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What Is FSGS?

FSGS stands for focal segmental glomerulosclerosis. It is a type of kidney disease that causes scarring in the tiny filters of the kidney, which can lead to protein in the urine and loss of kidney function over time.

What that long name actually means

Focal means only some of the kidney filters are affected.

Segmental means only part of an individual filter is scarred.

Glomerulo refers to the glomeruli, the tiny filters inside your kidneys.

Sclerosis means scarring.

Put together, FSGS means scarring in parts of some kidney filters. That scarring makes it easier for protein to leak out into the urine and harder for the kidneys to do their filtering job.

Common signs and symptoms

  • Foamy urine from protein leaking into the urine
  • Swelling in the legs, ankles, feet, face, or around the eyes
  • Weight gain from fluid retention
  • High blood pressure
  • Changes in kidney function on blood tests

Some people feel well at first and only find out because a urine test shows protein. Others develop major swelling or see their kidney numbers worsen over time.

Not all FSGS is the same

Primary FSGS

This means the disease starts in the kidney filters themselves, without another clear cause found.

Secondary FSGS

This happens when another condition or stress on the kidneys leads to scarring. Examples can include obesity, reduced kidney mass, reflux, past kidney injury, or some infections and medications.

Genetic FSGS

Some people have inherited changes that affect the kidney filters. Genetic testing may be considered in selected cases.

How doctors diagnose FSGS

Urine testing to measure protein, including urine albumin or total protein levels

Blood tests to check creatinine, eGFR, albumin, and cholesterol

Blood pressure review and symptom history

Kidney biopsy in many cases, because biopsy helps confirm the diagnosis

Additional workup to look for possible secondary or genetic causes

A biopsy matters because many kidney diseases can cause protein in the urine. Treatment decisions are stronger when the diagnosis is specific.

Treatment usually has two jobs

Lower the protein leak

ACE inhibitors or ARBs are commonly used because they can lower protein in the urine and help protect kidney function.

Control swelling

Diuretics, sodium reduction, and fluid guidance may help if swelling is a major problem.

Treat the underlying pattern

Some patients with primary FSGS may need steroids or other immune-suppressing medicines. Secondary FSGS is often treated by addressing the underlying stress on the kidneys.

Protect the kidneys long term

Blood pressure control, medication review, and regular lab follow-up are key. Some patients may also be candidates for other kidney-protective medicines depending on their situation.

Questions to ask your nephrologist

  • Do you think my FSGS is primary, secondary, or genetic?
  • How much protein am I spilling in my urine right now?
  • Do I need a kidney biopsy or genetic testing?
  • What is the goal for my blood pressure and urine protein?
  • Which medicines are protecting my kidneys, and what side effects should I watch for?
  • How often should I repeat labs and urine tests?

Track protein, blood pressure, and kidney trends in one place

With diseases like FSGS, small changes over time matter. Keeping your labs, symptoms, and blood pressure organized makes appointments more useful.

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