What is nephrotic syndrome?
Nephrotic (neff-rot-ick) syndrome is a condition in which your kidneys release an excessive amount of protein (proteinuria) in your urine (pee).
Nephrotic syndrome usually results from a problem with your kidneys’ filters (glomeruli). Glomeruli (glo-mare-yoo-lye) are tiny blood vessels in your kidneys. They remove wastes and excess fluids from your blood and send them to your bladder as urine. Common waste products include nitrogen waste (urea), muscle waste (creatinine) and acids.
In healthy kidneys, the glomeruli filter out the waste products. They allow your blood to retain the cells and proteins your body needs to function regularly.
Damaged glomeruli allow blood proteins to leak into your pee, including albumin. If you have nephrotic syndrome, your damaged glomeruli allow three or more grams (g) of protein to leak into your pee over 24 hours. Three grams is a little heavier than a U.S. penny. It’s 20 times the amount of protein that healthy glomeruli allow.
Is nephrotic syndrome life-threatening?
Nephrotic syndrome is a serious condition. Without treatment, nephrotic syndrome can affect your life expectancy due to secondary complications.
Who does nephrotic syndrome affect?
Nephrotic syndrome can affect anyone. However, it’s most common in people with diabetes-related kidney disease, people who have allergies and people who have a biological family history of kidney disease with nephrotic syndrome.
How common is nephrotic syndrome?
Nephrotic syndrome is relatively rare.
Nephrotic syndrome occurs in about 1 in every 50,000 children each year. Most children receive a nephrotic syndrome diagnosis between the ages of 2 and 5. Boys and children assigned male at birth (AMAB) are about twice as likely to have nephrotic syndrome as girls or children assigned female at birth (AFAB).
It occurs in 3 in every 100,000 adults each year.
How does nephrotic syndrome affect my body?
If you have nephrotic syndrome, losing different proteins may cause various problems.
Some proteins help prevent blood clots. When you lose those proteins in your pee, blood clots can form.
Immunoglobulins are proteins that help your immune system fight diseases and infection. When you lose immunoglobulins, you’re at a greater risk of general infections that affect different body systems, including:
Symptoms and Causes
What are the symptoms of nephrotic syndrome?
Common nephrotic syndrome symptoms include:
- Large amounts (greater than 3.5 grams) of the protein albumin in your pee (albuminuria).
- High fat and cholesterol levels in your blood (hyperlipidemia).
- Swelling (edema), usually in your legs, feet or ankles. Swelling may also occur in your hands or face.
- Low levels of albumin in your blood (hypoalbuminemia).
- Loss of appetite.
- Feeling unwell or sick.
- Abdominal pain (pain anywhere from your ribs to your pelvis).
- Foamy pee.
Another symptom of nephrotic syndrome is a loss of minerals and vitamins that are essential to your health and development, including calcium and vitamin D. In children with nephrotic syndrome, this may affect their growth. You may develop osteoporosis, which weakens your hair and nails.
What is the most common complication of nephrotic syndrome?
The most common complications of nephrotic syndrome include:
- Acute kidney injury. Your kidney suddenly stops functioning properly.
- Anemia. You don’t have enough healthy blood cells to carry oxygen to your body’s organs.
- Coronary artery disease. Plaque builds up in the arteries that supply blood to your heart.
- Hypertension (high blood pressure). The blood that flows through your blood vessels travels with a greater force than usual.
- Hypothyroidism. Your thyroid gland doesn’t produce and release enough of the thyroid hormone into your bloodstream.
What causes nephrotic syndrome?
Kidney diseases often damage your glomeruli. The diseases target your glomeruli, though healthcare providers and medical researchers aren’t sure why. Damaged glomeruli are the primary cause of nephrotic syndrome. These diseases include:
- Amyloidosis. This is a disease in which amyloid proteins build up in your vital organs. Amyloidosis most commonly occurs in your kidneys, affecting their ability to filter.
- Diabetes-related nephropathy. “Nephropathy” means that your kidney isn’t working properly. In diabetes-related nephropathy, diabetes causes damage or dysfunction to one or more of the nerves in your kidneys. It typically causes numbness, tingling, muscle weakness and pain in your affected area.
- Focal segmental glomerulosclerosis (FSGS). In FSGS, scarring affects small areas (segments) of some of your glomeruli. It may cause swelling, kidney failure and loss of proteins in your pee.
- Lupus. Lupus is an autoimmune disease that causes inflammation, swelling and pain throughout your body, including your kidneys.
- Membranous nephropathy. In membranous nephropathy, your body’s immune system attacks the filtering membranes in your kidneys.
- Minimal change disease (MCD). This is a type of nephropathy in which your kidneys aren’t working properly. However, a kidney biopsy shows little or no damage to your glomeruli or kidney tissue. MCD may occur at any age, but it’s most common in children.
Diagnosis and Tests
How do you diagnose nephrotic syndrome?
The following tests and procedures help diagnose nephrotic syndrome:
A urinalysis (urine test) examines the visual, chemical and microscopic aspects of your pee. Your healthcare provider may recommend a few different types of urinalysis tests.
During a dipstick test, you’ll pee into a special container at your healthcare provider’s office or a hospital. Then, a healthcare provider will place a strip of paper coated with special chemicals (dipstick) into the container. The dipstick will change color if there’s albumin in your pee.
If your healthcare provider needs a more precise measurement, they may recommend urine protein tests. Urine protein tests may include a single urine sample or a 24-hour collection of urine.
In a single urine sample, your container is sent to a lab. Lab technicians compare how much albumin and creatinine are in your pee (albumin-to-creatinine ratio). If your urine sample has more than 30 milligrams (mg) of albumin for each gram of creatinine, it may signal a problem.
In a 24-hour urine collection, your healthcare provider will give you a container to collect your pee from home. On the day of the test, you’ll:
- Pee in the toilet as usual when you first wake up.
- Pee in the container the rest of the day until you go to sleep.
- Pee in the container one last time when you first wake up the following day.
You’ll then drop your sample off at your healthcare provider’s office or a lab. Lab technicians will only measure the amount of albumin in your sample.
During an albumin blood test, your healthcare provider will use a thin needle to withdraw a small amount of blood from a vein in your arm. The blood sample goes to a lab for testing. A low level of albumin or other proteins may indicate nephrotic syndrome.
Lab technicians may also test your blood cholesterol and blood triglyceride levels. Those levels may increase if your blood albumin level is low.
During a kidney biopsy, your healthcare provider will remove a small piece of your kidney tissue to examine at a lab under a microscope.
Your healthcare provider will first numb the area with a local anesthetic so you won’t feel any pain. They’ll also give you a light sedative to help you relax. Then, they’ll insert a needle through your skin and into your kidney to collect the tissue sample.
If you have diabetes and your healthcare provider suspects you have nephrotic syndrome, you likely won’t need a kidney biopsy. Your medical history, urine tests and blood tests are often enough to help them diagnose nephrotic syndrome as a result of your diabetes.
Management and Treatment
Is nephrotic syndrome curable?
No, nephrotic syndrome isn’t curable. However, nephrotic syndrome often goes away in children once they reach their late teenage years or early 20s.
Treatment helps relieve your nephrotic syndrome symptoms and prevents further damage to your kidneys.
Nephrotic syndrome treatment includes addressing the underlying cause and taking steps to reduce high blood pressure, high cholesterol, swelling and infection risks. Treatment usually includes medications and changes to your diet.
Some blood pressure medications can slow down a kidney disease that causes nephrotic syndrome, including:
- Angiotensin-converting enzyme (ACE) inhibitors.
- Angiotensin receptor blockers (ARBs).
These medications reduce the pressure inside your glomeruli, which reduces albuminuria. Many people require two or more medications to regulate their blood pressure.
In addition to an ACE inhibitor or an ARB, your healthcare provider may recommend a diuretic. Diuretics help your kidneys remove fluid from your blood. Diuretics also help reduce blood pressure and swelling. Other medications that help lower your blood pressure include beta-blockers and calcium channel blockers.
To lower your cholesterol, your healthcare provider may recommend statin medications.
If you have nephrotic syndrome, it’s also a good idea to get a yearly influenza (flu) vaccine and a pneumococcal (new-ma-cah-cole) vaccine. A pneumococcal vaccine helps protect your body from a pneumococcus (new-ma-cah-cuss) bacterial infection. These bacteria may cause ear infections, strep throat, pneumonia and meningitis.
In some cases, your healthcare provider may recommend medications that help prevent blood clots (anticoagulants or blood thinners). If you have nephrotic syndrome, you’ll only take these medications if you develop a blood clot. They don’t prevent nephrotic syndrome or any symptoms of nephrotic syndrome.
Should I avoid any foods or drinks if I have nephrotic syndrome?
Diet and nutrition don’t cause or prevent nephrotic syndrome in adults. However, if you have nephrotic syndrome, changes to your diet may help relieve some of your symptoms.
You can help reduce swelling by limiting the amount of sodium in your diet. Most sodium in your diet comes from salt. You can also help reduce swelling by drinking more fluids.
Reducing saturated fat and cholesterol in your diet can help manage hyperlipidemia. It’s a good idea to limit foods like full-fat dairy, red meat, processed meat, cheese, fried foods, baked goods and sweets.
How do I take care of myself?
The best way to manage your symptoms is to take your medications as prescribed by your healthcare provider. It’s also a good idea to maintain a diet with appropriate amounts of potassium and protein but low amounts of sodium, saturated fat and cholesterol.
How soon after treatment will I feel better?
It depends on the cause of your nephrotic syndrome. Some people may start to feel better a few days after treatment, while it may take others a few weeks or even months.
How can I prevent nephrotic syndrome?
You can’t prevent nephrotic syndrome. However, you can improve the symptoms of nephrotic syndrome by treating its cause and making changes to your diet.
Outlook / Prognosis
What can I expect if I have nephrotic syndrome?
With proper diagnosis and treatment, the outcome for people with nephrotic syndrome is good. Most people respond well to treatment, and nephrotic syndrome often goes into remission.
If you have nephrotic syndrome as a child, it often goes away by your early adult years.
When should I see my healthcare provider?
Contact your healthcare provider as soon as you notice any kidney symptoms that last longer than a few days, especially if your pee is foamy.
What questions should I ask my healthcare provider?
- How do you know that I have nephrotic syndrome?
- Do I need to take any tests to confirm your diagnosis?
- If I don’t have nephrotic syndrome, what other condition might I have?
- What condition caused me to develop nephrotic syndrome?
- Do you think my nephrotic syndrome will go into remission with treatment?
- Do you think my child’s nephrotic syndrome will go away when they get older?
- What medications or treatments do you recommend?
- Should I make any changes to my diet?
Frequently Asked Questions
What’s the difference between nephrotic syndrome and nephritic syndrome?
Nephrotic syndrome and nephritic syndrome are both conditions that affect your kidneys.
The primary feature of nephrotic syndrome is a large amount of protein in your blood.
The primary feature of nephritic system is inflammation, usually from an infection, vascular disease or degeneration.
What’s the difference between nephrotic syndrome and glomerulonephritis?
Glomerulonephritis is also a type of kidney disease, and its symptoms are similar to nephrotic syndrome. However, your kidneys release more protein through your urine if you have nephrotic syndrome. You’ll lose more than 3.5 grams of protein if you have nephrotic syndrome. You’ll lose less than 3.5 grams of protein if you have glomerulonephritis.
What is congenital nephrotic syndrome?
Congenital nephrotic syndrome exists at birth. It usually causes permanent kidney failure between the ages of 2 and 8. It’s an inherited kidney disease, which means your parents passed it down to you.
A note from Cleveland Clinic
Nephrotic syndrome is a kidney disease that causes you to lose proteins in your pee. If you have nephrotic syndrome, you may have pain in your abdomen, foamy pee and a general feeling of illness. If you’ve had any of these symptoms for more than a few days, it’s a good idea to reach out to your healthcare provider. They can prescribe treatments that can help keep your kidneys healthy.
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