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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 pathogenesis of acute renal failure (ARF) in such common conditions as acute tubular necrosis, acute interstitial nephritis, and primary graft anuria (ischemic transplant ARF) is poorly understood. Animal models may not exactly mimic the situation in man and thus human morphologic studies are of particular importance. Non-replacement of individual sloughed tubular cells and simplification of the brush border and basolateral infoldings of tubular cells are prominent morphologic changes which correlate with the presence of renal failure. It is possible that the initial injury inhibits cell membrane synthesis, thus interfering with proximal tubular sodium reabsorption with resulting activation of the renin angiotensin system and afferent arteriolar vasoconstriction. Tubular backleak, tubular obstruction by casts and debris, and decreased glomerular ultrafiltration coefficient may also play a role. Although poorly studied until now, the renal failure in primary graft anuria may have a completely different pathogenesis from that in acute tubular necrosis and acute interstitial nephritis. Cyclosporine nephrotoxicity is an important component of primary graft anuria, as seen in many transplant centers in the 1980's.
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PMID:Acute renal failure in man: pathogenesis in light of new morphological data. 330 Nov 19

Renal hypoperfusion such as occurs in shock creates an environment in which cellular injury and organ dysfunction can occur during the episode of shock as well as during reoxygenation and reperfusion. A severe decrement in oxygen delivery compromises energy (adenosine triphosphate) production, leading to various degrees of cell injury ranging from cell swelling to acute cortical necrosis. These different responses of the kidney to shock explain the multiple clinical presentations varying from an isolated loss of concentrating ability to prolonged anuria. Many cellular events contribute to renal cell injury, including cellular ATP depletion, cellular and mitochondrial calcium overload, and activation of phospholipases and oxygen radical formation. Recent clinical and experimental studies suggest that ATP-MgCl2, free radical scavengers, diuretics, vasodilators, and calcium channel blockers appear to be beneficial in preventing acute tubular necrosis after anoxic or severe hypoxic insults. Thus these agents may be helpful in altering the course of acute renal failure in shock patients and may decrease their morbidity and mortality.
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PMID:Renal response to shock. 377 12

Snake venom poisoning accounted for 1.4% of 4360 infants and children admitted to a south Indian hospital during the years 1976-1979 and was the commonest cause of acute renal failure encountered. Most of the 42 children with anuria following snake bite had evidence of intravascular coagulation and acute tubular necrosis. Russell's viper was the only snake recognized in all the cases of anuria in which species identification was possible. Renal failure complicating snake bite was relatively more frequent and more severe in children than in adults.
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PMID:Acute renal failure in children following snake bite. 618 55

The enhancement of cortex medulla and arteria iliaca can be visualized separately, evaluated densitometrically and represented graphically by means of sequential computerized tomography of the renal transplant following intravenous contrast medium bolus injection. Since this enhancement performance is mainly dependent on perfusion, it is possible to determine the perfusion value of individual measurement areas. For example, a cortical defective perfusion, as is known in rejection, becomes evident as a flattening-out of the initial rise of cortex enhancement and can be distinguished from the largely normal type of curve obtained in acute tubular necrosis (ATN). The angiographically known prolonged "wash-out time' in rejection corresponds to a long-lasting corticomedullary density gradient. Despite restricted informative value because of the relatively small number of patients, it appears that sequential computerized tomography enables differentiation of postoperative anuria.
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PMID:[Functional control of the renal transplant via sequential computerized tomography. First results (author's transl)]. 621 3

Radionuclide renal studies are particularly well suited to pediatrics as renal problems in children usually are part of a dynamic process which requires serial assessment. The absence of side-effects and the low radiation dose has added to their popularity in pediatrics. A number of different renal parameters can be evaluated using the appropriate radiopharmaceutical and method of analysis. The renal study is of value to assess patients with hydronephrosis both pre-operatively and for serial follow-up post-operatively, as well as to distinguish obstructive from non-obstructive uropathy. Perfusion to the kidney may be assessed and ischemic areas detected in children with hypertension or trauma. The renal scan commonly is used in patients with congenital anomalies such as ectopic and duplex kidneys, nonvisualized kidney on IVP and in children with oliguria or anuria secondary to diseases such as acute tubular necrosis, hemolytic uremic syndrome, and renal vein thrombosis. It frequently is done as an emergency procedure in neonates. In conjunction with the IVP and ultrasound, the renal study is useful in some cases of abdominal mass to distinguish between hydronephrosis, cystic kidneys and tumors.
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PMID:Special considerations in the pediatric use of radionuclides for kidney studies. 676 Apr

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 diagnostic work-up of the urologic patient must be tailored to the presenting symptom complex, carefully selecting from the many modilities available, those most likely to establish the diagnosis and extent of the suspected lesions. Intravenous urography is the most rewarding initial procedure for many presenting symptoms, including suspected masses, pyuria, hematuria, and flank pain. Nuclear imaging is particularly effective in differentiating renal lobulations from true masses, in demonstrating parenchymal scarring in chronic pyelonephritis when the IVP is equivocal, and in assessing the decrease in perfusion and function in obstructive nephropathy when the IVP is indeterminate. It is the preferred procedure for acute renal infarction and acute tubular necrosis and has a greater sensitivity of detection for renal trauma than the IVP. Gallium-67 renal imaging appear helpful in the detection of occult pyelonephritis or interstitial nephritis. However, it cannot differentiate focal acute pyelonephritis from abscess or abscess from neoplasm. Ultrasoneography is the initial procedure of choice in the differentiation of cystic from solid renal masses and in anuria or oliguria. When a kidney fails to visualize by IVP or nuclear imaging, it can confirm or rule out obstruction. In upper tract infections, it may demonstrate renal or perirenal abscess. Although retrograde pyelography is performed less frequently in recent years, it remains extremely useful in confirming and relieving obstructive uropathy and in delineating tumors of the collecting system. Computed tomography effectively demonstrates hydronephrosis, renal abscess, tumors, and cysts and retroperitoneal involvement. More experience is needed to judge the efficiency of "dynamic" CT for the quantification of renal function. Renal angiography remains invaluable as a secondary procedure (as opposed to initial screening) in renal trauma, vascular anomalies, and in renal tumors to delineate the anatomy of the arterial supply and possible renal vein involvement.
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PMID:Medical imaging of renal diseases-suggested indication for different modalities. 724 59

Fifty two children (upto 12 years age) with acute renal failure (ARF) admitted to the Nephrology services between January, 1989 to August, 1992 were studied to determine the cause and outcome. Of these, 39 were boys and 13 girls; 27 (51.9%) patients were below 4 years of age. Hemolytic uremic syndrome (HUS) was the commonest cause of ARF (30.8%) followed by acute tubular necrosis (ATN) in 28.84% and acute glomerulonephritis in 19.23%. All patients had severe renal involvement with anuria in 53.6% and oliguria in 46.4% at presentation. HUS was the leading cause of anuria (53.6%), followed by obstructive uropathy (21.4%). Thirty five patients required dialytic support for a median duration of 18 days (2-90 days). The mortality was 34.6%. Seven patients of HUS, 4 patients of ARF following surgery, 3 patients each of ATN and glomerulonephritis and one patient of obstructive uropathy died. Anuria at onset, central nervous system or respiratory complications and delay in institution of dialytic support were bad prognostic factors. We conclude that early referral and prompt institution of dialytic support may be helpful in decreasing the mortality.
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PMID:Pattern of acute renal failure at a referral hospital. 788 59

Three children treated for appendicitis developed anuria and acute renal insufficiency several days after appendicectomy. Associated hydronephrosis or hydroureters were present in two. At cystoscopy, marked swelling of the trigonum and ureteric orifices was seen. One patient developed unilateral acute tubular necrosis, a complication not reported before. Recognition of this rare complication of acute appendicitis, which need not be accompanied by hydronephrosis, should lead to prompt decompression by the introduction of ureteric stents.
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PMID:A rare complication of acute appendicitis: complete bilateral distal ureteral obstruction. 798 Jul 94

Graft dysfunction is a common occurrence during the first weeks following renal transplantation. The current study was designed to evaluate the potential of renal magnetic resonance (MR) perfusion imaging to differentiate acute allograft rejection (AAR) from acute tubular necrosis (ATN) during the post-transplant period. Twenty-three consecutive patients with clinically suspected ATN and/or AAR and eight consecutive control patients (asymptomatic, serum creatinine concentration < 1.5 mg/dL) underwent MR perfusion imaging of the renal allograft within 64 days after transplantation. Histopathology was obtained in all cases with clinical suspicion of ATN or AAR. Sixty sequential fast gradient-recalled-echo MR images were acquired in each patient after intravenous administration of gadolinium-DTPA (0.1 mmol/kg). Histopathology revealed 6 patients with pure AAR, 4 patients with a combination of AAR and ATN, 12 patients with ATN and 1 patient with normal findings. Kidney graft recipients with normal renal function showed a moderate increase in signal intensity (SI) of the renal cortex and medulla after administration of contrast agent followed by an immediate and short decrease in SI of the medulla (biphasic medullary enhancement pattern). The increase in cortical SI of patients with AAR was significantly smaller (61 +/- 4% increase above baseline) than that measured in normal allografts (136 +/- 9% increase above baseline) (p < 0.05) and patients with ATN (129 +/- 3% increase above baseline) (p < .05). Patients with ATN had a slightly delayed and diminished cortical enhancement and an uniphasic and lesser medullary enhancement pattern compared to that observed in normal allografts (p < 0.05). A close correlation (r = 0.72) was found between serum creatinine concentration levels and changes in SI. Thus, MR imaging results and histopathology were in agreement in 22 of 23 patients (96%). MR perfusion imaging of renal allografts can be used to noninvasively differentiate ATN from AAR during the post-transplant period, and may also be helpful in cases were covert AAR is superimposing ATN during a phase of anuria. Patients with ATN can be separated from normals in the majority of cases as reflected by an uniphasic medullary enhancement pattern.
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PMID:Functional magnetic resonance imaging of human renal allografts during the post-transplant period: preliminary observations. 930 3


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