the morning and improve as the day goes on whereas ankle swelling is usually worse in the evenings. The swelling is soft and puffy and leaves a dent if you press on it. There is no pain associated with the swelling. It is not an allergic reaction but is caused by the kidneys retaining too much water.
- increased risk of infection
- anaemia
- low blood pressure
What causes SSNS?
Nephrotic syndrome occurs when the tiny filters in the kidney (glomeruli) are damaged. This causes them to leak protein and retain excess water. Over time this can cause kidney damage.
Other substances can also be lost through the damaged filters, including antibodies that help prevent infections. Without these, people with SRNS are more vulnerable to illnesses and infections.
Hormones and vitamins can also be lost, which can lead to delayed growth in young children.
The exact cause of SSNS is not always known. It can occur after an illness or infection or as part of another condition such as membranous nephropathy. There is likely to be a genetic basis to at some cases but the precise details of this are not yet fully understood.
How is SSNS diagnosed?
Nephrotic syndrome is diagnosed by a urine test which will show very high levels of protein.
The exact type of nephrotic syndrome can be diagnosed by a kidney biopsy or by treatment with steroids. If the steroids work, the condition is known as steroid sensitive nephrotic syndrome (SSNS). If they do not work after four to six weeks, it is steroid resistant nephrotic syndrome (SRNS).
Genetic testing may also be offered.
Does SSNS affect other parts of the body?
During flare ups of SSNS (when swelling occurs) people are more at risk of infections or of developing blood clots, particularly in the veins of the legs (thrombosis).
Does SSNS run in families?
The precise details of any inheritance patterns in SSNS are still being investigated.
How is SSNS treated?
SSNS is treated with steroids (prednisolone). These are very effective in reducing the protein loss and reducing the swelling.
Around one in three people with SSNS only need one round of treatment and the condition never comes back. Other people will have multiple relapses. These are often triggered by an infection or a cold.
Repeated relapses may be treated with other medications including angiotensin‐converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) to help reduce proteinuria.
People with SSNS may be asked to regularly test their urine at home for signs of protein to check for any signs of early relapse.
Severe kidney damage and the need for dialysis or transplant is very rare.
Where can I get more information or support about SSNS?
For more information on SSNS including its diagnosis, symptoms and treatment, visit Nephrotic Syndrome Trust.
Publication date: 11/2023
Review date: 11/2026
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