Kidneys filter your blood all the time through thousands of tiny filters called glomeruli. Your kidneys know what should stay in your blood and what should go into your urine. There is protein in your blood, but very little should get into your urine. If too much protein happens to get into your urine, it is called proteinuria. Doctors can determine if there is protein in your urine by putting a special dipstick into a urine sample or, for a more precise measurement of protein, a laboratory can do it.
The kidneys make urine all the time, and it collects in your bladder until you need to empty it. Some people put more protein in their urine when standing, but not when they are lying down (postural proteinuria). This is not associated with any long-term kidney problems. Protein can be measured from a urine sample that was made while you were upright or lying down. Small amounts of protein can also be found in the urine in normal people after very hard exercise.
When reasons can't be found for protein in your kidneys, there may be problems with the filters or with the kidney drainage system (urinary tract). If there is a problem with the urinary tract, you will need to see a pediatric urologist, who is a kidney and urinary tract surgeon.
A medical kidney specialist for children is called a Pediatric Nephrologist. Medical disease of the filters can be divided into two main groups; One group leaks primarily protein while the other leaks mostly blood. In the protein group, the name of the kidney condition depends on what the filters look like. Names like Minimal Change Disease, Focal Segmental Glomerulosclerosis, Mesangial Nephropathy, or Membranous Nephropathy are used to describe them. The blood group is called glomerulonephritis.
Loss of protein from the blood into urine can cause imbalanced body fluids, making the body swell. This problem is called the Nephrotic Syndrome. Minimal Change Disease is the most common type of filter problem seen in nephrotic syndrome. This means that the glomeruli look nearly normal. The glomeruli can only be seen by looking at a tiny piece of kidney under a microscope. The other types of filter problems have abnormal filter patterns and are more serious. In these more serious cases, there is potential for a decrease in kidney function. Nephrotic syndrome may occur in these types too, but responses to treatment may not be as good. If the amount of proteinuria isn't too much and all other tests are normal, treatment may not be needed right away. The proteinuria may decrease by itself. However, if your child has nephrotic syndrome, treatment is usually necessary.
Visits to The Kidney Center may include urine and blood tests and X-rays to see how your kidneys are working. Blood pressure is checked because sick kidneys can high blood pressure. The doctor will also want to know if your child has any swelling. Tests are repeated to see how well the kidneys are doing and if there are any problems related to the protein loss. Checking kidney function is very important, because if the kidneys get too sick, you may have kidney failure.