Diagnostic role of intravenous urography in acute and chronic renal failure

High-dose intravenous urography (IVU) was performed 62 times in 59 patients with acute (ARF) and chronic (CRF) renal failure. The major diagnostic categories were chronic glomerulonephritis, malignant hypertension, acute tubular necrosis (ATN), and acute glomerulonephritis. The cause of the renal failure, whether CRF or ARF, oliguric or nonoliguric, could not be reliably determined by either the evolving pattern or density of nephrogram, or the size of the kidneys. Although a persistent dense nephrogram favored the diagnosis of ATN, the major correlate was a decreasing density of nephrogram as the serum creatinine level increased (P < 0.005).     

肾衰竭263例临床分析

目的探讨急慢性肾衰竭的有关临床问题。方法对1997—2003年间收治的137例急性肾衰竭和126例慢性肾衰的有关临床资料进行回顾分析。结果(1)引起慢性肾衰的原发病以感染、心血管疾患、消化道大出血等肾前性因素为主;引起慢性肾衰的原发病因以高血压、糖尿病、慢性肾小球肾炎为主;(2)器官系统功能障碍是急性肾衰的主要并发症及死亡原因。结论围绕原发病因做好治疗,是降低肾衰病死率的关键。     

肾衰竭患者血清铁蛋白及甲状旁腺激素水平的变化

目的探讨血清铁蛋白(SF)及甲状旁腺激素(PTH)在急、慢性肾衰竭诊断及治疗中的临床意义。方法随机选取急性肾衰竭患者18例(A组)和慢性肾衰竭患者30例(B组),另选取30名健康体检者(对照组,C组),检测SF、PTH、血肌酐(Cr)及血尿素(BUN)水平。结果 A组SF水平明显高于B组和C组(P<0.01),B组与C组比较无统计学差异(P>0.05);B组PTH水平显著高于A组和C组(P<0.01),A组与C组比较无统计学差异(P>0.05)。结论急性肾衰竭患者的SF明显增高,慢性肾衰竭患者的SF水平无显著变化;慢性肾衰竭患者的血清PTH水平显著增高,急性肾衰竭患者的血清PTH水平无显著变化。     

Current role of color Doppler ultrasound in acute renal failure]

Acute Renal Failure (ARF) is characterized by a rapid decline of the glomerular filtration rate, due to hypotension (prerenal ARF), obstruction of the urinary tract (post-renal ARF) or renal parenchymal disease (renal ARF). The differential diagnosis among different causes of ARF is based on anamnesis, clinical symptoms and laboratory data. Usually ultrasound (US) is the only imaging examination performed in these patients, because it is safe and readily available. In patients with ARF gray scale US is usually performed to rule out obstruction since it is highly sensitive to recognize hydronephrosis. Patients with renal ARF have no specific changes in renal morphology. The size of the kidneys is usually normal or increased, with smooth margins. Detection of small kidneys suggests underlying chronic renal pathology and worse prognosis. Echogenicity and parenchymal thickness are usually normal, but in some cases there are hyperechogenic kidneys, increased parenchymal thickness and increased cortico-medullary differentiation. Evaluation of renal vasculature with pulsed Doppler US is useful in the differential diagnosis between prerenal ARF and acute tubular necrosis (ATN), and in the diagnosis of renal obstruction. Latest generation US apparatus allow color Doppler and power Doppler evaluation of renal vasculature up to the interlobular vessels. A significant, but non specific, reduction in renal perfusion is usually appreciable in the patients with ARF. There are renal pathologic conditions presenting with ARF in which color Doppler US provides more specific morphologic and functional information. In particular, color Doppler US often provides direct or indirect signs which can lead to the right diagnosis in old patients with chronic renal insufficiency complicated with ARF, in patients with acute pyelonephritis, hepatic disease, vasculitis, thrombotic microangiopathies, and in patients with acute thrombosis of the renal artery and vein. Contrast enhanced US is another useful diagnostic tool in patients with ARF which has been recently introduced in clinical practice. Microbubble administration may reduce technical failure in the evaluation of the renal artery. Moreover, perfusion defects due to stenosis or thrombosis of the renal segmentary vessels are better recognized. New diagnostic possibilities of enhanced US include evaluation of both cortical and medullar vessels, and functional evaluation of renal perfusion. Measuring the transit time of the microbubbles is useful for the diagnosis of renal artery stenosis and, in transplanted kidneys, for differential diagnosis between ATN and acute rejection.     

Acute renal failure: possible role of duplex Doppler US in distinction between acute prerenal failure and acute tubular necrosis

Ultrasonography (US) of the native kidneys is commonly requested for acute renal failure (ARF), although in most cases the examination results are negative. To detect changes in the Doppler waveform associated with ARF and determine whether Doppler US can provide significant diagnostic information not available with standard US, 91 patients with ARF were studied to determine a mean resistive index (RI) for each patient. Forty-six patients had acute tubular necrosis (ATN) with a mean RI +/- 1 standard deviation of .85 +/- .06, which was significantly higher than the mean RI of .67 +/- .09 in 30 patients with prerenal ARF (P less than .01). Fifteen patients had ARF due to non-ATN intrinsic renal disease (mean RI, .74 +/- .13). An elevated RI (greater than or equal to .75) occurred in 91% of patients with ATN versus only 20% of patients with prerenal azotemia. Patients with severe liver disease (hepatorenal syndrome) are a subset of those with prerenal ARF that accounted for most of the elevated RIs in this group. The study demonstrates that intrarenal Doppler US allows detection of changes associated with ARF far more often than standard US. More important, Doppler US may be helpful in distinguishing ATN from prerenal azotemia.     

原发性肾病综合征并发急性肾功能衰竭的病理与临床探讨

目的：探讨原发性肾病综合征（PNS）并发急性肾功能衰竭（ARF）患者的临床、病理及预后的关系。方法：对1994～2003年507例PNS中并发ARF的47例患者临床特征进行回顾性分析，其中32例进行了肾活检，并对病理改变进行分析。结果：本组PNS并发ARF发病率为9．2％，ARF治愈率为66．0％；转为慢性者为25．5％，死亡率为8．5％；病理改变以微小病变、系膜增生性肾炎、局灶节段性肾小球硬化为多见；间质重度损害组患者24h尿蛋白定量、纤维蛋白原、病程均显著高于间质相对损害较轻组，血浆白蛋白显著低于间质相对损害较轻组。结论：PNS并发ARF病理改变以微小病变、系膜增生性肾炎、局灶节段性肾小球硬化为主；微小病变、系膜增生性肾炎治愈率高；间质损害明显的患者，蛋白尿及低蛋白血症严重，血浆纤维蛋白原高，需积极治疗。     

Measurement of the apparent diffusion coefficient in diffuse renal disease by diffusion-weighted echo-planar MR imaging.

The purpose of this study was to determine the relationship between the apparent diffusion coefficient (ADC) and diffuse renal disease by diffusion-weighted echolanar magnetic resonance (MR) imaging (EPI). Thirty-four patients were examined with diffusion-weighted EPI. The average ADC values were 2.55 x 10(-3) mm2/sec for the cortex and 2.84 x 10(-3) mm2/sec for the medulla in the normal kidneys. The ADC values in both the cortex and medulla in chronic renal failure (CRF) kidneys and in acute renal failure (ARF) kidneys were significantly lower than those of the normal kidneys. In renal artery stenosis kidneys, the ADC values in the cortex were significantly lower than those of the normal and the contralateral kidneys. In the cortex, ADC values were above 1.8 x 10(-3) mm2/sec in all 32 normal kidneys, ranging from 1.6 to 2.0 x 10(-3) mm2/sec in all 8 ARF kidneys, and below 1.5 x 10(-3) mm2/sec in 14 of 15 CRF kidneys. In the medulla, there was considerable overlap in the ADC values of the normal and diseased kidneys. There was a linear correlation between ADC value and sCr level in the cortex (r = 0.75) and a weak linear correlation in the medulla (r = 0.60). Our results show that diffusion-weighted MR imaging may be useful to identify renal dysfunction.     

Clinical Factors Associated with Dense and Wedge-Shaped Nephrograms Detected 24 h After Chemoembolization

This investigation aimed to evaluate patient characteristics and procedural factors associated with abnormal nephrograms encountered on noncontrast computed axial tomography (CAT) obtained 24-h after transarterial chemoembolization (TACE) for primary and metastatic hepatic malignancies. Sixty hepatic chemoembolization procedures were performed in 29 patients who had a median age of 63 years (range 42–79). The male-to-female ratio was 16:13. Noncontrast CAT scans were obtained approximately 24 h after TACE as part of our institutional protocol and were examined for persistent renal nephrograms. These findings were compared with clinical and procedural parameters to determine whether there was any association with these factors or with the occurrence of acute renal failure (ARF). Abnormally persistent CAT nephrograms were observed 24 h after 28 of 60 (46.7%) TACE procedures, of which 14 (23.3%) were persistent, bilaterally dense, global nephrograms, and 14 (23.3%) were small, wedge-shaped, and focal nephrograms. The change in serum creatinine from baseline to 24 h was significantly greater (p = 0.031) in the global nephrogram group. The presence of cirrhosis, Child-Pugh score, procedure time, baseline renal insufficiency, and lower periprocedural mean arterial blood pressure were also statistically significantly associated with the occurrence of bilateral globally dense nephrograms. The procedure time was statistically significantly associated with the occurrence of wedge-like focally persistent nephrograms. Global, persistently dense nephrograms and wedge-shaped focally persistent nephrograms are not infrequently observed after TACE. Persistent global nephrograms can be an important clinical indicator of ARF. The wedge nephrogram may represent focal renal ischemia.     

Magnetic resonance imaging of the kidneys

A study of the magnetic resonance imaging (MRI) appearances of the kidneys in six normal volunteers and 52 patients is reported. Corticomedullary differentiation was seen with the inversion-recovery (IR 1400/400) sequence in the normal volunteers and in patients with functioning transplanted kidneys and acute tubular necrosis. Partial or total loss of corticomedullary differentiation was seen in glomerulonephritis, acute and chronic renal failure, renal artery stenosis, and transplant rejection. The T1 of the kidneys was increased in glomerulonephritis with nephrotic syndrome, but the T1 was within the normal range for renal medulla in glomerulonephritis without nephrotic syndrome, renal artery stenosis, and chronic renal failure. A large staghorn calculus was demonstrated with MRI, but small calculi were not seen. Fluid within the hydronephrosis, simple renal cysts, and polycystic kidneys displayed very low signal intensity and long T1 values. Evidence of recent hemorrhage into cysts was seen in polycystic kidneys. Tumors displayed varied appearances. Hypernephromas were shown to be hypo- or hyperintense with the renal medulla on the IR 1400/400 sequence. After intravenous injection of gadolinium-DTPA, there was marked decrease in the tumor T1.     

Absence of a persistent nephrogram in experimental acute renal failure.

Studies showing diminished cortical perfusion and reduced glomerular filtration in acute renal failure are apparently at odds with reports of a persistent nephrogram during urography in this disease. We followed the progression of nephrograms in eight dehydrated normal rats, in seven dehydrated rats treated with 12 mg/kg of mercuric chloride (nephrotoxic acute renal failure), and in nine dehydrated rats receiving 5 g/kg of IM-glycerol (myoglobinuric acute renal failure). To assess the capacity of our technique to identify a persistent, dense nephrogram, hemorrhagic hypotension (mean arterial pressure, 55-70 mm Hg) was induced in three rats. All rats showed nephrograms on magnification radiographs 1 minute following the injection of 1 cc/lb of sodium diatrizoate. Duplicate coded readings showed no prolongation of nephrograms in ARF-affected animals. Only the hypotensive rats manifested nephrograms on 2-hour radiographs. Some differing characteristics of nephrograms among the groups are explainable on the basis of differences in renal blood flow, as determined in separate experiments. Our findings would favor a preglomerular mechanism as the cause of oliguria in acute renal failure.     

Renal transplants: can acute rejection and acute tubular necrosis be differentiated with MR imaging?

Magnetic resonance (MR) imaging was used in 40 renal transplant recipients to determine whether this modality can enable distinction of acute tubular necrosis (ATN) and acute rejection by means of corticomedullary differentiation (CMD). Each patient underwent initial MR imaging after allograft renal transplantation. Twenty-nine of these 40 patients (72%) also underwent subsequent follow-up MR imaging. Seventeen studies were obtained during episodes of ATN; 12 of these studies (71%) showed poor CMD. Eleven studies were obtained during episodes of acute rejection; eight of these studies (73%) showed poor CMD. In addition, six of seven studies (86%) showing various combinations of renal disease (ATN, acute rejection, chronic rejection, and cyclosporine toxicity) also showed poor CMD. Loss of CMD is reversible after improvement of ATN and acute rejection. Because loss of CMD is a nonspecific though sensitive sign reflecting renal transplant dysfunction, MR imaging is of limited value in the differentiation of ATN from acute rejection.     

创伤后急性肾功能衰竭的临床分析

为探讨创伤后急性肾衰竭（ARF）病人的临床特点及早期肾替代治疗对预后的影响，回顾性分析71例创伤后ARF的临床特点，早晚期肾替代治疗效果，并与同期外科术后ARF病人进行了对比。结果发现，创伤后ARF占同期因创伤住院病人的1.06%，占同期ARF病人数的16.21%；ARF多元于伤后发生低血容量及横纹肌溶解症的病人，并发呼吸和神经系统功能衰竭时，更易发生ARF；其多脏器衰竭发生率为85.9%，，病死率高达70.4%；早期进行肾替代治疗可改善预后，其病死率（33.3%)明显低于晚期进行肾替代治疗者（59.2%)。说明创伤后ARF病人病情较重，预后差，肾替代治疗应早期进行。     

The rim nephrogram in renovascular compromise

The nephrogram is a sensitive indicator of renovascular compromise. An infrequently reported but characteristic nephrographic abnormality is the cortical rim nephrogram. This “rim sign” refers to a thin nephrographic rim outlining a kidney with an otherwise faint nephrogram. We report 2 patients with this nephrographic appearance due to acute renal artery insult. The rim nephrogram is a reliable sign of underperfusion of the kidney. It is dependent on collateral capsular vessels supplying the outer renal cortex. Underperfusion can be due to a primary renal artery problem or secondary to compromise of renal artery perfusion because of elevated interstitial or tubular pressure in the kidney. The sign has not been described with systemic circulatory problems.     

Comparison of magnetic resonance imaging and radionuclide imaging in the evaluation of renal transplant failure

Magnetic resonance imaging (MRI) was compared with radionuclide scintigraphy (RNS) in 16 patients with renal transplants undergoing renal failure to determine which modality could best discriminate between rejection, acute tubular necrosis (ATN), and cyclosporin nephrotoxicity (CN). Although all rejecting transplants had reduced corticomedullary differentiation (CMD) on T1-weighted MR images, four of five cases of ATN had appearances that could not be distinguished from rejection. A normal CMD suggests nonrejection, but diminished CMD is nonspecific. Tc-99m DTPA/I-131 hippuran RNS was superior to MRI in differentiating rejection from ATN. Although ATN and CN have similar RNS patterns, this distinction can usually be made based on the clinical time course. Other potential uses of MRI in the evaluation of the renal transplants are discussed.     

Magnetic resonance imaging in the diagnosis of acute renal allograft rejection and its differentiation from acute tubular necrosis. Experimental study in the dog

This study was designed to evaluate the potential utility of magnetic resonance imaging (MRI) for the diagnosis of acute renal allograft rejection and its differentiation from acute tubular necrosis (ATN). Eighteen canines were used. Five animals served as controls. ATN was induced in six animals by cross-clamping of the left renal artery for 90 minutes. In order to study acute renal allograft rejection, seven animals were subjected to exchange allograft transplantation of the left kidney. MRI was performed with a 0.35T superconductive magnet. A double spin-echo technique was used with varying TR and TE parameters. The spin echo images were analyzed for morphology, signal intensity, T1 and T2 relaxation times, and spin density. The most useful MRI criteria for the diagnosis of ATN and acute rejection were found to be the renal size, the intensity difference between cortex and medulla (corticomedullary contrast), and the T1 relaxation time of the cortex. Normal kidneys showed maximal corticomedullary contrast (19% +/-2) on images obtained with TR = 0.5 sec and TE = 28 msec. Cortical T1 relaxation time was 551 msec + /-73. In the ATN group, the kidneys were slightly swollen (P = ns) and the corticomedullary contrast (11% + /-3) was reduced by 42% (P less than .01). T1 of the cortex (689 + /-142) was increased by 25% (P less than .10). In acute rejection, significant renal enlargement was noted (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

肾替代治疗出院患者自测健康调查

目的了解慢性肾衰竭行肾替代治疗出院患者的健康状况。方法采用自测健康评定量表(SRHMS V1.0)对88名慢性肾衰竭、维持性透析、肾移植术后的出院患者进行现场问卷调查。结果肾衰组、透析组、移植组的生理健康、心理健康和自测健康均无明显差异,但移植组的社会健康与肾衰组相比差异有统计学意义(P<0.05),而透析组的身体活动功能、认知功能明显差于肾衰组(P<0.05)。结论肾替代治疗出院患者的自测健康与肾衰组差异无统计学意义,移植组的社会健康较差。     

Acute Renal Failure after Uterine Artery Embolization

Renal failure is a potential complication of any endovascular procedure using iodinated contrast, including uterine artery embolization (UAE). In this report we present a case of acute renal failure (ARF) following UAE performed as a treatment for uterine fibroids. The likely causes of ARF in this patient are explored and the possible etiologies of renal failure in patients undergoing UAE are reviewed.     

Report of the radionuclides in nephrourology committee for evaluation of transplanted kidney (review of techniques)

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.     

The nephrogram of normovolemic, renal artery hypotension.

Experimental hemorrhagic hypotension results in a prolonged nephrogram during excretory urography. We evaluated the effect of reduced renal perfusion pressure on the nephrogram in normovolemic dogs. Renal artery perfusion pressure to one kidney was reduced to 40-50 mm Hg by inflating a renal artery balloon catheter. Subsequent urograms were qualitatively assessed for nephrographic density. Plasma and urinary iodine concentrations were determined by fluorescent excitation analysis. Total renal blood flow (TRBF) and its intrarenal distribution were assessed with isotopically labeled microspheres. In the majority of dogs severe oliguria and a prolonged and increasingly dense nephrogram were produced in the kidney exposed to reduced perfusion pressure. The nephrogram of the contralateral, normotensive kidney rapidly diminished in density, associated with the excretion of a large volume of dilute urine. The total urinary iodine excreted in 60 min was significantly less than that excreted by both kidneys in control experiments. TRBF to the hypotensive kidney was significantly reduced from its control level, and the percentage of TRBF perfusing the outer cortex decreased.     

慢性肾衰病人感染并发症的防治

感染是慢性肾衰（CRF）病人常见而严重的并发症,是导致CRF病人高死亡率的主要原因。目前越来越多证据表明,适当的预防治疗可明显降低CRF病人某些感染并发症的发生率,如结核感染、金黄色葡萄球菌感染和肝炎病毒引起的肝脏病变。研究并制定防治CRF各种感染并发症的措施仍是临床肾脏病学者肩负的重要任务。