Nephrotic Syndrome

Nephrotic syndrome (NS), also known as nephrosis, is defined by the presence of nephrotic-range proteinuria, edema, hyperlipidemia, and hypoalbuminemia. Nephrotic-range proteinuria in adults is characterized by protein excretion of 3.5g or more per day.

Nephrotic syndrome is a constellation of clinical findings that is the result of massive renal losses of protein. Thus, nephrotic syndrome is not a disease itself, but the manifestation of many different glomerular diseases.

The glomerular diseases that cause nephrotic syndrome generally can be divided into primary and secondary etiologies. Primary nephrotic syndrome (PNS), also known as idiopathic nephrotic syndrome (INS), is associated with glomerular diseases intrinsic to the kidney and not related to systemic causes.
Primary causes of nephrotic syndrome include, in approximate order of frequency:
• Minimal-change nephropathy
• Focal glomerulosclerosis
• Membranous nephropathy
• Hereditary nephropathies

By definition, secondary nephrotic syndrome refers to an etiology extrinsic to the kidney, being a renal manifestation of a systemic general illness.
Secondary causes include, again in order of approximate frequency:
• Diabetes mellitus
• Lupus erythematosus
• Amyloidosis and paraproteinemias
• Viral infections (eg, hepatitis B, hepatitis C, human immunodeficiency virus [HIV] )
• Preeclampsia (abnormal state of pregnancy characterized by hypertension and fluid retention and albuminuria)

The cumulative prevalence rate is approximately 16 cases per 100,000 individuals. The following statistics relate to deaths and Nephrotic syndrome:

* 39,480 people died from nephritis, nephrotic syndrome and nephrosis each year in the US 2001 (Deaths: Final Data for 2001, NCHS, CDC)
* 13.9 people per 100,000 population died from nephritis, nephrotic syndrome and nephrosis each year in the US 2001 (Deaths: Final Data for 2001, NCHS, CDC)
* Kidney disease was ranked the ninth leading cause of death in the US 2001 (Deaths: Final Data for 2001, NCHS, CDC)


Diabetic nephropathy (DN) is the most common cause of nephrotic syndrome in adults and of end-stage renal disease in the US, accounting for up to 80% of cases of the latter. The prevalence of renal failure is probably about 40% among patients with type 1 diabetes mellitus. The prevalence of renal failure among patients with type 2 diabetes mellitus is usually stated as 20 to 30%, but this figure is probably low.

Diabetic nephropathy is a clinical syndrome characterized by persistent albuminuria (>300 mg/d or >200 mcg/min) that is confirmed on at least 2 occasions 3-6 months apart, a relentless decline in the glomerular filtration rate (GFR), and elevated arterial blood pressure.