Kidney Diseases (General)

The bean-shaped kidneys, which are roughly the size of a human fist, lie on either side of the body in the middle of the back, just beneath the rib cage. Within each kidney, there are a million functioning units known as nephrons, which perform the vital functions of balancing concentrations of water, ions, salt, acids, potassium, and calcium in the body and removing contaminants from the blood stream. This balancing function also involves synthesizing, modifying, and secreting hormones and vitamins that influence other body functions. The kidney helps to regulate blood pressure and stimulates the formation of red blood cells. In a single day, around 200 quarts of fluid [Page 972]are filtered through the kidneys. Blood is received in the kidney from the renal artery, and filtered blood is returned to the body through the renal veins. Every day, around two quarts of waste fluids are channeled into the bladder where they are subsequently eliminated through the urethra as urine.

Great progress in understanding kidney functions and diseases has taken place since the end of World War II. Increased research funding has been essential to this progress, and has precipitated advances in renal anatomy and physiology, biochemistry, pharmacology, bioenergetics, molecular, cell, and development biology, genetics and genomics. Physicians are now able to draw on new knowledge and technologies to deal with kidney diseases and injuries that would have proved fatal in the past. One of the most significant successes has been in the field of kidney transplants. The human genome project continues to provide researchers with great insight into the role of inheritance in the development of kidney diseases. Johns Hopkins University maintains an extensive online database of genetic aspects of kidney disease.

When any aspect of essential kidney functions fails to operate properly, kidney diseases develop. The six warning signs of kidney disease are: burning or difficult urination, increased frequency of urination, bloody urine, puffiness around the eyes, swelling of the hands and feet, pain in the small of the back, and high blood pressure. Important factors in preventing kidney disease are controlling hypertension, maintaining a healthy weight, reducing salt intake, eating foods containing calcium and potassium, being physically active, and avoiding excess alcohol intake.

The four major causes of kidney failure are diabetes, hypertension, glomerulonephritis, and polycystic disease. It is estimated that 20 million Americans suffer from kidney or urinary tract-related diseases. African-Americans are at higher risk than others for all incidences of kidney disease except polycystic disease. They are 20 times likelier than other Americans to develop kidney disease that results from hypertension. African-Americans also tend to develop kidney diseases at earlier ages than white Americans. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) is currently involved in a research initiative to develop a greater understanding of kidney disease in African-Americans.

While some disorders such as kidney stones may affect only one kidney, most kidney diseases are bilateral. Kidney diseases range from minor infections to progressive kidney failure. Approximately 100,000 Americans with kidney disease require dialysis or a kidney transplant. During dialysis, artificial kidneys take over the role of filtering the blood and returning cleansed blood to the body. While the process keeps kidney patients alive, it is not with side effects. Dialysis patients are prone to blood clots and infections. Patients new to dialysis may develop headaches, nausea, muscle cramps, anorexia, dizziness, and seizures. A 1998 study revealed that 86 percent of African-Americans with kidney failure were on dialysis as opposed to 69 percent of Whites. A number of studies have shown that African-Americans tend to remain on dialysis, in part because they tend to have fewer complications and are likely to live longer than white dialysis patients. Advances in kidney transplants have been instrumental in removing hundreds of thousands of patients from dependence on dialysis and restoring quality of life despite the continued need for immunosuppressive drugs.

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