Nephrotic syndrome is not a specific disease but the name given to the set of problems that can arise if your kidneys become damaged. This page gives you basic information about the condition, including its causes, symptoms, diagnosis and treatment.
How does nephrotic syndrome develop?
One of the main jobs of your kidneys is to filter your blood. This allows you to pass your body's waste products, extra fluid and salts through your urine. The glomeruli are the parts of the kidney where this happens.
With healthy kidneys, proteins in your blood don't usually leak into the urine during the filtering process. But if the glomeruli become damaged, proteins such as albumin can leak into your urine along with the waste products. If too much protein leak out, that is known as nephrotic syndrome.
What causes nephrotic syndrome?
Nephrotic syndrome can be caused by diseases that affect the kidneys directly, as well as underlying diseases that affect the whole body.
Kidney diseases that commonly cause nephrotic syndrome include:
- minimal change disease — this causes a small change in the filters of the kidneys
- focal segmental glomerulosclerosis — this causes scar tissue to build up in the kidneys' filters
- membranous glomerulopathy, also called glomerulous nephropathy — this causes thickening of the lining of the filters
- nephritis, which is inflammation of the kidneys
Nephrotic syndrome symptoms
One of the most common symptoms of nephrotic syndrome is fluid retention, which causes puffy eyes, a swollen abdomen and swollen ankles and feet.
Other symptoms can include:
- frothy urine
- extreme tiredness
- anaemia (lack of red blood cells)
Nephrotic syndrome can lead to serious illness such as blood clots and kidney failure.
Nephrotic syndrome diagnosis
To confirm whether you have nephrotic syndrome, your doctor is likely to:
- assess your symptoms
- take your medical history
- examine you
- ask you to do a series of urine tests, usually over a 24-hour period
- take a blood sample for testing
Some people might need a biopsy of their kidney so the sample can be examined and tested.
Nephrotic syndrome treatment
If the cause of kidney damage is known, then it will be treated if possible. It will be important to follow the right diet. You might see a dietitian who is likely to recommend a diet with:
- a reasonable amount of protein, but not too much
- not much fat
- very little salt
You might also be advised to restrict how much fluid you drink.
You might also need medicines to manage the symptoms, such as:
- fluid tablets (diuretics) — to reduce fluid retention
- blood pressure medicine — to reduce pressure in your kidneys’ filters, so that less protein is filtered out
- pneumococcal vaccine — if you are at high risk of infection
- anti-clotting medicine — to help thin your blood if there is a risk of blood clots forming
- steroid tablets — which seems to be helpful for minimal change disease
If you suspect you have nephrotic syndrome symptoms, contact your doctor. You can also use healthdirect's Symptom Checker to learn when to seek professional advice.
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Last reviewed: August 2018