Focal segmental glomerulosclerosis, or FSGS, is a disease affecting the kidneys. It is a form of glomerulonephritis, a disease in which the glomeruli are damaged. Glomeruli consist of many tiny units inside each kidney which filter blood as part of the process of urine formation. In focal segmental glomerulosclerosis, scarring occurs inside some of the glomeruli. The disease is described as focal because it affects only some of the glomeruli and segmental because only a segment, or part, of each one is damaged.
When the type of scarring seen in focal segmental glomerulosclerosis is the result of another disease affecting the kidney it is known as secondary FSGS. In what is called primary focal segmental glomerulosclerosis the cause is unknown. Typically, when people refer to focal segmental glomerulosclerosis it is the primary form of the disease which is being discussed.
Symptoms of focal segmental glomerulosclerosis can vary, but may include loss of appetite, swollen ankles, fluid retention and increased weight. The presence of protein in the urine could cause it to appear foamy. Sometimes no symptoms are experienced but protein is detected in the urine during a routine check. When large amounts of protein are lost in the urine and excess fluid causes the ankles to swell, this is known as nephrotic syndrome, a condition which can be caused by a number of kidney diseases.
Complications of focal segmental glomerulosclerosis can include high blood pressure, or hypertension, which may in turn cause further damage to the kidneys. Cholesterol levels can rise in some people. The function of the kidneys may deteriorate and, in more severe cases, kidney failure could occur.
For some people, treatment with steroids can be successful, and high doses can lead to an improvement. Other drugs which act on the immune system, such as cyclosporin, may be beneficial if steroids fail to work. It is important to treat the symptoms of FSGS, and therapies may include special diets, salt restriction, and drugs which reduce blood pressure, cholesterol and excess fluid. If the kidneys fail, dialysis and a kidney transplant may be required.
The outlook for people with focal segmental glomerulosclerosis is variable. Sometimes the disease remains stable for a number of years, and occasionally it can go away by itself. If excess fluid and swollen ankles occur, these factors may worsen. Within a period of ten years, it is thought that more than half of FSGS cases will progress to kidney failure.