What is Nephrotic Syndrome?
Nephrotic Syndrome (NS) is not a disease itself, but rather a set of signs and symptoms that result from damage in the kidney’s filtering units, called glomeruli.
The glomeruli filter blood as it passes through the kidneys, separating things the body needs from those it doesn’t. Healthy glomeruli keep blood protein (mainly albumin) from seeping into the urine. Damaged glomeruli allow too much blood protein to leave the body, leading to Nephrotic Syndrome.
How is Nephrotic Syndrome Diagnosed?
Urinalysis: determines the amount of protein in the urine
Blood Work: determines the levels of Creatinine, albumin, cholesterol, and many other factors examined in order to rule out other causes
Glomerular Filtration Rate (GFR): an estimator of kidney function through calculating blood creatinine levels with urine protein levels
Kidney Biopsy: sometimes performed to examine a small portion of the kidney under a microscope
Renal Ultrasound or CT Scan: sometimes performed to get a closer look at the kidneys
What are the Symptoms of Nephrotic Syndrome?
Patients with NS often experience:
- High levels of protein in urine (“spilling protein”)
- Low blood protein due to leakage/spilling in the urine
- Foamy urine
- Swelling, typically around the eyes, feet, and hands and sometimes pitting edema
- Weight gain from excess water
- Sometimes high blood pressure
- Sometimes high blood cholesterol levels
What Causes Nephrotic Syndrome?
Nephrotic Syndrome can be “primary” or “secondary” in nature.
Primary Nephrotic Syndrome
Most often, Nephrotic Syndrome is defined by its primary diseases that attack the kidney’s filtering system. Doctors often call these diseases “idiopathic,” which means that they have arisen from an unknown cause.
- Minimal Change Disease (MCD) – most common in children
- Focal Segmental Glomerulosclerosis (FSGS)
- Membranous Nephropathy (MN) – most common in adults
- Other Glomerular Diseases
Secondary Nephrotic Syndrome
Secondary NS is associated with an underlying cause or condition. You may have secondary nephrotic syndrome if you have also been diagnosed with one of the following:
- Vasculitis: Lupus
- Infection: Hepatitis, HIV, CMV, others
- Metabolic disorder: Diabetes
- Cancer: Lymphoma
- Renal Vein Thrombosis
- Heart Failure: Constrictive Pericarditis
- Medications, toxins, IV drug abuse
Who Gets Nephrotic Syndrome?
Although primary NS is a relatively rare condition, anyone can get it. NS is one of the most common contributors of Chronic Kidney Disease (CKD) and responsible for 12% of kidney failure in adults and 20% in children.
- Nephrotic syndrome may affect adults and children of both sexes and of any race.
- 2-4 out of every 100,000 children are diagnosed with primary NS each year in North America and the rates are higher in some other countries.
- Adult incidence of primary NS each year is 3 out of every 100,000 individuals.
- Males are more likely to be diagnosed with NS than females.
- FSGS is the most common primary NS disease in African American patients (50-57% of African American NS diagnoses).
- MN is the most common primary NS disease in adult Caucasian patients.
How is Nephrotic Syndrome Treated?
It is important to see a kidney specialist on a regular basis to monitor kidney function, degree of proteinuria, cholesterol, and blood pressure. The most common drug used to treat Nephrotic Syndrome is Prednisone. Many different types of immunosuppressants, or drugs that suppress the immune system, can also be considered.
Your nephrologist may also recommend:
- Diuretics and/or low salt diet help to control edema
- A medication that blocks a hormone system called the renin angiotensin system (ACE inhibitor or ARB) to control blood pressure or lower the amount of protein being spilled in the urine
- Anticoagulants to prevent blood clots
- Statins to lower the cholesterol level
- Maintaining a healthy diet: which might included different amounts of protein and fluid intake according to your nephrologist’s recommendations. A healthy diet consists of low salt with emphasis on fruits and vegetables that is also low in saturated fat and cholesterol. A low salt diet may also help with swelling.
- Not smoking
1. National Kidney Foundation of Michigan, Merck: http://www.merck.com/mmpe/sec17/ch233/ch233c.html
2. Fine JL, Grzybicki DM, Silowash R, Ho J, et al. Evaluation of whole slide image immunohistochemistryinterpretation in challenging prostate needle biopsies. Hum Pathol 2008; 39: 564-572.