Small blood vessels in your kidneys function as a filter, clearing out waste and extra water from your blood. That waste and water ends up in your bladder and leaves your body as urine. These vessels are part of what’s called “glomeruli,” the filtering part of your kidney.
When they’re damaged, too much protein slips through the filters into your urine. The result is nephrotic syndrome.
Nephrotic syndrome can affect both adults and children. It is treatable.
You might have a condition that affects only your kidneys. Doctors call that a “primary” cause of nephrotic syndrome.
Or you might have an issue with another part of your body that also affects your kidneys. That’s called a “secondary” cause of nephrotic syndrome.
Some of the conditions that can damage your glomeruli include:
Minimal change disease, which is the main cause of nephrotic syndrome in children. Kidney tissue from people with this disease looks relatively normal under a microscope. Doctors don’t know why this disease stops the kidneys from working properly. Some potential causes of the disease include infections from viruses, allergic reactions, taking certain medications, and using non-steroidal anti-inflammatory drugs (NSAIDs)
Focal segmental glomerulosclerosis, or FSGS, is a disease that scars the glomeruli. It’s the most common primary cause of nephrotic syndrome in adults. FSGS can also be caused by a virus (such as HIV), medications, genetic mutations, obesity, high blood pressure and vascular disease, and many others
Membranous nephropathy, in which the membranes of the glomeruli thicken. PLA2R antibodies cause the majority of primary membranous nephropathies. Secondary causes may include cancer, malaria, hepatitis B, and lupus.
There are four main signs or symptoms that make up nephrotic syndrome. They are:
- Too much protein in your urine. Doctors call this proteinuria.
- High fat and cholesterol levels in the blood. The medical term for it is “hyperlipidemia.”
- Swelling of your legs, feet and ankles, and sometimes of your hands and face. This is called edema.
- Low levels of albumin in your blood. Your doctor may call this “hypoalbuminemia.”
Who’s at Risk?
Certain conditions -- such as diabetes, lupus, and amyloidosis -- make you more likely to get nephrotic syndrome.
Some infections can raise the chances you’ll get nephrotic syndrome. They include:
If you think you have symptoms of nephrotic syndrome, make an appointment with your doctor.
You’ll take a urine test, which will measure how much protein your kidneys are filtering out. You may also get blood tests that check on other kidney functions.
Your doctor might also check for diseases that could be a secondary cause of nephrotic syndrome, such as diabetes.
Some people will need a kidney biopsy, which requires taking a tissue sample for study under a microscope.
Without treatment, nephrotic syndrome can cause other problems, including:
- Blood clots. These may form because you’ve lost too much protein from the blood, affecting your body’s ability to prevent clots.
- High cholesterol and triglycerides
- High blood pressure
- Kidney failure, because your damaged kidneys can no longer remove waste products from your bloodstream on their own
- Infections such as pneumonia and meningitis because your body loses infection-fighting proteins called immunoglobulins
Your doctor’s plan will depend on the cause of your nephrotic syndrome. If a different condition is to blame, that will be the first thing to treat. Lowering your cholesterol and blood pressure as well as reducing edema may be key goals.
Medicines you might take include:
- Blood-pressure medications called ACE inhibitors and ARBs, which curb the pressure in your glomeruli and lower the amount of protein in your urine
- Diuretics, or water pills, to reduce swelling
- Cholesterol-lowering drugs
- Blood thinners, or anticoagulants, to make blood clots less likely
- Medications that turn down your immune system, such as corticosteroids
If your nephrotic syndrome doesn’t get better with these treatments, you might need dialysis, a treatment in which a machine filters your blood because your kidneys can’t do the job.
Can I Prevent It?
You can’t prevent some causes of nephrotic syndrome. But you can take action to avoid damage to your glomeruli:
- Manage high blood pressure and diabetes, if you have them
- Be sure to get vaccines for common infections, especially if you work around people who have hepatitis or other diseases
- If your doctor prescribes antibiotics, take them as directed and finish every prescription, even if you start to feel better