Nehrotic tic syndrome is a kidney disorder that causes your body to excrete too much protein in your urine. Nephrotic syndrome is usually caused by damage to the clusters of small blood vessels in your kidneys that filter waste and excess water from your blood. Nephrotic syndrome causes swelling (edema), particularly in your feet and ankles, and increases the risk of other health problems.

Treatment for nephrotic syndrome includes treating the underlying condition that's causing it and taking medications. Nephrotic syndrome can increase your risk of infections and blood clots. Your doctor may recommend steps to prevent these and other complications of nephrotic syndrome.

Symptoms

Signs and symptoms of nephrotic syndrome include:

  • 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

When to see a doctor

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

Nephrotic syndrome is usually caused by damage to the clusters of tiny blood vessels (glomeruli) of your kidneys. The glomeruli filter your blood as it passes through your kidneys, separating things your body needs from those it doesn't. Healthy glomeruli keep blood protein (mainly albumin) which is needed to maintain the right amount of fluid in your body from seeping into your urine. When damaged, glomeruli allow too much blood protein to leave your body, leading to nephritic syndrome.

Many possible causes

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. The inability of the glomeruli to filter blood properly can lead to loss of blood proteins that help prevent clotting. This increases your risk of developing a blood clot (thrombus) in your veins.
  • High blood cholesterol and elevated blood triglycerides. When the level of the protein albumin in your blood falls, your liver makes more albumin. At the same time, your liver releases more cholesterol and 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.
  • High blood pressure. Damage to your glomeruli and the resulting buildup of wastes in your bloodstream (uremia) can raise your 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 - an artificial means of removing extra fluids and waste from your blood - typically with an artificial kidney machine (dialyzer).
  • Chronic kidney failure. Nephrotic syndrome may cause your kidneys to gradually lose their function over time. If kidney function falls low enough, you may require dialysis or a kidney transplant.
  • Infections. People with nephrotic syndrome have an increased risk of infections.

Tests and procedures used to diagnose nephrotic syndrome include:

  • Urine tests. A urinalysis can reveal abnormalities in your urine, such as large amounts of protein, if you have nephrotic syndrome. You may be asked to collect urine samples over 24 hours for an accurate measure of the protein in your urine.
  • Blood tests. If you have nephrotic syndrome, a blood test may show low levels of the protein albumin (hypoalbuminemia) specifically and, often, decreased levels of blood protein overall. Loss of albumin is often associated with an increase in blood cholesterol and blood triglycerides. Serum creatinine and blood urea also may be measured to assess your overall kidney function.
  • Removing a sample of kidney tissue for testing. Your doctor may recommend a procedure called a kidney biopsy to remove a small sample of kidney tissue for testing. During a kidney biopsy, a special needle is inserted through your skin and into your kidney. Kidney tissue is collected and sent to a laboratory for testing.