The Kidneys And How They Work?

Preparing for End-stage Renal Disease (ESRD)

As kidney disease progresses, a person needs to make several decisions. People in the later stages of CKD need to learn about their options for treating the last stages of kidney failure so they can make an informed choice between hemodialysis, peritoneal dialysis, and transplantation.

What happens if the kidneys fail completely?

Total or nearly total and permanent kidney failure is called ESRD. If a person’s kidneys stop working completely, the body fills with extra water and waste products. This condition is called uremia. Hands or feet may swell. A person will feel tired and weak because the body needs clean blood to function properly.

Untreated uremia may lead to seizures or coma and will ultimately result in death. A person whose kidneys stop working completely will need to undergo dialysis or kidney transplantation.


The two major forms of dialysis are hemodialysis and peritoneal dialysis. Hemodialysis uses a special filter called a dialyzer that functions as an artificial kidney to clean a person’s blood. The dialyzer is a canister connected to the hemodialysis machine. During treatment, the blood travels through tubes into the dialyzer, which filters out wastes, extra salt, and extra water. Then the cleaned blood flows through another set of tubes back into the body. The hemodialysis machine monitors blood flow and removes wastes from the dialyzer. Hemodialysis is usually performed at a dialysis center three times per week for 3 to 4 hours. A small but growing number of clinics offer home hemodialysis in addition to standard in-clinic treatments. The patient first learns to do treatments at the clinic, working with a dialysis nurse. Daily home hemodialysis is done 5 to 7 days per week for 2 to 3 hours at a time. Nocturnal dialysis can be performed for 8 hours at night while a person sleeps. Research as to which is the best method for dialysis is under way, but preliminary data indicate that daily dialysis schedules such as short daily dialysis or nocturnal dialysis may be the best form of dialysis therapy.

Figure 3. Hemodialysis


In peritoneal dialysis, a fluid called dialysis solution is put into the abdomen. This fluid captures the waste products from a person’s blood. After a few hours when the fluid is nearly saturated with wastes, the fluid is drained through a catheter. Then, a fresh bag of fluid is dripped into the abdomen to continue the cleansing process. Patients can perform peritoneal dialysis themselves. Patients using continuous ambulatory peritoneal dialysis (CAPD) change fluid four times a day. Another form of peritoneal dialysis, called continuous cycling peritoneal dialysis (CCPD), can be performed at night with a machine that drains and refills the abdomen automatically.

Figure 4. Peritoneal dialysis


A donated kidney may come from an anonymous donor who has recently died or from a living person, usually a relative. The kidney must be a good match for the patient’s body. The more the new kidney is like the person receiving the kidney, the less likely the immune system is to reject it. The immune system protects a person from disease by attacking anything that is not recognized as a normal part of the body. So the immune system will attack a kidney that appears too “foreign.” The patient will take special drugs to help trick the immune system so it does not reject the transplanted kidney. Unless they are causing infection or high blood pressure, the diseased kidneys are left in place. Kidneys from living, related donors appear to be the best match for success, but kidneys from unrelated people also have a long survival rate. Patients approaching kidney failure should ask their doctor early about starting the process to receive a kidney transplant.

Figure 5.


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