Focal Segmental Glomerulosclerosis (FSGS)
What is Focal Segmental Glomerulosclerosis (FSGS)?
Focal segmental glomerulosclerosis is a kidney disease that causes scarring in the glomeruli. Glomeruli are tiny filters in your kidneys that clean waste from your blood. When these filters become scarred, they can no longer do their job properly. Protein leaks from your blood into your urine instead of staying where it belongs.
FSGS is one of the most common causes of nephrotic syndrome in adults. Nephrotic syndrome means your kidneys leak large amounts of protein into your urine. This protein loss can lead to swelling, high cholesterol, and other health problems. The disease can progress slowly or quickly depending on the type and severity.
FSGS affects only some glomeruli at first, which is what focal means. Within the affected glomeruli, only certain sections show scarring, which is the segmental part. Without treatment, FSGS can lead to kidney failure over time. Early detection through blood and urine testing helps protect your kidney function before permanent damage occurs.
Symptoms
- Foamy or bubbly urine from high protein levels
- Swelling in the legs, ankles, feet, or around the eyes
- Weight gain from fluid retention
- Fatigue and low energy levels
- Loss of appetite
- High blood pressure
- High cholesterol levels
- Decreased urine output
Some people with early FSGS have no symptoms at all. The condition may only be discovered during routine blood or urine testing. This is why regular kidney function monitoring is important, especially if you have risk factors for kidney disease.
Concerned about Focal Segmental Glomerulosclerosis (FSGS)? Check your levels.
Screen for 1,200+ health conditions
Causes and risk factors
FSGS can be primary, meaning it occurs without a known cause, or secondary, meaning it results from another condition. Primary FSGS may involve genetic mutations that affect the structure of kidney filters. Secondary FSGS can be triggered by viral infections like HIV, obesity, sickle cell disease, or certain medications. Reflux nephropathy and reduced kidney mass from birth defects or surgery can also cause the condition.
Risk factors include African American or Hispanic ethnicity, which increases susceptibility to certain genetic forms. A family history of kidney disease raises your risk significantly. Obesity puts extra strain on kidney filters and may trigger scarring. High blood pressure damages small blood vessels in the kidneys over time. Some people develop FSGS after years of using heroin or other illicit drugs. Knowing your risk factors helps you and your doctor watch for early signs of kidney damage.
How it's diagnosed
FSGS is diagnosed through a combination of blood tests, urine tests, and kidney biopsy. Blood tests measure cystatin C, which tracks kidney filtration function more accurately than standard tests. As FSGS progresses, cystatin C levels rise, showing declining kidney function. Urine protein testing reveals how much protein is leaking through damaged kidney filters. High protein levels in urine are the hallmark sign of FSGS and correlate with disease severity.
A kidney biopsy provides the definitive diagnosis by showing the characteristic scarring pattern under a microscope. Your doctor will examine a small tissue sample to see which glomeruli are affected and how extensive the damage is. Rite Aid offers cystatin C and urine protein testing to monitor kidney function and detect protein loss early. Regular testing helps track disease progression and treatment response over time.
Treatment options
- Blood pressure medications, especially ACE inhibitors or ARBs, to reduce protein leakage and protect kidney function
- Corticosteroids like prednisone to reduce inflammation and scarring in some cases
- Immunosuppressive medications such as cyclosporine or tacrolimus when steroids are not enough
- Diuretics to reduce swelling and fluid retention
- Cholesterol-lowering medications called statins
- Low-sodium diet to help control blood pressure and reduce swelling
- Moderate protein intake, adjusted based on your kidney function and protein loss
- Weight loss if you are overweight, which reduces strain on kidney filters
- Regular exercise to support overall health and blood pressure control
- Avoiding NSAIDs like ibuprofen, which can further damage kidneys
- Dialysis or kidney transplant if the disease progresses to kidney failure
Concerned about Focal Segmental Glomerulosclerosis (FSGS)? Get tested at Rite Aid.
- Simple blood draw at your nearest lab
- Results in days, not weeks
- Share results with your doctor
Frequently asked questions
FSGS specifically causes scarring in segments of some glomeruli, the kidney's tiny filters. Other kidney diseases may damage different parts of the kidney or affect all glomeruli uniformly. FSGS is particularly known for causing severe protein loss in urine, which is called nephrotic syndrome. The scarring pattern seen on kidney biopsy distinguishes FSGS from conditions like minimal change disease or membranous nephropathy.
FSGS progression varies widely from person to person. Some people progress to kidney failure within a few years, while others maintain stable kidney function for decades. Higher levels of protein in urine generally indicate faster progression. Response to treatment is the best predictor of outcome, with those achieving reduced protein levels having better long-term kidney function.
FSGS cannot be cured, but it can often be managed effectively with treatment. Some people achieve complete remission, meaning their protein levels return to normal and kidney function stabilizes. Others achieve partial remission with reduced but not normal protein levels. Treatment focuses on slowing disease progression and preventing kidney failure.
Foamy urine occurs because damaged kidney filters leak large amounts of protein into your urine. When protein concentration is high, it creates bubbles and foam, similar to soap in water. This is often the first visible sign people notice with FSGS. The amount of foam generally correlates with the severity of protein loss.
Most people with FSGS need blood and urine testing every 3 to 6 months to monitor kidney function and protein levels. More frequent testing may be needed when starting new medications or if your condition is changing. Regular monitoring with cystatin C helps detect changes in kidney filtration before serious damage occurs. Your doctor will recommend a testing schedule based on your disease severity and treatment plan.
Some forms of FSGS are hereditary, caused by genetic mutations passed down in families. These genetic forms typically appear in childhood or young adulthood. However, most cases of FSGS are not directly inherited and occur sporadically. If you have a family history of kidney disease, genetic testing and counseling may be recommended.
A low-sodium diet helps control blood pressure and reduce swelling in FSGS. Limiting protein intake may reduce strain on damaged kidneys, but you still need adequate protein for overall health. Reducing saturated fat helps manage the high cholesterol that often accompanies FSGS. Working with a kidney dietitian ensures you get proper nutrition while protecting your kidney function.
Yes, weight loss can significantly benefit people with obesity-related FSGS. Losing excess weight reduces strain on kidney filters and may lead to reduced protein loss. Some studies show that substantial weight loss can even lead to remission in obesity-related cases. Even modest weight loss of 5 to 10 percent of body weight can improve kidney function markers.
Not everyone with FSGS needs dialysis, but the disease does carry a risk of progressing to kidney failure. About 50 percent of people with FSGS develop end-stage kidney disease within 10 years without treatment. Early diagnosis and effective treatment significantly reduce this risk. Regular monitoring helps catch declining kidney function early so interventions can delay or prevent the need for dialysis.
FSGS can recur in the transplanted kidney, especially in cases of primary FSGS. Recurrence rates range from 30 to 50 percent and often happen within days to months after transplant. Higher protein levels before transplant increase the risk of recurrence. Despite this risk, kidney transplant remains the best treatment option for people who progress to kidney failure from FSGS.