What is Nephrotic Syndrome?

Nephrotic syndrome is a kidney disorder that causes your body to excrete too much protein (which is normally kept in the plasma of the blood) in your urine. It is usually caused by damage to the clusters of small blood vessels in your kidneys that filter waste and excess water from your blood. You may also have high levels of cholesterol in your blood with nephrotic syndrome.

Nephrotic syndrome isn't a disease. It's a warning that something is damaging your kidneys. Without treatment, that problem could cause kidney failure. So it's important to get treatment right away.

What are the signs and symptoms of nephrotic syndrome?

  • Severe swelling (edema), particularly around your eyes and in your ankles and feet
  • Foamy urine, which may be caused by excess protein in your urine
  • Weight gain due to excess fluid retention

Make an appointment with your doctor if you see any signs or symptoms that worry you.

What causes nephrotic syndrome?

The kidneys have tiny blood vessels called glomeruli that filter waste and extra water from the blood. Healthy kidneys keep the right amount of protein in the blood. Protein helps move water from the tissues into the blood. When the tiny filters are damaged, too much protein slips from the blood into the urine. As a result, fluid builds up in the tissues and causes swelling.

Many diseases and conditions can cause glomerular damage and lead to nephrotic syndrome, including:

  • Minimal change disease. The most common cause of nephrotic syndrome in children, this disorder results in abnormal kidney function, but when the kidney tissue is examined under a microscope, it appears normal or nearly normal. The cause of the abnormal function typically can't be determined.
  • Focal segmental glomerulosclerosis. Characterized by scattered scarring of some of the glomeruli, this condition may result from another disease or a genetic defect or occur for no known reason.
  • Membranous nephropathy. This kidney disorder is the result of thickening membranes within the glomeruli. The exact cause of the thickening isn't known, but it's sometimes associated with other medical conditions, such as hepatitis B, malaria, lupus and cancer.
  • Diabetic kidney disease. Diabetes can lead to kidney damage (diabetic nephropathy) that affects the glomeruli.
  • Systemic lupus erythematosus. This chronic inflammatory disease can lead to serious kidney damage.
  • Amyloidosis. This disorder occurs when substances called amyloid proteins accumulate in your organs. Amyloid buildup often affects the kidneys, damaging their filtering system.
  • Blood clot in a kidney vein. Renal vein thrombosis, which occurs when a blood clot blocks a vein connected to the kidney, can cause nephrotic syndrome.
  • Heart failure. Some forms of heart failure, such as constrictive pericarditis and severe right heart failure, can cause nephrotic syndrome.

Possible complications of nephrotic syndrome include:

  • Blood clots (thrombus) formation in your veins.
  • High blood cholesterol and elevated blood triglycerides.
  • Poor nutrition. Loss of too much blood protein can result in malnutrition. This can lead to weight loss, but it may be masked by swelling. You may also have too few red blood cells (anemia) and low levels of vitamin D and calcium.
  • High blood pressure.
  • Acute kidney failure. If your kidneys lose their ability to filter blood due to damage to the glomeruli, waste products may build up quickly in your blood. If this happens, you may need emergency dialysis.
  • Chronic kidney disease. Nephrotic syndrome may cause your kidneys to gradually lose their function over time.
  • Infections. People with nephrotic syndrome have an increased risk of infections.

Diagnosis of nephrotic syndrome:

  • Urine Analysis (to confirm high level of proteins in urine).
  • Blood Test to detect the Albumin protein level which is lowered in Nephrotic Syndrome).
  • Kidney Biopsy which is removing a sample of your kidney for testing to be able to detect the cause of nephrotic syndrome (During a kidney biopsy, a special needle is inserted through your skin and into your kidney. Kidney tissue is collected and sent to a lab for testing.)


Treatment for nephrotic syndrome involves treating the underlying medical condition. Your doctor may also recommend medications that may help control your signs and symptoms or treat complications of nephrotic syndrome. These may include Blood Pressure medications, Water Pills (to help decrease the generalized body swelling), Cholesterol reducing medications, Blood thinners and Immune system suppressing medications. 

Changes to your diet may help you cope with nephrotic syndrome:

  • Choose lean sources of protein
  • Reduce the amount of fat and cholesterol in your diet.
  • Eat a low-salt diet to help control the swellingyou experience so this would easen up your symptoms. 

Disclaimer: The UCLA Health System cannot guarantee the accuracy of such information. The information is provided without warranty or guarantee of any kind. Please speak to your Physician before making any changes.