Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Kidneys are the organs that help filter waste products from the blood. They
are also involved in regulating blood pressure, electrolyte balance, and red
blood cell production in the body.
There are numerous causes of kidney failure, and treatment of the
underlying disease may be the first step in correcting the kidney abnormality.
Some causes of kidney failure are treatable and the kidney function may
return to normal. Unfortunately, kidney failure may be progressive in other
situations and may be irreversible.
Symptoms of kidney failure are due to the build-up of waste products in the
body that may cause weakness, shortness of breath, lethargy, and confusion.
Inability to remove potassium from the bloodstream may lead to abnormal heart
rhythms and sudden death. Initially, there may be no symptoms of kidney failure.
The diagnosis of kidney failure usually is made by blood tests measuring
BUN, creatinine, and glomerular filtration rate (GFR).
Treatment of the underlying cause of kidney failure may return kidney
function to normal. Lifelong efforts to control blood pressure and diabetes may
be the best way to prevent chronic kidney disease and its progression to kidney
failure. Usually, kidney function gradually decreases over time.
If the kidneys fail completely, the only treatment options available may be
dialysis or transplant.
What are the kidneys?
The kidneys play key roles in body function, not only by filtering the blood
and getting rid of waste products, but also by balancing levels of
electrolyte levels in the body, controlling blood pressure, and stimulating the
production of red blood cells.
The kidneys are located in the abdomen toward the back, normally one on each
side of the spine. They get their blood supply through the renal arteries
directly from the aorta and send blood back to the heart via the renal veins to
the vena cava. (The term "renal" is derived from the Latin name for kidney.)
The kidneys have the ability to monitor the amount of body fluid, the
concentrations of electrolytes like sodium and potassium, and the acid-base
balance of the body. They filter waste products of body metabolism, like urea
from protein metabolism and uric acid from DNA breakdown. Two waste products in
the blood can be measured: blood urea nitrogen (BUN) and
When blood flows to the kidney, sensors within the kidney decide how much
water to excrete as urine, along with what concentration of electrolytes. For
example, if a person is dehydrated from
exercise or from an illness, the kidneys
will hold onto as much water as possible and the urine becomes very
concentrated. When adequate water is present in the body, the urine is much more
dilute, and the urine becomes clear. This system is controlled by renin, a
hormone produced in the kidney that is part of the fluid and blood pressure
regulation systems of the body.
Kidneys are also the source of erythropoietin in the body, a hormone that
stimulates the bone marrow to make red blood cells. Special cells in the kidney
monitor the oxygen concentration in blood. If oxygen levels fall, erythropoietin
levels rise and the body starts to manufacture more red blood cells.
After the kidneys filter blood, the urine is excreted through the ureter, a
thin tube that connects it to the bladder. It is then stored in the bladder
awaiting urination, when the bladder sends the urine out of the body through the
Reviewed by Melissa Conrad Stöppler, MD on 2/4/2013
Kidney disease is often called a "silent" disease, because most people have no symptoms before they are diagnosed. In fact, you might feel just fine until your kidneys have almost stopped working. Do NOT wait for symptoms!