Focal Segmental Glomerulosclerosis
One type of kidney disease is focal segmental glomerulosclerosis (FSGS). To get a better picture of what the disease is, let’s break down the term from beginning to end.
- Focal means localized and indicates that only some glomeruli — the kidneys’ tiny capillary tufts where fluids, minerals and waste products are filtered from the blood — are affected.
- Segmental means that damage has occurred to only a section of an individual glomerulus.
- Glomerulosclerosis means the scarring of the glomeruli.
Causes of focal segmental glomerulosclerosis
What causes FSGS is often unknown, so it is therefore classified as either primary or secondary FSGS. Primary FSGS means the disease appears spontaneously or without an identifiable cause. Secondary FSGS is linked to a multitude of conditions that include kidney diseases, drug abuse (intravenous heroin, painkillers), viral infections such as hepatitis B or AIDS, cancers, hypertension, obesity, genetic mutations and others.
Symptoms of focal segmental glomerulosclerosis
People who have FSGS often show no signs or symptoms of the disease unless progressive damage to the kidneys severely interferes with their normal function. FSGS can cause asymptomatic proteinuria, a condition where protein leaks into the urine, or nephrotic syndrome, which is characterized by:
- Foamy urine caused by large amounts of protein
- Low serum albumin due to loss of protein
- Weight gain caused by fluid retention
- Edema (swollen ankles, feet, hands, face or abdomen)
- High blood pressure (often seen with primary FSGS)
Diagnosing focal segmental glomerulosclerosis
While no age group is exempt, primary FSGS is often diagnosed in people 18 to 45 years of age. Men are affected more frequently than women, and African Americans are usually affected more than other races.
Because proteinuria and nephrotic syndrome are associated with many other kidney diseases, a kidney biopsy — where a needle is inserted into the kidney and a tiny amount of tissue is examined — is the best way to diagnose FSGS. Once a diagnosis is established, it is recommended to do further studies to see whether the FSGS is primary or secondary, as treatment options may vary.
Treating focal segmental glomerulosclerosis
Treatment is aimed at reducing proteinuria, controlling hypertension, preventing malnutrition and preserving kidney function through general and specific interventions.
Dietary management includes a reduction in salt and fat intake, and keeping protein intake at less than 1 gram of animal protein (including meats, chicken, fish and eggs) per body weight measured in kilograms.
Diuretics — medications that increase urine production — help decrease fluid retention and edema. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) are medications known to reduce proteinuria and are effective even in people without hypertension. Medications that lower high cholesterol may also be beneficial.
People with primary FSGS are usually treated with corticosteroids, such as prednisone, and other immunosuppressive therapy. For people with secondary FSGS, interventions also focus on treating the underlying condition.
Complications of focal segmental glomerulosclerosis
If untreated, about 50 to 70 percent of people with FSGS will eventually experience kidney failure. But even if treated, FSGS may still progress to kidney failure within six to eight years after the onset of proteinuria. Once kidney failure is reached, people will need dialysis or a kidney transplant to survive.
Summary
Focal segmental glomerulosclerosis (FSGS) is a type of kidney disease that scars parts of the glomeruli, the filtering units of the kidney. While FSGS often progresses to kidney failure, there are wide variations in the progression of the disease. Following your doctor’s treatment prescriptions will prolong kidney function for as long as possible, or may even reverse the condition. If kidney failure does occur, treatment options are available.
