الفهرس 
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Abstract
Acute kidney injury:
Acute kidney injury, previously called acute renal failure , is an abrupt loss of kidney function that develops within 7 days. Its causes are numerous. Generally it occurs because of damage to the kidney tissue caused by decreased renal blood flow (renal ischemia) from any cause (e.g. low blood pressure), exposure to substances harmful to the kidney, an inflammatory process in the kidney, or an obstruction of the urinary tract which impedes the flow of urine. AKI is diagnosed on the basis of characteristic laboratory findings, such as elevated blood urea nitrogen and creatinine, or inability of the kidneys to produce sufficient amounts of urine. AKI may lead to a number of complications, including metabolic acidosis, high potassium levels, uremia, changes in body fluid balance, and effects to other organ systems. Management includes supportive care, such as renal replacement therapy, as well as treatment of the underlying disorder.
The symptoms of acute kidney injury result from the various disturbances of kidney function that are associated with the disease. Accumulation of urea and other nitrogen-containing substances in the bloodstream lead to a number of symptoms, such as fatigue, loss of appetite, headache, nausea and vomiting. Marked increases in the potassium level can lead to irregularities in the heartbeat, which can be severe and life-threatening. Fluid balance is frequently affected, though hypertension is rare. The construct of renal angina has been developed to assist with detection of early signs of kidney injury. Pain in the flanks may be encountered in some conditions (such as thrombosis of the renal blood vessels or inflammation of the kidney); this is the result of stretching of the fibrous tissue capsule surrounding the kidney. If the kidney injury is the result of dehydration, there may be thirst as well as evidence of fluid depletion on physical examination. Physical examination may also provide other clues as to the underlying cause of the kidney problem, such as a rash in interstitial nephritis and a palpable bladder.
AKI can be caused by disease, crush injury, contrast agents, some antibiotics, and more.The causes of acute kidney injury are commonly categorized into prerenal, intrinsic, and postrenal.
The deterioration of renal function may be discovered by a measured decrease in urine output. Often, it is diagnosed on the basis of blood tests for substances normally eliminated by the kidney: urea and creatinine. Both tests have their disadvantages. For instance, it takes about 24 hours for the creatinine level to rise, even if both kidneys have ceased to function. A number of alternative markers has been proposed (such as NGAL, KIM-1, IL18 and cystatin C), but none are currently established enough to replace creatinine as a marker of renal function. Use of the renal angina index, a composite of risk factors and early signs of injury, has been used to detect fulfillment of renal angina in children. Once the diagnosis of AKI is made, further testing is often required to determine the underlying cause. These may include urine sediment analysis, renal ultrasound and/or kidney biopsy.
The management of AKI hinges on identification and treatment of the underlying cause. In addition to treatment of the underlying disorder, management of AKI routinely includes the avoidance of substances that are toxic to the kidneys, called nephrotoxins. These include NSAIDs such as ibuprofen, iodinated contrasts such as those used for CT scans, many antibiotics such as gentamicin, and a range of other substances. Monitoring of renal function, by serial serum creatinine measurements and monitoring of urine output, is routinely performed. In the hospital, insertion of a urinary catheter helps monitor urine output and relieves possible bladder outlet obstruction, such as with an enlarged prostate.
Acute kidney injury in ICU:
Incidence of AKI among critically ill patients was high. Hypovolaemia, diuretics, and colloids prior to ICU admission were independently associated with the development of AKI. In this population, urine NGAL was statistically associated with the need to initiate RRT, but the transformation of this result into clinical practice is complicated. Urine NGAL lacks power to predict AKI or 90-day mortality. Urine IL-18 has no adequate power to predict AKI, RRT, or 90-Day mortality in critically ill adult patients. AKI is associated with significantly increased 90-day and 6-month mortality. The HRQol of all ICU patients was lower than that of the age- and sex-matched general population already before ICU treatment. This HRQol did not change during critical illness or during a six-month follow up. Despite their lower HRQol, AKI patients felt their health was equal to that of the general population.