Kidneys are constantly filtering your blood. Thousands of tiny filters (glomeruli) in each kidney know what should stay in your blood and what should pass through as urine. If too much protein gets into your urine it is called proteinuria. Protein can be found in the urine by putting a special dipstick into a sample or by sending a sample to a laboratory to be measured.
The loss of protein from blood into urine can be so much that the amount of protein in the blood gets too low. When this happens, some of the fluid that makes up the blood leaks into the tissues, causing parts of the body to swell. This is called the nephrotic syndrome. Nephros means "kidney-related" in Greek. Your doctor may get advice from or refer you to a pediatric kidney specialist called a pediatric nephrologist.
Eighty-five percent of children with nephrotic syndrome have Minimal Change Disease. With Minimal Change Disease, filters look nearly normal and protein loss responds well to treatment. Since eighty-five percent is a large number, this is suspected most of the time without having to look at the filters through a microscope. Focal Segmental Glomerulosclerosis, Mesangial Nephropathy, and Membranous Nephropathy are the names used to describe cases with abnormal filter patterns. They are more serious and in some cases, a decrease in kidney function may occur. If these are suspected, a kidney biopsy may be needed. Nephrotic Syndrome can occur in these types too, but response to treatment may not be as good.
With treatment, proteinuria may stop (remission), change very little, or not at all. In some cases, it may even get worse. If it goes away and then comes back needing treatment, it is called a relapse. This can happen frequently but everyone is different in terms of how often they have a relapse. Treatment such as the medication prednisone, a medical steroid, is prescribed because losing protein causes more serious problems than just looking swollen. Nephrotic Syndrome can also cause increased risk of certain kinds of infection (due to urine loss of antibodies) or increased risk of blood clots (due to urine loss of anti-clotting proteins). Other medicines may be prescribed if your child is not responding to the prednisone or if the effects of the prednisone are not lasting.
While waiting for the medicines to stop the protein leak, swelling may be a problem, so diuretics are prescribed to make the kidneys produce urine and reduce swelling. At times it may even be necessary to replace protein in the blood through an IV. These steps temporarily adjust the fluids but they don't treat the kidneys themselves. Medicines may also be needed for other complications, like infection or high blood pressure.
Visits to the Kidney Center may involve urine and blood tests and X-rays to see how your kidneys are working. Blood pressure is checked because sick kidneys can cause high blood pressure. The doctor will want to know if you have any swelling. Your nephrologist may discuss if there is any need for a biopsy. Testing will be repeated as long as the problem continues. Nephrotic Syndrome is tough, but the kidneys can still work. However, your kidneys always need to be watched for any decrease in function.