Nephrotic syndrome: causes, signs and symptoms
General Information
Nephrotic syndrome is a condition characterised by abnormally high levels of protein in the urine (proteinuria). This syndrome is a common clinical feature of a variety of diseases that affect the normal working of the glomeruli (singular = glomerulus). A glomerulus is a tiny bunch of capillaries in the kidney that acts as a filter to remove waste products from the blood. The waste products then go on to be excreted from the body in the urine. There are about one million glomeruli in each kidney. In healthy people only tiny amounts of protein appear in the urine. Nephrotic syndrome causes the glomeruli to become defective, allowing large quantities of protein to be lost in the urine.Causes
In New Zealand, the most common cause of the nephrotic syndrome is primary glomerulonephritis. Glomerulonephritis is the term used to describe a group of kidney diseases where the glomeruli are inflamed. Malfunction of the immune system that protects the body from disease is thought to be the underlying cause of glomerulonephritis. Most forms of glomerulonephritis are not known to be preventable. The three most important forms of glomerulonephritis causing the nephrotic syndrome are minimal change nephropathy, membranous glomerulonephritis and focal sclerosing glomerulonephritis. A wide range of other disorders and toxins (including diabetes mellitus and lupus) are less common causes of the nephrotic syndrome.In children, the nephrotic syndrome is normally detected between the age of 3 and 4 years old. The majority of children have the form of glomerulonephritis called minimal change nephropathy. This is where minimal or no glomerular abnormalities are noted by a microscope. It can usually be successfully treated. In adults, membranous glomerulonephritis and focal sclerosing glomerulonephritis are the most common causes of the nephrotic syndrome.
