Some patients define their disease in generalities, saying that they have poor kidney function or that they have bad kidneys. This information is inadequate because there are many different causes of poor kidney function. Knowing the cause of poor kidney function--also called renal function--provides important insight into how fast the renal disease will progress and if there are other medical concerns of which the patient should be aware.
Expert Insight
According to the United States Renal Data System 2007 Annual Data Report, diabetes is the leading cause of poor kidney function. The National Institutes of Health notes that even when diabetes is controlled, it can lead to a form of chronic kidney disease called diabetic nephropathy. Since poor kidney function is invariably progressive when associated with diabetes, persons with diabetes who have poor kidney function are at risk for renal failure.
While many of the 24 million people with diabetes will never develop renal failure, the 2007 Annual Data Report indicates that diabetes accounts for 44 percent of cases of renal failure.
Risks
High blood pressure, also called hypertension, is the second leading cause of renal failure. Mayoclinic.com notes that it can cause "weakened and narrowed blood vessels" in the kidneys. Hypertension is particularly insidious because unless people regularly monitor their blood pressure, they may be unaware of this problem until it causes other issues such as poor kidney function.
Once a patient is identified as hypertensive, prompt treatment and lifestyle changes, if appropriate, can help minimize the risk to the patient's kidneys. Continued blood pressure monitoring helps prevent future problems.
Prevention
Knowing the particular cause of poor kidney function also allows one to work proactively to minimize the side effects of particular diseases. This is particularly true with glomerular diseases, which are the third most common cause of renal failure in the United States. This category of disorders includes a number of different conditions that affect the glomeruli, also referred to as the filters in the kidney. These conditions include IgA nephropathy, FSGS, MPGN, membranous nephropathy, mesangial nephopathy, Alport's syndrome and many others.
Patients with some of these diseases can be at risk for other disorders. For example, patients with Alport's often have hearing problems, and patients with MPGN-2 are at risk for vision problems caused by deposits on the retina. If patients know the specific cause of their kidney problem, they are in a better position to monitor for such problems and treat them if they arise.
Prenatal Screening
Prenatal screening can identify congenital kidney disorders that are present during development. For example, various congenital disorders such as renal dysplasia and hydronephrosis that cause poor renal function in children can be diagnosed through prenatal ultrasound.
Congenital disorders often involve developmental problems in which the fetal kidney did not develop properly or structural issues, such as an obstruction, that can be corrected surgically after birth. The University of Alberta reports that the renal function of some of these babies is so poor that they are born requiring dialysis. However, many others grow normally and do not experience impaired renal function until later in childhood.
Diagnostic Work-up
In many instances, the diagnostic workup for kidney disease is brief and does not even require a biopsy. For example, patients with diabetes are rarely biopsied. In other instances, symptoms such as high urine protein may be so mild that the doctor may not feel that a biopsy is worth it at the present time.
For other patients, particularly those with glomerular disease, biopsy is necessary to determine the specific cause of their poor renal function. Although many people are initially fearful of renal biopsy, the procedure it is not particularly painful and most people are back at work the following day.
