What is FSGS?

M any cases of kidney disease in the United States are linked to other serious medical conditions like high blood pressure or diabetes. But there are also forms of kidney disease that strike without clear cause, and have serious repercussions. Below, two doctors discuss one such disease, called focal segmental glomerulosclerosis, or FSGS.

What is FSGS?
LEONARD STERN, MD: This illness attacks the glomerulus, or the main filtering part of the kidney. There are two forms of FSGS, and they both cause protein to leak into the urine. Over time, the protein acts as a toxin that injures the remaining parts of the nephrons. The rate of the resulting damage fluctuates from patient to patient. For some it is progressive and slow, in others it is rapid. In any case, the damage leads to kidney failure, which requires dialysis or transplant.

How common is the disease?
JAI RADHAKRISHNAN, MD: If you look at all the diseases that cause kidney failure together, FSGS is not common. But it is one of the most common causes of nephrotic syndrome, or leakage of protein from the kidneys to the urine.

Who is most at risk for developing this disease?
LEONARD STERN, MD: It largely affects males, and affects African Americans more than white Americans. It has some association with illicit drug use and HIV and AIDS, and also it is associated with obesity, urinary tract infections and mechanical reflux of urine from the bladder into the uterus.

Is there a suspected relationship between FSGS and autoimmune disorders?
JAI RADHAKRISHNAN, MD: The word "autoimmune" means that the body produces immunity against itself, and in doing so it damages organs. There's data published in both France and the United States that suggests that in FSGS, a protein or substance in the blood goes and destroys the filters of the kidney, causing it to become more leaky, and it's not yet known what this protein is.

How is FSGS discovered?
JAI RADHAKRISHNAN, MD: FSGS is often first identified by detecting protein in the urine. Equally common is the patient who presents with body swelling because of salt and water retention. Patients are also diagnosed with high blood pressure, and not uncommonly, FSGS can progress without any symptoms, causing kidney failure.

LEONARD STERN, MD: Definitive diagnosis comes from a kidney biopsy where ultrasound is used to find the kidney and do a needle biopsy.

How is FSGS treated?
LEONARD STERN, MD: It's very difficult to treat a patient with kidney disease without actually knowing the type of disease, because we treat them with different medications.

Since we don't understand the primary cause in the vast majority of patients, all we do is treat the features of the illness, and those might be related to the high blood pressure that the illness causes, and we directly attack the protein leaking into the urine.

What sorts of medications are used?
JAI RADHAKRISHNAN, MD: If it's the inflammatory type of disease, we try to suppress the immune system with cortical steroids, a form of hormone that's made by the body, given at high doses.

If that fails or if the patient cannot tolerate this, we have cyclosporine or CellCept. Some people have used a process called plasma exchange where the protein that's abnormal in the blood is removed by a process of purification and then normal plasma is given back.

How effective are these treatments?
JAI RADHAKRISHNAN, MD: About one-half of the patients respond to one or the other kind of treatment. It's also very important to control blood pressure in all patients, because high blood pressure could worsen the prognosis of this disease.

Can this disease be cured?
LEONARD STERN, MD: I don't think the illness could be cured by our present medications, but we can place the patient in what we call a "clinical remission." A responder would be someone whose blood pressure is well controlled and the protein in the urine is eliminated.

When that happens, we hope that the patient can sustain that remission for a long period of time. One of the unknown variables is, how long do we treat the patient? It's the subject of much research, but there are not a lot of answers yet.

In what way should the average patient screen for this condition?
LEONARD STERN, MD: During a normal physical examination, the blood pressure needs to be checked, and at some point an examination of the urine should be done. An ordinary urinalysis will detect protein and inflammatory cells, and that's a superb screening test.

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