Focal Segmental Glomerulosclerosis (FSGS)

Focal Segmental Glomerulosclerosis (FSGS) is a disease that affects the kidney’s filtering system (glomeruli) causing scarring and loss of large amounts of protein in the urine. FSGS is a common cause of nephrotic syndrome.

What causes FSGS?

There is no single cause of FSGS. When the cause is not known it is called idiopathic or primary FSGS. In some patients FSGS may be the result of a genetic or inherited disease, an infection such as parvovirus or HIV/AIDS, or other kidney diseases that lead to scarring.

What are the symptoms?

Many people with FSGS have no symptoms at all. The most common complaint is edema, or swelling, especially in the legs. Often patients find that their shoes no longer fit, or that they have suddenly put on weight. High blood pressure, or hypertension, is also a very common finding. The hypertension in people with FSGS can often be very difficult to treat.

FSGS can also cause abnormal results in two different routine laboratory tests ordered by your doctor. The first is a test of kidney function called “creatinine." It is measured by taking a blood sample. Everyone has a certain amount of a substance called creatinine floating in his or her blood. This substance is always being produced by healthy muscles, but since the kidneys constantly filter it out the level of creatinine stays low. When the filters become damaged, the level of creatinine left in the blood goes up. A higher level of creatinine alerts the doctor that the kidneys aren’t filtering as well as they should.

The second test is for protein in your urine. Urine normally contains only a very small amount of protein. It is just too big to pass through the filters. But when the filters become scarred or damaged, they can “leak” protein into the urine. If a doctor finds too much protein in your urine, it usually means something is wrong with the filters. Some people with a large amount of protein in their urine say that their urine looks “foamy”, like bubbles built up in dishwater.

None of the above symptoms, or even all of them together, is specific for FSGS. If you or your doctor are concerned about FSGS, the only way to know for sure is to have a kidney biopsy.

How is FSGS diagnosed?

With information obtained from blood tests, urine tests and a kidney biopsy, a physician can determine if a person has FSGS.