Pyelonephritic scarring in 213 patients with upper and lower urinary tract infections: long-term followup

Distribution of Renal Scars and Intrarenal Reflux in Children with a Past History of Urinary Tract Infection

The distribution of renal scars in children with vesicoureteral reflux (VUR) and a past history of urinary tract infection was studied to see whether a correlation existed between renal scarring and intrarenal reflux. In 37 children with one or more scars in one or both kidneys, scarring was significantly more frequent in the polar areas than in the lateral area. In 7 children with intrarenal reflux (IRR), the distribution of IRR was almost identical with that of renal scarring. When children with marked VUR (grade IV-V) were analyzed separately, a uniform distribution of scars was found. It was concluded that fused papillae, which normally are most frequent in the polar area, are a prerequisite for the development of IRR/renal scars.

Long-term clinical consequences of urinary tract infections during childhood: a review

Kidney scarring related to urinary tract infection in childhood has been considered the cause of serious long-term clinical consequences. This assumption is now debated, as the advent of routine antenatal ultrasound in the 1980s has shown that a consistent part of the changes previously attributed to postinfectious scarring is mainly due to congenital malformations. With the aim of determining what is presently known on the long-term clinical consequences of urinary tract infections (UTIs) in childhood, we performed a review of the literature on the relation between UTIs and blood pressure, renal function, growth and pregnancy-related complications. By searching Medline/PubMed and Embase from 1980 to 2011, we identified 20 cohorts of children from 23 papers.

CONCLUSIONS

  Renal function: there are no clear data to establish long-term consequences following UTIs during childhood. Most data seem to show that the outcome of renal function can already be delineated at first presentation or in the initial years of follow-up; only 0.4% of children with normal renal function at start presented a decrease during follow-up. Hypertension: there is a low risk, associated with renal damage. Growth and pregnancy-related complications: the few available data seem to exclude a major influence of UTIs.

Host-pathogen checkpoints and population bottlenecks in persistent and intracellular uropathogenic Escherichia coli bladder infection

Bladder infections affect millions of people yearly, and recurrent symptomatic infections (cystitis) are very common. The rapid increase in infections caused by multidrug-resistant uropathogens threatens to make recurrent cystitis an increasingly troubling public health concern. Uropathogenic Escherichia coli (UPEC) cause the vast majority of bladder infections. Upon entry into the lower urinary tract, UPEC face obstacles to colonization that constitute population bottlenecks, reducing diversity, and selecting for fit clones. A critical mucosal barrier to bladder infection is the epithelium (urothelium). UPEC bypass this barrier when they invade urothelial cells and form intracellular bacterial communities (IBCs), a process which requires type 1 pili. IBCs are transient in nature, occurring primarily during acute infection. Chronic bladder infection is common and can be either latent, in the form of the quiescent intracellular reservoir (QIR), or active, in the form of asymptomatic bacteriuria (ASB/ABU) or chronic cystitis. In mice, the fate of bladder infection, QIR, ASB, or chronic cystitis, is determined within the first 24 h of infection and constitutes a putative host-pathogen mucosal checkpoint that contributes to susceptibility to recurrent cystitis. Knowledge of these checkpoints and bottlenecks is critical for our understanding of bladder infection and efforts to devise novel therapeutic strategies.

Approach to urinary tract infections

Urinary tract infection (UTI) is the most common infection experienced by humans after respiratory and gastro-intestinal infections, and also the most common cause of both community-acquired and nosocomial infections for patients admitted to hospitals. For better management and prognosis, it is mandatory to know the possible site of infection, whether the infection is uncomplicated or complicated, re-infection or relapse, or treatment failure and its pathogenesis and risk factors. Asymptomatic bacteriuria is common in certain age groups and has different connotations. It needs to be treated and completely cured in pregnant women and preschool children. Reflux nephropathy in children could result in chronic kidney disease; otherwise, urinary tract infections do not play a major role in the pathogenesis of end-stage renal disease. Symptomatic urinary tract infections occur most commonly in women of child-bearing age. Cystitis predominates, but needs to be distinguished from acute urethral syndrome that affects both sexes and has a different management plan than UTIs. The prostatitis symptoms are much more common than bacterial prostatic infections. The treatment needs to be prolonged in bacterial prostatitis and as cure rates are not very high and relapses are common, the classification of prostatitis needs to be understood. The consensus conference convened by National Institute of Health added two more groups of patients, namely, chronic prostatitis/chronic pelvic pain syndrome and asymptomatic inflammatory prostatitis, in addition to acute and chronic bacterial prostatitis. Although white blood cells in urine signify inflammation, they do not always signify UTI. Quantitative cultures of urine provide definitive evidence of UTI. Imaging studies should be done 3-6 weeks after cure of acute infection to identify abnormalities predisposing to infection or renal damage or which may affect management. Treatment of cystitis in women should be a three-day course and if symptoms are prolonged, then a seven day course of antibiotics should be given. Selected group of patients benefits from low-dose prophylactic therapy. Upper urinary tract infection may need in-patient treatment. Treatment of acute prostatitis is 30-day therapy of appropriate antibiotics and for chronic bacterial prostatitis a low dose therapy for 6-12 months may be required. It should be noted that no attempt should be made to eradicate infection unless foreign bodies such as stones and catheters are removed and correctable urological abnormalities are taken care of. Treatment under such circumstances can result only in the emergence of resistant organisms and complicate therapy further.

Using Tc-99m DMSA renal cortex scan to detect renal damage in women with type 2 diabetes

Women with diabetes mellitus (DM) have urinary tract infection (UTI) more often than women without DM. It is unknown, however, what the prevalence and type of renal damage due to UTI is in these women. Therefore, in this study, we compared type 2 DM women with or without UTI history for the prevalence and type of renal damage by technetium-99m dimercapto-succinic acid (Tc-99m DMSA) renal scan. A total of 128 type 2 DM women with or without UTI history received Tc-99m DMSA renal scan were included in this study. The patients were separated into three groups: (1) 43 patients without UTI history, (2) 42 patients with only lower UTI (cystitis) history and (3) 43 patients with upper UTI (pyelonephritis) history. The renal scan findings were separated into three types: (A) normal, (B) inflammation and (C) scar. The 31.9% (50/128) of type 2 DM patients had renal damages. Group 1 patients had a significantly lower prevalence of renal damages including inflammation and scar as compared to Groups 2 and 3 patients. In addition, the prevalence of renal damage was significantly higher in Group 3 than in Group 2 patients. Renal scars only were visualized in Group 3 patients. However, other clinical data were not statistically different among the three group patients. Type 2 DM women with UTI history, especially if they had upper UTI have a significantly higher prevalence of renal damage than in those without UTI.

Using Tc-99m DMSA renal scan to detect renal damage in Taiwanese women with Type 2 diabetes--a preliminary report

In this preliminary study, we compared control women and Type 2 diabetes mellitus (DM) women for the prevalence and type of renal damage as revealed by technetium-99m dimercapto-succinic acid (Tc-99m DMSA) renal scan.

METHODS

A total of 20 control women and 60 women with Type 2 DM received Tc-99m DMSA renal scan were included in this study. The 60 women with Type 2 DM were separated into three groups: 20 women without UTI history, 20 patients with cystitis histories only, and 20 with pyelonephritis histories.

RESULTS

All of the control women had normal Tc-99m DMSA renal scan findings. However, 38.3% of Type 2 DM wonmen had abnormal Tc-99m DMSA renal scan findings. Type 2 DM women without UTI history had no abnormal scan findings. The prevalence of abnormal renal scan findings was significantly higher in Type 2 DM women with pyelonephritis (90.0%) than with cystitis alone (25.0%). Renal scar findings were found only in Type 2 DM women with pyelonephritis (40.0%).

CONCLUSIONS

Compared with control women, women with Type 2 DM, especially if they had UTI and pyelonephritis histories, have a significantly higher prevalence of abnormal Tc-99m DMSA renal scan findings.

Objective evidence of a high prevalence of renal damage in women with type 2 diabetes by technetium-99m DMSA renal cortex scan findings

OBJECTIVES

To compare control women with men and women with type 2 diabetes mellitus (DM) for the prevalence and type of renal damage due to urinary tract infections (UTIs) using technetium-99m dimercapto-succinic acid (99mTc DMSA) renal scanning. Women with DM have UTIs more often than do women without DM. It is unknown, however, what the prevalence and type of renal damage due to UTI are in these women.

METHODS

Three groups of patients: 28 control women without type 2 DM and a history of UTIs, 25 male patients with type 2 DM but without a history of UTIs, and 103 female patients with type 2 DM underwent 99mTc DMSA renal scan. The 103 women with type 2 DM were separated into three groups: 36 women without a history of UTIs, 34 patients with a history of cystitis only, and 33 with a history of pyelonephritis.

RESULTS

All the control women and male patients with type 2 DM without a history of UTIs had normal 99mTc DMSA renal scan findings. However, 39.8% of women with type 2 DM had abnormal 99mTc DMSA renal scan findings. Women with type 2 DM without a history of UTI had a significantly lower prevalence of abnormal renal scan findings than did those with a history of cystitis only or pyelonephritis. In addition, the prevalence of abnormal renal scan findings was significantly higher in women with type 2 DM with pyelonephritis than in those with a history of cystitis only. Renal scars on 99mTc DMSA renal scans were found in women with type 2 DM and a history of pyelonephritis.

CONCLUSIONS

Compared with control women and men with type 2 DM, women with type 2 DM, especially if they had a history of UTIs, had a significantly higher prevalence of abnormal 99mTc DMSA renal scan findings.

Prevalence of urinary tract infection and renal scars in patients with diabetes mellitus

In a case control study, we assessed the prevalence of bacterial urinary tract infections (UTI) and renal scarring in 155 consecutive type 1 (n=102) and type 2 (n=53) diabetic individuals and 128 healthy controls. Subjects who received antibiotics during the past 6 months, pregnant women and those with overt renal failure were excluded. In all subjects, urine culture and 99m Technetium (Tc) dimercapto-succinic acid renal scan was performed. UTI was diagnosed if two consecutive urine cultures grew the same organism with at least 10(5) colony forming unit (cfu)/ml in asymptomatic and at least 10(4) cfu/ml in symptomatic subjects, respectively. Renal scan was considered abnormal if focal or multiple tracer uptake defects and/or break in cortical outline were observed. The prevalence of UTI in diabetes mellitus was higher, when compared to that in controls (9% vs. 0.78%, P=0.005). Escherichia coli was the most commonly grown organism (64.3%), followed by Staphyloccocus aureus (21.4%) and Klebsiella pneumoniae (14.3%). Prevalence of renal scarring was higher in patients with diabetes (28/155, 18.0%), when compared to that of controls (7/128, 5.4%, P=0.002). Fifty percent of patients with diabetes and UTI had renal scarring. The prevalence in diabetics with no UTI was also higher, when compared to controls (14.8 vs. 5.5%, P<0.01). The prevalence of UTI as well as renal scarring was significantly higher in females, when compared to male diabetics. No significant difference in vascular events, hypertension, proteinuria, renal function tests and HbA1 was observed in patients with and without renal scar. Thus, patients with diabetes mellitus have 10- and 3-folds increased risk of UTI and renal scarring, respectively. The results could help prioritize protocols for management of UTI among patients with diabetes mellitus.

Antibacterial prophylaxis in children with urinary tract infection

The aim, in conservative management of vesico-ureteric reflux by antimicrobial prophylaxis, is to prevent recurrent febrile urinary tract infections and consequent renal scarring. However, the effects of this prophylactic strategy are difficult to evaluate, since the required studies comparing children on prophylaxis with controls (without prophylaxis but under careful supervision) are lacking. Furthermore, the optimal length of prophylaxis needs to be defined. Since risk of renal scarring is believed to occur more frequently in young people, and since recurrent urinary infections mainly affect girls, the age and sex of subjects are important in the design of a prophylactic regimen. Nitrofurantoin and trimethoprim are the most common agents used for long-term, low-dose antibacterial prophylaxis. Break-through infections still result from non-compliance and from development of bacterial resistance, the latter mainly arising with trimethoprim. Few studies of prophylactic drugs are available that adequately define patient materials and include a random allocation to the different agents. Further studies of the effects of alternative prophylactic agents are called for, preferably combined with fresh insight into the ecological impact on the bowel and periurethral floras.

Demonstration of a "renogastric reflex" after rapid distension of renal pelvis and ureter in nonanesthetized patients

OBJECTIVES

Renal or ureteral diseases are often associated with nausea, vomiting, and abdominal pain. The aim of the current study was to investigate the cause of gastric manifestations that accompany renoureteral disorders.

METHODS

A 3F balloon-tipped catheter was introduced by means of a flexible cystoscope into the renal pelvis of 14 healthy volunteers (mean age 38.6 years; 10 men, 4 women), and the effect of rapid and slow renal pelvic and ureteral distension on the pyloric sphincter, gastric corpus, lower esophageal sphincter, and esophagus was recorded. The renal pelvis and ureter were then anesthetized and the tests repeated.

RESULTS

Rapid renal pelvic distension effected a significant rise in pressure in the renal pelvis at the 6-mL distension and above and in the pyloric sphincter at 10 and 1 2 mL. Loin and epigastric pain as well as nausea in all subjects and vomiting in 5 occurred at the 10 and 1 2-mL distensions. Slow renal pelvic distension caused a renal pelvic pressure rise at the 8-mL distension and above but no pressure changes in the pyloric sphincter or gastric corpus; loin pain, but not nausea or vomiting, occurred. Rapid ureteral distension at 1 mL was associated with loin and epigastric pain in all subjects and vomiting in 3. No epigastric pain, nausea, or vomiting occurred with slow ureteral distension. Renal pelvic or ureteral distension, slow or rapid, caused no pressure changes in the lower esophageal sphincter or esophagus. Distension of the anesthetized renal pelvis or ureter effected no gastric or esophageal pressure changes and no nausea or vomiting.

CONCLUSIONS

The study demonstrated the possible existence of a reflex relationship between the distension of the renal pelvis and ureter and the pressure of the pyloric sphincter. This reflex effect was reproducible and did not occur when the anesthetized renal pelvis or ureter was distended. We call this reflex relationship the "renogastric reflex" and suggest that it explains the cause of gastric manifestations that might occur with renoureteral disorders.

Congenital reflux nephropathy and severe unilateral fetal reflux

PURPOSE

When prenatal ultrasound reveals urinary tract dilatation, fetal reflux is suspected. Postnatal voiding cystourethrography confirms the diagnosis. The origin of reflux nephropathy is controversial, and the roles of urinary tract infection and pressure effects of sterile reflux on the developing kidneys are debatable. We evaluate the relationship between sterile reflux and renal scarring.

MATERIALS AND METHODS

We reviewed the records of 100 infants and children seen during a 15-year period in whom fetal reflux had been diagnosed, including 81 with bilateral and 19 with unilateral vesicoureteral reflux. In 12 of the 19 patients voiding cystourethrography revealed unilateral grade IV or V reflux, and they comprise the study group. Split renal function was measured in all 12 patients by radionuclide renal scan shortly after birth and before urinary tract infection developed.

RESULTS

Individual renal function was 0 to 40% in all refluxing renal units. Split renal function was less than 10% in 3 kidneys, 10 to 30% in 5 and 30 to 40% in 4. There were 2 nonfunctioning kidneys. In the remaining 10 kidneys isotope distribution on the nuclear scan indicated decreased renal length and mass. Subsequently 7 patients had breakthrough urinary tract infections while on antibiotic chemoprophylaxis. Nephrectomy, and nephroureterectomy and ureteral reimplantation with or without tapering were performed in 3 and 9 refluxing ureters, respectively. Pathological examination of the 3 nephrectomy specimens revealed severe renal dysplasia consisting of persistent primitive ducts and nests of metaplastic cartilage.

CONCLUSIONS

Our study supports the notion that renal impairment associated with severe fetal reflux is present at birth, and it is likely due to congenital dysplasia.

Reflux nephropathy and pregnancy

Reflux nephropathy is one of the renal diseases encountered most frequently in women of childbearing age. Patients with severe bilateral atrophy are the most likely to develop proteinuria, hypertension, focal glomerular sclerosis and progressive chronic renal failure, and those with persistent vesicoureteral reflux are the most likely to suffer recurrent pyelonephritic episodes. Often the disease is clinically latent and first manifests itself in pregnancy, mainly by urinary tract infection but also by proteinuria, hypertension, pre-eclampsia or renal failure. Pregnancy is most often successful and uneventful whenever renal function is normal or near normal and hypertension is absent at conception. Urinary tract infection accounts for frequent morbidity but rarely results in fetal mortality. By contrast, when renal function is significantly impaired, that is in patients whose plasma creatinine concentration is in excess of 0.20-0.22 mmol l-1 at conception, especially when hypertension is also present, there is clearly a high risk of fetal growth retardation or intrauterine death. Moreover, there is a striking risk of rapid worsening of renal function and hypertension, with accelerated progression towards end-stage renal failure. Thus, women with reflux nephropathy should attempt to conceive before the plasma creatinine concentration has reached 0.20 mmol l-1, and patients with values higher than these should be clearly advised of the high risk for both the pregnancy and the progression of the disease.

99mTechnetium dimercaptosuccinic acid scintigraphy in the diagnosis of acute pyelonephritis in rats

The use of 99mtechnetium dimercaptosuccinic acid (99mTc-DMSA) scintigraphy for the early diagnosis of pyelonephritis has been evaluated in a study performed on adolescent female Sprague-Dawley rats exposed to an ascending Escherichia coli infection. The rats were studied with DMSA scintigraphy either before and 5 days after the infection or 5 and 28 days after the infection. One group of rats received anti-microbial treatment during days 6-11. After the last DMSA scintigraphy the rats were sacrificed and the kidneys prepared for light microscopy study. Kidney morphology was normal and DMSA uptake was high and homogeneous in all control rats. The majority of the rats exposed to E. coli developed inflammatory changes, on light microscopy which extended to various degrees in the renal parenchyma. Five days after the infection the DMSA uptake was consistently reduced, if the inflammatory lesion on light microscopy involved more than 15% of the renal cortex. Twenty-eight days after infection the inflammatory changes were less extensive than at 5 days. The DMSA uptake had usually improved. At this time, however, areas of decreased DMSA uptake could be detected even if the light microscopy changes involved less than 15% of the parenchyma. Microscopical lesions were less frequent and less extensive in the treated than in the untreated rats. The complete return to normal of previously abnormal DMSA uptake was only observed in treated rats. In a few untreated rats cortical scars had formed by day 28. The scars appeared in areas with decreased DMSA uptake at 5 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Reflux nephropathy and pregnancy

Reflux nephropathy is one of the most frequent renal diseases encountered in women of childbearing age. Patients with severe bilateral atrophy are the most likely to develop proteinuria, hypertension, focal glomerular sclerosis and progressive chronic renal failure, and those with persistent vesicoureteral reflux are the most likely to suffer recurrent pyelonephritic episodes. Often the disease is clinically latent and first manifests itself in pregnancy, mainly by urinary tract infection but also by proteinuria, hypertension, pre-eclampsia or renal failure. Pregnancy is most often successful and uneventful whenever renal function is normal or near normal and hypertension is absent at conception. Urinary tract infection accounts for frequent morbidity but rarely results in fetal mortality. By contrast, when renal function is significantly impaired, that is in patients whose plasma creatinine concentration is in excess of 0.18-0.20 mmol/l at conception, especially when hypertension is also present, there is clearly a high risk of severe fetal growth retardation or intrauterine death. Moreover, there is a striking risk of rapid worsening of renal function and hypertension, with accelerated progression towards end-stage renal failure. Thus, women with reflux nephropathy should attempt to conceive before the plasma creatinine concentration has reached 0.18 mmol/l, and patients with values higher than these should be clearly advised of the high risk for both the pregnancy and the progression of the disease.

Reflux uropathy

Although much remains to be learned, most pediatric nephrologists and urologists are now in comfortable agreement with the following assumptions: (1) Most reflux (primary reflux) is due to a congenital anatomic abnormality of the bladder trigone. (2) In many instances this anomaly improves with growth and development of the child so that the reflux may cease spontaneously. In low-grade (I-II) reflux with undilated ureters, approximately 75 to 85 per cent will stop refluxing. In higher grades (III-V) with dilated ureters, the cessation rate is in the range of only 25-30 per cent. (3) Although radiologic grading is helpful in predicting the likelihood of spontaneous cessation, it is possible to improve that predictability by cystoscopic evaluation of the size, configuration, and position of the ureteral orifice plus the length of the submucosal tunnel. (4) Reflux in combination with bacteriuria can and does lead to renal scarring. (5) Renal scarring probably does not occur in patients with primary reflux and normal voiding pressures in the absence of bacteriuria. (6) Renal growth may proceed normally despite sterile reflux. (7) A few refluxing patients, perhaps 10 per cent, will have bacteriuria despite continuous antimicrobials, and these "breakthrough" infections may cause renal scars. (8) Other patients prove either unwilling or unable to comply with continuous medications and are also vulnerable to scars. (9) A successful antireflux operation may not change the recurrence rate of urinary tract infections per se, but it almost eliminates the likelihood of pyelonephritic episodes and the necessity for further continuous antibiotics. Unfortunately, in patients with intermediate grades of reflux, it is not presently known whether an early surgical correction might be more effective in allowing normal renal growth, in avoiding renal scars, and in preventing eventual hypertension, which is present as a late complication in almost 20 per cent of the patients. The data to answer this important question should ultimately be forthcoming from the current International Collaborative Reflux Study.

Reflux nephropathy

This article reviews current concepts of reflux nephropathy, including the pathophysiology, diagnosis, relationship to infection, role in causing end-stage renal disease, and appropriate treatment and management. The condition is defined from a epidemiologic point of view herein, and attention also is given to possible progressions this condition can take.

A modified bladder washout test to improve diagnostic results in chronic urinary tract infections

Bladder washout (BWO) and antibody-coated bacteria (ACB) tests were performed on 25 patients with radiological and/or clinical evidence of chronic upper urinary tract infection (UTI) and 12 patients with asymptomatic bacteriuria. Using a traditional single-washout procedure, the BWO test gave equivocal results in many cases of chronic pyelonephritis; this seemed mainly due to the lack of complete bladder sterilization. A modified procedure, including double sterilization and irrigation, biochemical typing of isolated bacteria, and evaluation of temporal pattern of bacteriuria recurrence, was then introduced. Although preliminary results of the modified BWO test demonstrated a general improvement in the diagnosis of the infection site, it seemed rather difficult, at least in chronic UTI, to establish localizing criteria based on definite numeric changes in bacterial counts after washout.