Ultrasound, contrast-enhanced ultrasound and pyelonephritis: A narrative review.

Acute pyelonephritis (APN) is a bacterial infection resulting in kidney inflammation, typically arising as a complication of an ascending urinary tract infection that ascends from the bladder to the kidneys. Clinical diagnosis is generally based on clinical and laboratory findings. Recent guidelines recommend not performing diagnostic imaging unless a complicated APN is suspected or the infection affects high-risk patients such as the elderly, immunocompromised individuals, or diabetics. Contrast-enhanced ultrasound (CEUS) is a valuable tool in both the diagnosis and follow-up of APN. It aids in distinguishing small simple nephritic involvement from abscess complications and monitoring their evolution over time during antibiotic therapy. Given its lack of ionizing radiation and nephrotoxicity, CEUS is a valid diagnostic modality for approaching and monitoring pyelonephritis, improving early identification and characterization of inflammatory lesions. This review aims to summarize the main evidence on the use of ultrasound and CEUS in the diagnosis of APN and its follow-up.

[Xanthogranulomatous pyelonephritis : bear paw sign]. / L'image du mois. Pyélonéphrite xanthogranulomateuse : signe de la patte d'ours.

We present the pathognomonic image of the «bear paw sign¼ of xanthogranulomatous pyelonephritis, a rare form of chronic pyelonephritis typically occurring in association with obstructive uropathy (especially with staghorn calculi) and recurrent urinary tract infections.

Nous présentons l'image pathognomonique du «signe de la patte d'ours¼ de la pyélonéphrite xanthogranulomateuse, forme rare de pyélonéphrite chronique survenant classiquement sur un terrain associant une uropathie obstructive (en particulier sur lithiase coralliforme) et des infections urinaires à répétitions.

Infected calyceal diverticulum in pregnancy: A rare case.

A calyceal diverticulum is a transitional epithelium-lined outpouching of a renal calyx which communicates with the main collecting system through a narrow infundibulum. There are two types of calyceal diverticula: type I, the most common, communicates with the minor calyx, and type II communicates with the major calyx or renal pelvis. Calyceal diverticula are rare and mostly found incidentally; however, they can cause urinary tract infection symptoms (e.g., hematuria, pain, and fever). Diagnosing an infected calyceal diverticulum during pregnancy is particularly challenging due to overlapping symptoms and the limitations of imaging modalities that avoid ionizing radiation. Prompt diagnosis and treatment are necessary to avoid irreversible renal dysfunction and/or urological surgery. Currently, there are no established treatment guidelines for diagnosing and managing infected calyceal diverticula in pregnant patients. The rarity of this condition and the complexities introduced by pregnancy create challenges in standardizing care and determining the optimal treatment strategy, timing of interventions, and the impact on maternal and fetal outcomes. A 29-year-old primigravid woman presented emergently to the hospital at 15 weeks and 4 days gestation with concerns of severe right-sided flank pain and hematuria. Initial renal ultrasound revealed a complex, hypovascular lesion in the interpolar region of the right kidney measuring 6.9 × 6.8 × 3.7 cm, suspicious for mass versus pyelonephritis with associated phlegmon. Further characterization of the lesion by MRI revealed communication between the lesion and the mid-pole collecting system. Differential diagnoses included infected calyceal diverticulum, hydronephrosis of a duplicated system, renal abscess, and infected urinoma. Through a multidisciplinary approach, including ultrasound-guided placement of a drainage catheter at 16 weeks gestation, and tailored intravenous antibiotic therapy, the patient delivered a 3379 g male at 40 weeks and 0 days gestation. This case highlights the potential for conservative management in the absence of clear guidelines and underscores the importance of collaboration among obstetrics, urology, infectious disease, and interventional radiology teams. The implications of this case extend to increasing awareness of calyceal diverticula as a differential diagnosis in pregnant patients presenting with atypical urinary symptoms. It emphasizes the necessity of a multidisciplinary approach to ensure both maternal and fetal safety and offers valuable insights that could inform future cases, contributing to the development of more concrete guidelines for managing infected calyceal diverticula during pregnancy. Consent was obtained from the patient and IRB approval was not required for this case.

[What is confirmed in therapy of complicated urinary tract infections]. / Was ist gesichert in der Therapie der komplizierten Harnwegsinfektionen.

Urinary tract infections (UTI) rank among the most common bacterial infections worldwide. Clinical challenges include acute severe manifestations and frequently relapsing disease, both favored by urinary tract abnormalities and systemic immune defects. To judge morbidity during clinical infection, the ORENUC criteria assess clinical risk, likelihood of relapsing disease, extragenital manifestations, nephropathy, urologic and catheter-related factors. Additional diagnostic measures of severe and unusual manifestations include an extended history and specific clinical examination together with nephro-urological imaging, namely ultrasound, laboratory assessment of systemic disease, and removal or exchange of catheters and other foreign materials in the urinary tract. The current primary antibiotics recommended for uncomplicated pyelonephritis in Germany are gyrase inhibitors and cephalosporins. Microbiological diagnosis and resistance testing is central to improve efficacy and reduce side effects, especially in complex clinical situations. New antibiotic developments offer new options, especially in presence of proven antimicrobial resistance. Management of relapsing infections needs to aim at improvement of local urogenital and systemic immunological factors, which is however frequently challenging to impossible to achieve. Patient contributions including behavioral modifications and longterm or intermittent antibiotic and other drug therapy. Overall, therapeutic options are limited and new pathophysiological and antimicrobial strategies are urgently needed.

Advances in the Treatment of Urinary Tract Infection and Bacteriuria in Pregnancy.

Understanding the management of asymptomatic bacteriuria (ASB) and urinary tract infection (UTI) during pregnancy is important, given the prevalence of these conditions, associated risks to the mother and fetus /newborn, and potential requirement for antibiotic treatment. Screening for ASB with a urine culture is required during pregnancy, and a positive culture is treated for 5 to 7 days with culture-specific antibiotics. Recent research on non-antibiotic prevention and shortened duration of antibiotic treatment may offer a slightly different approach to ASB and UTI in pregnancy.

Towards a Reference Standard Definition of Urinary Tract Infection for Research.

Urinary tract infection (UTI) is among the most common human bacterial infections. In the context of increasing antibiotic resistance, there are many research efforts to improve the pathophysiological understanding, diagnosis, and treatment of UTI. Despite the high clinical relevance of UTI, there is high variability in definitions in the literature, making interpretation and comparison of research studies difficult, and even impossible in some cases. A recent Delphi consensus study generated a new reference standard definition for UTI that incorporates symptoms, pyuria, and urine culture results. This definition allows for designation of systemic involvement, and no longer categorizes UTIs as complicated or uncomplicated. The definition aligns with guidance from regulatory bodies for approval of UTI drugs. Implementation of a reference standard definition in the design and reporting of future investigations will allow better research design and interpretability within and outside the urology field. The new reference standard resolves some issues and offers a suitable way to unify methodology, and hence increase the potential strength of research in this area. There are some limitations and challenges for implementation, such as difficulties in establishing sensitivity and specificity values for the various settings in which the definition will be used. The inclusion of "probable" and "possible" UTI categories could be a problem in studies that require dichotomous outcomes. Nonetheless, the reference standard should be recommended until new developments become available, notably a more specific UTI biomarker than pyuria. Approaches to standardized diagnosis of catheter-associated UTIs remain unresolved. PATIENT SUMMARY: A new research definition for urinary tract infection (UTI) has been developed. Use of a single standardized definition in research will help in better design of research studies and comparison of results. Although the new definition will help in reducing the variability in UTI research reports, it has some limitations and there may be challenges to overcome before it is widely used.

Case report: Xanthogranulomatous pyelonephritis successfully treated with antibiotics.

Xanthogranulomatous inflammation (XGI) is an uncommon benign inflammatory disease process characterized by aggregation of lipid laden foamy macrophages, among other inflammatory cells. XGI affecting the kidney and renal pelvis is otherwise known as xanthogranulomatous pyelonephritis (XGP), which has been reported to be present in approximately 5% of all reported xanthogranulomatous cases. The clinical relevance of this disease is that it often mimics malignancy, and preoperative imaging is unable to differentiate between the two. Our case report demonstrated a renal lesion that mimicked malignancy and ultimately required histopathological examination for the diagnosis of XGP. Current consensus remains that surgery is the mainstay form of treatment. However, this case report showed that use of antibiotics alone can be successful as the patient showed significant improvement and resolution on interval imaging.

Plasma and Urinary Neutrophil Gelatinase-Associated Lipocalin as Predictors of Renal Parenchymal Involvement in Children with Febrile Urinary Tract Infection: A Pilot Study.

BACKGROUND: Urinary tract infections (UTIs) are very common bacterial infections in children. Early detection of renal parenchymal involvement in this setting can help clinicians make more effective treatment choices. The aim of this pilot study was to assess the ability of plasma and urinary neutrophil gelatinase-associated lipocalin (pNGAL and uNGAL) levels, measured using an automated system, to accurately predict renal parenchymal involvement in children with febrile UTIs. METHODS: This prospective single-center study included 28 children aged ≥ 4 years with a first episode of febrile UTIs. All patients underwent magnetic resonance imaging. pNGAL, uNGAL, procalcitonin, C-reactive protein (CRP), and white blood cells were measured before antibiotic therapy. RESULTS: The receiver operating characteristic (ROC) area under the curve for predicting acute pyelonephritis was 0.6 for pNGAL, 0.8 for CRP, 0.4 for PCT, and 0.4 for uNGAL. The ROC analyses showed an optimal cutoff of 141.0 ng/mL for pNGAL (sensitivity, 54.2%; specificity, 75.0%; positive predictive value, 92.9%; and negative predictive value, 21.4%). CONCLUSION: pNGAL and uNGAL did not effectively aid the early prediction of renal parenchymal involvement in children ≥ 4 years with febrile UTIs. The novelties of this study were the use of MRI as the gold standard and an automated biochemical method to measure NGAL.

Analysing the influence of dapagliflozin on urinary tract infection vulnerability and kidney injury in mice infected with uropathogenic Escherichia coli.

AIM: Sodium-glucose co-transporter-2 (SGLT2) inhibitors have revolutionized clinical medicine, but their association with urinary tract infection (UTI) risk remains debated. This study investigates the influence of dapagliflozin on UTI outcomes, focusing on kidney injury. MATERIALS AND METHODS: Female non-diabetic C57BL/6J and C3H/HeOuJ mice, along with diabetic db/db mice, were orally administered dapagliflozin (1 mg/kg or 10 mg/kg) for 7 days before transurethral uropathogenic Escherichia coli (UPEC) infection. Mice were killed either 24 h after UTI or after six additional days of dapagliflozin treatment. UPEC titers were enumerated, and kidney histopathology, injury, fibrosis and function were assessed. RESULTS: Vehicle- and dapagliflozin-treated C57BL/6J mice exhibited similar urine and bladder UPEC titers, with minimal kidney burden 24 h after UTI. In C3H/HeOuJ mice, UPEC burden was comparable in vehicle- and 1 mg/kg dapagliflozin-treated groups both 24 h and 7 days after UTI. However, C3H/HeOuJ mice receiving 10 mg/kg dapagliflozin had increased UPEC titers in the urine, bladder and kidneys at both endpoints. Kidney injury and fibrosis markers, as well as kidney function, were similar in vehicle and dapagliflozin groups. In diabetic db/db mice receiving dapagliflozin, UPEC strain UTI89 titers were reduced 7 days after UTI compared to vehicle-treated mice, but no difference in UPEC titers was observed when mice were infected with UPEC strain CFT073. Kidney injury and fibrosis markers and kidney function remained similar across treatment groups. CONCLUSIONS: Dapagliflozin does not consistently influence UTI susceptibility and shows limited impact on kidney injury or fibrosis, suggesting SGLT2 inhibitors have minimal effects on UTI-related kidney complications.

Preoperative renal arterial embolization in high-risk nephrectomy: A case report of a 48-year-old patient with severe emphysematous pyelonephritis.

A 48-year-old female with a background history of alcoholic liver cirrhosis and noninsulin-dependent diabetes presented to our institution with emphysematous pyelonephritis of the right kidney diagnosed on CT. Both urine and blood culture grew multidrug-resistant Escherichia coli. The patient developed severe thrombocytopenia, hyponatremia, confusion as well as septic shock. Preoperative right renal arterial embolization was performed, followed by immediate primary nephrectomy. This article reports the first documented case of preoperative angioembolization to prevent severe intraoperative hemorrhage and vascular complications in severe emphysematous pyelonephritis.

Xanthogranulomatous Pyelonephritis: A pooled quantitative analysis of published cases.

Xanthogranulomatous Pyelonephritis (XGP) is a serious and rare inflammatory disease of unknown etiology. This systematic review analyzes XGP cases. We performed a literature search for "Pyelonephritis, Xanthogranulomatous." The primary composite outcome was recovery with post-surgery complications, partial recovery, death, or chronic kidney disease. The secondary outcome was any presentation or treatment complication. Predictor variables consisted of demographics, history, symptoms, and diagnosis/management. Among the 251 patients, the mean age was 36.1 years, and 57.4% were female. The most common symptom and finding were fever (55.0%) and renal stones (53.8%), respectively. There were 15.5% with the composite outcome. There were 51.0% with any presentation or treatment complication. Multivariate logistic regression analysis for the composite outcome showed that kidney of both/horseshoe (OR:3.86, 95% CI:1.01, 14.73, p = 0.048), dialysis required (OR:8.64, 95% CI:2.27, 32.94, p = 0.002), and operative treatment of nephrostomy or nephrostomy followed by nephrectomy (OR:4.57, 95% CI:1.58, 13.17, p = 0.01) were each significantly associated with increased odds. Fever (OR:3.04, 95% CI:1.63, 5.67, p <0.001) and renal stones (OR:2.55, 95% CI:1.35, 4.81, p = 0.004) were each significantly associated with increased odds for any presentation/treatment complication. In conclusion, XGP patients with involvement of both or horseshoe kidneys, dialysis requirements, or treatment of nephrostomy or nephrostomy followed by nephrectomy may require aggressive treatment to mitigate poor patient outcomes.

A case series of emphysematous pyelonephritis in COVID-positive patients.

Emphysematous pyelonephritis (EPN) is a rare infectious disease affecting the renal and perirenal tissues, wherein gas formation occurs in the renal parenchyma, perinephric tissues, or collecting systems. It can be life threatening with mortality rates upto 60%. Here, we report a case series of EPN during the COVID pandemic with COVID test-positive patients who were diagnosed based on clinical signs, symptoms, and CT scans. One patient was conservatively managed, one underwent nephrectomy, and the others were treated with percutaneous drainage and pigtailing. Despite being critically ill, all the patients recovered uneventfully. Owning to the rarity of the lesion and variations in the clinical spectrum, the diagnosis of EPN is challenging. EPN requires early diagnosis and prompt management. The interventional technique depends on the clinical status of the patient and the severity of the lesion. Although the threshold of intervention is low in normal clinical practice, in covid patients, we tried to manage patients conservatively and intervened only when unavoidable.

Fatal nephrobronchial fistula arising from xanthogranulomatous pyelonephritis: a case report.

Introduction: Nephrobronchial fistula is an exceptionally rare complication of renal infections, including the uncommon xanthogranulomatous pyelonephritis. Existing literature is limited to a few case reports, with antibiotic therapy and nephrectomy being the preferred treatments. Case: We present the case of a 63-year-old woman with a history of recurrent xanthogranulomatous pyelonephritis in her right kidney, requiring drainage through lumbotomy. She presented with a chronic dry cough and weight loss, without other noticeable symptoms. Imaging suggested a pulmonary abscess and nephrobronchial fistula. Despite antibiotic treatment and surgical intervention, her condition progressed fatally. Conclusion: Nephrobronchial fistulas are extremely complications of renal infections, often presenting with nonspecific symptoms. This case highlights their significant impact on morbidity and mortality, especially in resource-limited settings, and underscoring the urgent need for prompt diagnosis and treatment.

Emphysematous pyelonephritis diagnosed by acute changes detected via computed tomography: A case report.

This is the first case report in which computed tomography (CT) images of a patient with emphysematous pyelonephritis (EPN) capture the time course of emphysema from onset to resolution through conservative treatment. To re-evaluate EPN, including refractory urinary tract infections, CT scans after 72 h might be helpful.

Emphysematous Pyelonephritis in Cancer Patients: A Case Report With a Literature Review.

Emphysematous pyelonephritis (EPN) is a severe necrotising infection of the renal parenchyma which is rarely reported in cancer patients. We present a case of a 92-year-old man with urothelial carcinoma of the bladder who developed EPN after resection of the tumour. Septic shock developed and blood cultures grew extended-spectrum beta-lactamase (ESBL) Escherichia coli. Because of renal function decline with hematuria a non-contrast CT scan of the abdomen showed gas in the kidney and surrounding area consistent with EPN. After receiving appropriate antibiotics according to susceptibility testing, EPN was resolved based on a follow-up CT scan of the abdomen without requiring further surgical intervention. We review the literature and discuss the management of EPN in cancer patients.

Urinary tract infections in chronic kidney disease in Nephrology unit, University Hospital Center of Befelatanana, Antananarivo.

INTRODUCTION: Urinary tract infection is the leading cause of nosocomial infection worldwide. It is a factor in the progression of chronic kidney disease. AIM: To determine the epidemiological, clinical, microbiological, therapeutic and evolving profile of patients with chronic kidney disease and urinary tract infection. METHODS: This was a retrospective, descriptive study lasting 5 years, from January 2014 to december 2018 in chronic kidney disease with urinary tract infection. RESULTS: Fifty-one patients (7.15%) were retained with a mean age of 53.03 years and a sex ratio of 0.55. Chronic kidney disease was in end-stage in 45.1% (n=23). Cystitis was found in 49.02% (n=25) and gram-negative bacilli were found in 74.50% (n=38), predominantly Escherichia coli (54.90%). Third generation of cephalosporins and fluoroquinolones were frequently prescribed as probabilistic antibiotics. Resistance to beta-lactam antibiotics was 50% for Escherichia coli. Factors influencing severe infection were: advanced age, male gender, urinary lithiasis, multiple antibiotic resistance and non-enterobacterial germs. CONCLUSION: Urinary tract infection in chronic kidney disease were frequent and particularly severe.

Update of the Spanish clinical practice guideline for urinary tract infection in infants and children. Summary of recommendations for diagnosis, treatment and follow-up.

The management of urinary tract infection (UTI) in infants and children has changed significantly over the past few decades based on scientific evidence that questioned the efficacy of strategies used to prevent kidney injury and subsequent progression to chronic kidney disease, which is very unlikely in most paediatric cases. However, there is still substantial heterogeneity in its management and uncertainty regarding the diagnosis, indication of imaging tests, treatment or follow-up in these patients. The Spanish clinical practice guideline has been updated through the review of the literature published since 2009 and a rigorous evaluation of current clinical practice aspects, taking into account the evidence on the benefits of each intervention in addition to its risks and drawbacks to attempt to provide more precise recommendations.

Xanthogranulomatous pyelonephritis in a patient with polycystic kidney disease without underlying risk factors: a case report.

Xanthogranulomatous pyelonephritis (XGP) is an extremely rare, chronic granulomatous inflammatory condition thought to arise secondary to a combination of obstruction, recurrent bacterial infection and an incomplete immune response although the etiology of XGP is more complex. We would like to report a case of XGP occurring in a patient with polycystic kidney disease (PCKD), which has not been previously documented in etiology. A 29-year-old woman presented to our hospital with right upper quadrant pain for 5 days. She had experienced a low-grade fever, generalized weakness, and myalgia throughout her body for 2 weeks. She had no history of renal stones or recurrent UTIs. Contrast-enhanced CT revealed a well-enhancing large septated cystic mass in the right kidney and numerous cysts in the liver and both kidneys. Open right radical nephrectomy was performed due to the suspicion of renal cell carcinoma, as there was no response to antibiotics over 7 days. Gross specimen demonstrated architectural distortion due to xanthomatous nodules and a dilated pelvico-calyceal system filled with pus and blood. Microscopic examination revealed infiltration of neutrophils and lipid-laden macrophages. The patient is currently being followed up in the outpatient clinic without recurrence of XGP. This is the first reported case of XGP in a patient with underlying PCKD. Physicians should consider PCKD as a potential underlying cause of XGP.

Influence of Kidney Environment Parameters on Antibiotic Efficacy Against Uropathogenic Escherichia coli.

BACKGROUND AND OBJECTIVE: Urinary tract infections (UTIs) are common infections affecting the urinary system, predominantly caused by bacterial pathogens, with Escherichia coli being the most frequent pathogen. Infections of the kidney (eg, pyelonephritis) are severe and challenging to treat, due to the specific tissue microenvironment. In this study, the influence of different parameters mimicking the kidney environment on the effectiveness of antibiotics prescribed for pyelonephritis on the growth of uropathogenic strains was analyzed. METHODS: To investigate the influence of different factors mimicking the kidney environment, we tested the effect of different kidney-representative concentrations of sodium chloride and urea, and different pH values on the efficacy of ertapenem, levofloxacin, and ceftriaxone. The effectiveness was assessed by determining the minimal inhibitory concentrations (MICs) against various E. coli strains. KEY FINDINGS AND LIMITATIONS: The study revealed that pH significantly influences the MIC values of levofloxacin. Acidification of the pH led to an increase of the MIC values, while an alkaline pH had the opposite effect. The influence of sodium chloride and urea concentrations was strain and antibiotic specific. Since three different antibiotics were tested in this study, further research with additional antibiotics is warranted. CONCLUSIONS AND CLINICAL IMPLICATIONS: These results suggest that the physicochemical conditions within the kidney can substantially influence the success of antibiotic therapy for pyelonephritis. Therefore, it is crucial for clinicians to consider these factors when selecting and dosing antibiotics. Further research is needed to evaluate a broader range of antibiotics and additional environmental parameters, to develop a more comprehensive understanding of how the kidney environment affects antimicrobial activity. This knowledge will be vital in optimizing treatment strategies for pyelonephritis, ultimately improving patient outcomes. PATIENT SUMMARY: The physicochemical conditions within the kidney influence the success of antibiotic therapy for pyelonephritis. Our findings are vital in optimizing treatment strategies and will ultimately improve patient outcomes.