6.3.5　Renal Failure

Renal failure refers to a condition in which the kidneys stop functioning and do not produce urine.There is a rapid loss of kidney function with oliguria and accumulation of nitrogenous wastes in the blood.When destruction（necrosis）of kidney tubules is involved，the condition may be referred to as acute tubular necrosis（ATN）.Accidents，injuries，shock，exposure to toxins，infections，and drug overdoses may cause the onset of acute renal failure（ARF）.In chronic renal failure，there is a progressive irreversible deterioration in renal function in which the body’s ability to maintain metabolic，fluid，and electrolyte balance fails.A gradual progression toward uremia occurs.The most common causes of chronic renal failure are hypertension and diabetes.

The symptoms of end-stage renal failure include nausea，vomiting，anorexia，and hiccups.Numbness and burning sensations in both legs and feet are common，with prickly sensations being more intense at night.Anemia is present due to the kidney’s suppressed secretion of erythropoietin，which stimulates the production of red blood cells in the bone marrow.Hypertension is usually present and may require antihypertensive therapy to control blood pressure.The patient may also experience pruritus，polyuria，weight loss，lack of energy，pale skin with a sallow or brownish hue，and mental confusion.

Renal failure may lead to a need for kidney dialysis or，ultimately，renal transplantation.In hemodialysis，blood is cleansed by passage over a membrane surrounded by fluid（dialysate）that draws out unwanted substances.In peritoneal dialysis，fluid is introduced into the peritoneal cavity.The fluid is periodically withdrawn along with waste products and replaced.(https://www.daowen.com)

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Task 7　Write a word with each of the following meanings.