Focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is a cause of nephrotic syndrome in children and adolescents, as well as an important cause of kidney failure in adults. Minimal change disease (MCD) is by far the most common cause of nephrotic syndrome in children. MCD and primary FSGS may have a similar cause.

The individual components of the name refer to the appearance of the kidney tissue on biopsy: focal - only some of the glomeruli are involved (as opposed to diffuse), segmental - only part of an entire glomerulus is involved (as opposed to global), glomerulosclerosis - refers to scarring of the glomerulus (a part of the nephron (the functional unit of the kidney))

Symptoms & Signs

In children and some adults, FSGS presents as a nephrotic syndrome (which is characterized by edema (associated with weight gain), hypoalbuminemia (low albumin (a protein) in the blood), hyperlipidemia and hypertension (high blood pressure)). In adults it may also present as kidney failure and proteinuria, without a full-blown nephrotic syndrome.

Classification

Depending on the cause it is broadly classified as

Primary, when no underlying cause is found; usually presents as nephrotic syndrome
Secondary, when an underlying cause is identified; usually presents with kidney failure and proteinuria. This is actually a heterogenous group including a myriad causes such as
- Infections such as HIV
- Toxins and drugs such as heroin and pamidronate
- Familial forms
- Secondary to nephron loss and hyperfiltration, such as with chronic pyelonephritis and reflux, morbid obesity, diabetes mellitus

There are many other classification schemes also.

Diagnosis

urinalysis
blood tests - cholesterol
kidney biopsy

Differential Diagnosis

Minimal change disease, especially in children
several others

Treatment

salt restriction and diuretics (water pills), such as furosemide, for edema
antihypertensives (especially ACEIs) - if the blood pressure is too high
treat present hyperlipidemia (e.g. statins, fibrates)
Corticosteroids, such as prednisone - based on the clinical judgment of physician (no broad consensus/guideline)
Plasmapheresis - blood cleansing using a machine to remove the patient's plasma and replaccing it with donor plasma.
None - sometimes none of the above works and the patient will required dialysis with possibly later transplantation of a new kidney

External links

Kidcomm An online resource for parents dealing with childhood kidney diseases (FSGS)

Nephrology