What is end-stage renal disease?

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Stage 5 of chronic kidney disease, which causes irreversible damage to and near-complete failure of the kidneys.
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Causes and Symptoms

End-stage renal disease (ESRD) is stage 5 of chronic kidney disease, defined as kidney function at less than 10 percent of normal and a glomerular filtration rate of less than 15 milliliters per minute. Both diseases are characterized by the inability to remove wastes and concentrate urine, have poor outcomes, and are usually the result of long-standing diabetes and/or uncontrolled hypertension.

ESRD is a serious, life-threatening systematic disease characterized by renal failure, decreased production of red blood cells and active vitamin D3, and excess excretion of acid, potassium, salt, and water. Many metabolic abnormalities and imbalances occur, causing complications, such as anemia, acidemia or acidosis, hyperkalemia, hyperphosphatemia, hyperparathyroidism, and hypocalcemia. Symptoms include swollen feet and ankles, fatigue, lethargy or weakness, itching, skin color changes, loss of mental alertness, shortness of breath, and recurrent or chronic heart failure.

Tests that measure the level of creatinine and urea in blood and urine are conducted to determine the extent of kidney damage and the filtration capacity of the kidneys. High levels of these waste products found in the blood but not in the urine are signs of kidney damage. ESRD may be suspected when very high levels of protein are detected in the urine (proteinuria). The results of a creatinine clearance are used to determine the glomerular filtration rate, the standard measurement used to assess kidney function.

Diabetes mellitus is the most common cause of ESRD, due to its underlying kidney disease—diabetic nephropathy. Approximately 20 to 40 percent of patients with diabetes develop the disease, and nearly half of them progress to ESRD within five to ten years. Diabetic nephropathy develops with changes in the microvasculature (tiny blood vessels) of the glomerulus and is characterized by a progressive and aggressive disease course: wastes increase, building up in the blood; kidneys leak larger amounts of albumin, causing proteinuria; and nodular glomerulosclerosis lesions proliferate and destroy the glomeruli.

Hypertension (high blood pressure) is a major cause of ESRD, estimated at approximately 30 percent of all cases. Although arteries are elastic, they can become overstretched from hypertension and narrow, weaken, or harden. This is especially deadly in the kidneys, which are highly vascular and carry large volumes of blood. Damaged blood vessels and filters prevent the kidneys from functioning adequately, including reducing the hormone that they normally produce to help the body regulate its own blood pressure. Thus, hypertension is both a cause and a symptom of ESRD.

Uremia is a syndrome that develops with ESRD when metabolic, fluid, electrolyte, and hormone imbalances emerge concurrently. Clinical symptoms include nausea or vomiting, fatigue, weight loss, muscle cramps, pruritus (itching), mental status changes, visual disturbances, and increased thirst.

Renal osteodystrophy is a degenerative bone disease that develops with metabolic imbalances in the minerals phosphorus and calcium. High levels of phosphorus in the blood draw calcium out of the bones, causing them to become brittle and break. The excess of phosphorus and calcium salts in the blood deposit and harden, forming metastatic calcifications in the skin, blood vessels, and other soft tissues.

Treatment and Therapy

Dialysis and kidney transplantation are the only treatments for ESRD and provide a means of prolonging a patient’s life span and maintaining quality of life.

Dialysis is a means of cleansing the blood when the kidneys do not function and is done by the process of diffusion, in which blood is passed through a filter in contact with a dialysate (salt solution), separating the smaller molecules (solute particles) from the larger molecules (colloid particles). There are two types of dialysis—hemodialysis and peritoneal dialysis—each of which has several variants.

In hemodialysis, blood is filtered by diverting it outside the body through a fistula and flows across a semipermeable membrane in the dialysis unit in a direction countercurrent to the dialysate. Hemodialysis takes three to four hours to complete and must be done three to five times a week, usually in a dialysis clinic. In peritoneal dialysis, blood is filtered internally through the peritoneum, a thin membrane inside the abdomen and peritoneal dialysis fluid is infused into the cavity via a catheter. Exchanges are repeated four to six times a day by the patient, and the process must be done every day.

Kidney transplants are another option for most ESRD patients. The United Network for Organ Sharing recommends that patients be put on the cadaveric renal transplant list when their glomerular filtration rate is less than 18 milliliters per minute. Improvements in their policies provide for a more equitable allocation system, broaden the classification of expanded donor criteria, and are expected to increase the donor pool. Unfortunately, thousands of patients die each year waiting for an available kidney.

Perspective and Prospects

Chronic kidney disease and ESRD represent a growing public health problem and reflect the disturbing health profile of present-day society—rising numbers of people with obesity, diabetes, hypertension, cardiovascular disease, and metabolic syndrome. The prevalence of chronic kidney disease has risen steadily since the 1980s. Changes in lifestyle and increased awareness of disease risk—including the monitoring of one's blood sugar levels and blood pressure—are key to preventing chronic kidney disease and reducing the number of patients who progress to ESRD.

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