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Query: UMLS:C0022672 (acute tubular necrosis)
 2,175 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The computed radionuclide urogram is advocated as a noninvasive diagnostic method for differentiation of the most common prerenal, renal, and postrenal causes of acute renal failure. On the basis of characteristic changes in the effective renal plasma flow rate, the calculated filtration fraction, and the calculated glomerular filtration rate, prerenal conditions such as renal artery stenosis or thrombosis, renal conditions such as acute rejection or acute tubular necrosis, and postrenal conditions such as obstruction or leakage, which are the most common causes of acute renal failure, can be differentiated. In conjunction with morphologic criteria derived from sonograms, a diagnosis with acceptable confidence can be rendered in most instances. Both the computed radionuclide urogram and sonogram are noninvasive and can be used without adverse effects in the presence of azotemia and even anuria. This also makes feasible reexamination at intervals to assess effect of therapy and offer prognostic information.
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PMID:Computed radionuclide urogram for assessing acute renal failure. 676 41

The use of 131I-orthiodohippurate (OIH) scintigraphy combined with the estimated renal plasma flow (ERPF) and excretion index (EI) has been beneficial in separating impaired renal function due to graft rejection from acute tubular necrosis, ureteral obstruction, urinary extravasation and in some instances renal artery occlusion. The radionuclide data accurately identified acute and chronic rejection, confirmed by the clinical course, increase in BUN and serum creatinine and on occasion renal biopsy. Reversible and irreversible acute tubular necrosis (ATN) were clearly differentiated from acute rejection. When the ERPF and EI were plotted on a graph, multiple sequential radionuclide studies accurately predicted graft survival when chronic rejection existed. The limitation of this technique was the inability to discriminate between renal artery stenosis, ureteral obstruction and inflammatory disease. Scintigraphic studies did not distinguish between renal artery stenosis and chronic rejection. In these circumstances arteriography was the diagnostic procedure of choice. Although ureteral obstruction often can be correctly diagnosed by scintigrams, the ERPF, EI and intravenous pyelogram remained the most accurate diagnostic procedures. Recurrent glomerulonephritis, gram negative septicemia and generalized viral illness (herpes zoster or cytomegalovirus) simulated acute rejection and had to be separated by renal biopsy or the clinical course. The most valuable features of the radionuclide technique included: 1) the noninvasive method, 2) the simplicity, 3) the rapidity and 4) the reproducibility.
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PMID:Diagnosis of impaired renal function after kidney transplantation using renal scintigraphy, renal plasma flow and urinary excretion of hippurate. 698 32

The urographic nephrogram is an important indicator of underlying functional and structural renal disease. With expansions in use of cross-sectional imaging, the computed tomographic (CT) nephrogram (ie, contrast material enhancement within the renal parenchyma) has assumed a greater role in the evaluation of urinary tract disorders. Both quantitative and qualitative nephrographic abnormalities are well demonstrated by CT, including global or segmental absence or persistence of the nephrogram, slowed temporal progression, striated pattern, and rim pattern. Global absence is nearly always unilateral and is most often seen with blunt abdominal trauma with renal pedicle injury. Segmental absence is attributable to focal renal infarction, most likely due to arterial emboli. Global persistence, which is much more common than segmental persistence, may be unilateral (caused by renal artery stenosis, renal vein thrombosis, or urinary tract obstruction) or bilateral (due to systemic hypotension, intratubular obstruction, or abnormalities in tubular function). Striated nephrograms may be unilateral or bilateral and are caused by ureteric obstruction, acute pyelonephritis, contusion, renal vein thrombosis, tubular obstruction, hypotension, and autosomal recessive polycystic kidney disease. The rim pattern is most often associated with renal infarction and occasionally with acute tubular necrosis and renal vein thrombosis. Careful evaluation of the CT nephrogram is an integral part of the abdominal CT examination.
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PMID:The CT nephrogram: implications for evaluation of urinary tract disease. 750 51

The incidence of renal failure due to vascular diseases is increasing. Two reasons for this are the epidemic of atherosclerotic vascular disease in the aging population and the widespread use of vasoactive drugs that can adversely affect renal function. These vascular causes of renal failure include vasomotor disorders such as that associated with nonsteroidal antiinflammatory drugs, small-vessel diseases such as cholesterol crystal embolization, and large-vessel diseases such as renal artery stenosis. These causes of azotemia are less familiar to physicians than more classic causes, such as acute tubular necrosis, and are less likely to be recognized in their early stages. This article describes the various vascular diseases that impair renal function and outlines the steps necessary to identify them. Although some of these conditions, such as renal artery stenosis, can gradually impair function, the vascular causes of acute renal failure are emphasized in this article. Because the vasculitides primarily cause renal failure through secondary glomerulonephritis, they are mentioned only briefly. Extensive testing is rarely necessary because the cause is usually suspected through syndrome recognition. The diagnosis can then be confirmed by the results of one or two additional tests or by improved renal function after treatment.
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PMID:Diagnosing vascular causes of renal failure. 867 77

We report two cases of acute renal failure in renal transplant patients using cyclosporine-A (CsA) after the introduction of angiotensin-converting enzyme inhibitor (ACEI) to control arterial hypertension. They had no renal artery stenosis or acute rejection. Both patients presented severe acute tubular necrosis (ATN), which subsided after discontinuation of the ACEI. Synergistic toxic effect of ACEI and CsA on the renal tubules might explain ATN in these two cases.
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PMID:Acute tubular necrosis in kidney transplant patients treated with enalapril. 805 25

Renal failure following transplantation can be classified in two groups: initial non function characterized by the absence of renal function after transplantation and delayed secondary non function after an initial improvement. In the first group, the most frequent etiology is an acute tubular necrosis (30 to 50% of the cases) which usually heals within three weeks. Arterial thrombosis are rare but of very bad prognosis. In the second group, the most frequent cases are acute rejection, urological complications, renal artery stenosis, urinary infections and cyclosporine, intoxication. Diagnostic imaging, and especially the color Doppler flow, is very effective in obtaining diagnosis. Vascular or urological complications are to be confirmed by contrasted opacifications. In the absence of vascular or urological obstruction renal failure must be related to a renal parenchymal disease. This may be acute tubular necrosis, a rejection, a pyelonephritis or a medicinal intoxication depending on clinical symptoms, the time of their apparition and the results of biological examinations.
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PMID:[The transplanted kidney. Role of imaging in early non-functioning grafts]. 815 35

Renal allografts are subject to many vascular complications. Doppler US is a non-invasive technique that can evaluate many of the potential complications related to renal allografts, such as rejection, cyclosporine toxicity, acute tubular necrosis, renal artery stenosis, renal vein thrombosis. Changes in the resistive index (RI), which accurately reflects renal vascular impedance, have been employed in the evaluation of renal allograft dysfunction. A review of the literature shows conflicting results with values of sensitivity and specificity ranging from 0.96 and 0.97 to 0.46 and 0.80, respectively. It seems that an increase in the RI is a nonspecific sign in determining the underlying abnormality due to the unique features of the vascular bed of each allograft which results in poor correlative values for single isolated measurements of RI. Serial studies, employing a baseline value, can be useful in the follow-up of graft dysfunction.
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PMID:[Role of echo-color Doppler in the monitoring of the transplanted kidney]. 833 17

Color flow mapping and duplex ultrasonography are a more accurate technique in renal allograft monitoring by combining real time us with pulsed doppler studies of renal vasculature. Doppler spectral analysis, pulsatility and resistive index evaluation are usefull in the diagnosis of renal allograft dysfunction (I.E. rejection, cyclosporine nefroto-city and acute tubular necrosis). Cfm and duplex ultrasonography allow a non invasive and easy evaluation of the whole renal artery and vein in the diagnosis of renal artery stenosis, vein trombosys and A-V fistula.
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PMID:[Role of color flow mapping ultrasonography in kidney transplant monitoring]. 876 7

Angiotensin converting enzyme (ACE) inhibitors are useful in the treatment of hypertension and heart failure. However, acute renal failure (ARF) may occur in patients who are taking these drugs in situations associated with decreased glomerular filtration pressure, such as dehydration caused by acute diarrhea or diuretic therapy. Sixty-four patients who were admitted to the intensive care unit for ARF associated with ACE inhibitor therapy were followed for more than 5 years. In this historical retrospective study, we documented that 45 patients were treated for hypertension (group I) and 19 were treated for heart failure (group II). Their mean age was 71.2+/-11.6 years. Patients with ARF presented with overt dehydration in 91% and 84% of the cases in groups I and II, respectively. Hypovolemia was caused by diuretics or gastrointestinal fluid loss. Bilateral artery-renal stenosis or stenosis in a solitary kidney was documented in 22% and 10% of patients in groups I and II, respectively. The probability of survival was 91% and 49% at 1 year and 64% and 18% at 5 years, for groups I and II, respectively. Acute renal failure required hemodialysis in seven patients, but none of them became dialysis dependent. In the subgroup of patients with preexisting chronic renal failure, all the patients except for one who belonged to group II died within 2 years. In both groups, after resolution of ARF, plasma creatinine concentration returned to baseline level and the course of renal function was not significantly worsened. In conclusion, ARF associated with ACE inhibitors is likely to occur in many patients without renal artery stenosis after unexpected dehydration, especially in older patients with congestive heart failure. In both groups of patients, in the absence of preexisting chronic uremia, recovery of renal function occurred without sequelae, even after an episode of acute tubular necrosis requiring dialysis.
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PMID:Long-term follow-up of acute renal failure caused by angiotensin converting enzyme inhibitors. 1056 Jul 94

Comprehensive evaluation of renal transplants has been important in differential diagnosis of medical and surgical complications in the early post-transplantation period and in the long-term follow-up. If performed well, it yields excellent functional and good anatomic information about the graft that can be effectively used in the patient. That includes selection of patients for biopsy and for various drug regimens. This is true especially in patients with anuric acute tubular necrosis (ATN) and in patients with developing chronic rejection. Improving indices of renal function (effective renal plasma flow, uptake of tubular tracers) can indicate resolution of tubular injury (ATN) while there is still no improvement in plasma creatinine. In patients with chronic rejection, plasma creatinine increases only after approximately 30% of renal function is lost due to graft fibrosis. Early recognition of this condition could permit treatment and delay of retransplantation. The protocol recommended at the Copenhagen meeting includes a flow study, scintigram of the kidneys, prevoid and postvoid bladder image, injection site image (quality control), time/activity curves of the graft and bladder, and quantitative data of perfusion, function, and tracer transit. The flow study obtained during the initial transit of the bolus through the graft could be performed either with 99mTc mercaptoacetyltriglycine, or 99mTc diethylenetriaminepentaacetate (DTPA). Quantitative analysis of perfusion facilitates interpretation of the study during the early post-transplantation period. ATN, common in cadaver transplants, typically shows adequate perfusion. The function phase should include images and time/activity curves. Images alone are insufficient. Quantitative data such as clearance or other indices of function and indices of tracer transit are essential for correct interpretation of the results. Normal images and normal graft function reliably exclude clinically important complications. A single scintigram demonstrating prolonged tracer transit with decreased function cannot separate acute rejection and ATN. On serial studies, decline in function and poor perfusion are indicative of acute rejection. A normally appearing scintigram without cortical retention, but with low function, is consistent with chronic rejection. Pharmacological intervention to exclude obstruction (diuretic renogram) or hemodynamically significant renal artery stenosis (angiotensin converting enzyme challenge) should be used whenever indicated.
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PMID:Report of the Radionuclides in Nephrourology Committee for evaluation of transplanted kidney (review of techniques). 1032 28


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