Emphysematous pyelonephritis with progression to necrotising fasciitis of the posterior cervical region and the retropharyngeal space.

A man in his 50s with diabetes presented with backache, left flank pain and fever. On evaluation, he was found to have emphysematous pyelonephritis of the left kidney with a paranephric abscess extending into the posterior abdominal wall and superiorly up to the posterior chest wall and inferiorly extending up to the posterior superior iliac spine. The management involved the initiation of broad-spectrum antibiotics and percutaneous drainage of the abscess. However, as he continued to worsen symptoms-wise, he underwent computed-enhanced CT of the abdomen and thorax. The imaging revealed the presence of a purulent collection in the left lumbar region with an extension along the posterior cervical region and the retropharyngeal space. He underwent a fasciotomy of the lumbar region. The occurrence of emphysematous pyelonephritis along with necrotising fasciitis is uncommon and requires early aggressive management with broad-spectrum antibiotics and adequate drainage. This emphasises the need for early reimaging if the patient does not settle with antibiotics or percutaneous drainage.

Multifocal emphysematous osteomyelitis, a do not miss diagnosis for the emergency radiologist: a case report with literature review.

Emphysematous osteomyelitis (EO) is an uncommon fatal condition with high morbidity and mortality. Simultaneous involvement of the axial and appendicular skeleton with multifocal disease is even rarer, with only a few cases being reported in the literature. We present a case of multifocal emphysematous osteomyelitis in a 56-year-old woman with concurrent emphysematous pyelonephritis complicated by psoas and epidural abscesses. The causative organism in our patient was Escherichia coli. Emergency radiologists should be aware of this condition and differentiate it from other benign entities that can present with intraosseous gas. Prompt diagnosis is important given the high morbidity and mortality with this condition. This case report emphasizes the specific pattern of intraosseous gas seen with EO, which can help diagnose EO with confidence.

Added value of non-contrast CT for the diagnosis of acute pyelonephritis in older patients with suspected infection with an unknown focus: a retrospective diagnostic study.

OBJECTIVES: In older patients, the diagnosis of acute pyelonephritis (APN) is challenging. The aim was to evaluate the added value of CT to history, physical examination and urinalysis for the diagnosis of APN in older patients with suspected infection with an unknown focus. DESIGN: Retrospective diagnostic study. SETTING: Department of General Medicine in an acute care hospital in Japan. PARTICIPANTS: Patients aged ≥65 years who underwent blood cultures, a urine culture, and chest and abdominal CT to detect the focus of infection were included. PRIMARY OUTCOME MEASURES: Two radiologists independently reviewed four non-contrast CT signs: perirenal fat stranding, pelvicalyceal wall thickening, enlargement of the kidney and thickening of Gerota's fascia. Findings on contrast-enhanced CT could not be evaluated due to an insufficient number of patients in whom contrast-enhanced CT was performed. An expert panel was used as the reference standard for APN. The added value of CT findings was quantified by comparing the diagnostic performance between a model based on 10 predictors available before CT and an extended model including the CT findings. RESULTS: Of 473 patients, 61 (14.8%) were diagnosed with APN. When the laterality of the CT findings was taken into account, the model fit was not improved by adding them. In the laterality-insensitive analysis, the model performance was significantly improved by adding the CT signs (likelihood-ratio test p=0.03; c-index 0.89 vs 0.91, p=0.03). However, their clinical utility was only to improve the classification of 11.5% of patients with APN. CONCLUSIONS: The added value of non-contrast CT findings to history, physical examination and urinalysis was limited for the diagnosis of APN in older patients with a suspected infection with an unknown focus.

The Problem of Occult Pyelonephritis: Acute Pyelonephritis in Patients Presenting Only with Lower Urinary Tract Symptoms.

Pyelonephritis is a prevalent diagnosis of emergency department visits. It commonly presents as flank pain and costovertebral tenderness with urinary symptoms. However, some cases occur without typical symptoms. Our study highlights the dubious presentation of pyelonephritis with lower urinary tract symptoms (LUTS) only. This study was conducted at a tertiary care hospital, where charts and files were reviewed from January 11, 2018 to February 28, 2019 for all the patients with a diagnosis of acute pyelonephritis from medical records. In our study, 521 patients were included and 492 (94%) of the participants were suffering from pyelonephritis. Approximately 22.8% of the patients showed the absence of both flank pain and costovertebral tenderness but were diagnosed with pyelonephritis based on computed tomography (CT) and magnetic resonance imaging (MRI). Moreover, 27% of the patients reported upper urinary tract symptoms only and were diagnosed by CT or MRI findings. Out of that only 24% and 16% of the patients reported flank pain and costovertebral tenderness, respectively. Insignificant associations with pyelonephritis were found for age, gender and other comorbidities. Our study showed a significant number of patients with pyelonephritis without any upper urinary tract symptoms. Patients with LUTS should be evaluated further by imaging if they belong to the high-risk population.

Isolated renal mucormycosis masquerading as emphysematous pyelonephritis.

Mucormycosis is an acute, life-threatening infection and isolated renal involvement is rare. Due to the angioinvasive nature of the disease, it is rapidly progressive and can be lethal if not managed expeditiously. In patients with underlying conditions of immunosuppression, diabetes mellitus, transplantation, COVID-19, intravenous drug and substance use and pyelonephritis, which is unable to be controlled via regular antibiotics, mucormycosis must be considered on the differential and antifungals must be empirically started. Most cases are often diagnosed on histopathology, which causes delayed treatment and resolution. We present a case of emphysematous pyelonephritis diagnosed on imaging and was later found to have mucormycosis on histopathological examination.

Role of MRI in the evaluation of acute pyelonephritis in a high-risk population with renal dysfunction: a prospective study.

AIMS: This study aims to evaluate the (a) accuracy of conventional and diffusion-weighted-imaging (DWI) sequences in the diagnosis of acute pyelonephritis and (b) minimum apparent diffusion coefficient (ADC) values for the diagnosis of acute pyelonephritis and the differentiation of renal abscesses from acute pyelonephritis. MATERIALS AND METHODS: Ultrasound, conventional MRI sequences, and DWI were used to evaluate the kidneys in 68 patients suspected to have acute pyelonephritis. Multiple similar regions of interest (ROIs) were placed over the renal parenchyma with visually identifiable diffusion restriction, over the non-diffusion-restricted renal parenchyma of affected kidneys and over the normal kidneys. Corresponding minimum ADCs were noted for analysis. Pyelonephritis was confirmed based on clinical criteria, laboratory findings, and by resolution/development of known complications of pyelonephritis. RESULT: DWI showed the highest sensitivity(100%), while DWI read with T2-weighted imaging (both being positive) showed the highest specificity(100%) for the diagnosis of acute pyelonephritis in our population with a high baseline creatinine. The minimum-ADC of the nephritic diffusion-restricted area in patients with confirmed pyelonephritis was significantly lower than the minimum-ADC in patients without pyelonephritis [(0.934 ± 0.220, mean ± SD) vs (1.804 ± 0.404) × 10-3 s/mm2] (p < 0.001). ROC cut-off of minimum-ADC for the diagnosis of acute pyelonephritis was 1.202 × 10-3 s/mm2 (area under curve 0.978). The minimum-ADC of the abscesses were significantly lower when compared to the minimum-ADC of the nephritic diffusion-restricted portion of the same kidney [(0.633 ± 0.248) vs (0.850 ± 0.191) × 10-3 s/mm2] (p < 0.001). CONCLUSION: DWI is an excellent stand-alone imaging tool that can be combined with conventional sequences for the diagnosis of APN even in patients with high serum-creatinine or other contraindications to intravenous contrast. Further, ADC values can be used to differentiate between renal abscesses and uncomplicated pyelonephritis.

A rare entity in a pediatric patient: coexistence of emphysematous cystitis and emphysematous pyelonephritis.

BACKGROUND: Emphysematous cystitis (EC) and emphysematous pyelonephritis (EPN) are rare urinary tract infections. They have a wide spectrum of clinical manifestations; ranging from asymptomatic to septic shock at presentation. In children, EC and EPN are rare complications of urinary tract infections (UTIs). Their diagnosis is based on clinical manifestations, laboratory results and characteristic radiological findings of gas within the collecting system, renal parenchyma and/or perinephric tissue. Computed tomography is the best radiological option in the diagnosis of EC and EPN. Despite the availability of various treatment modalities including medical and/or surgical treatment alternatives, these life-threatening conditions have high mortality rates reaching up to 70 percent. CASE: Urinary tract infection was detected in the examinations of an 11-year-old female patient suffering from lower abdominal pain, vomiting and dysuria for two days. Air was detected in the bladder wall on X-ray. EC was detected in the abdominal ultrasonography. Air formations in the bladder lumen and calyces of both kidneys in abdominal computed tomography confirmed the presence of EPN. CONCLUSIONS: Individualized treatment should be instituted according to the severity of EC and EPN, and the overall health condition of the patient.

[Challenging Case of Primary Renal Castleman's Disease Accompanied with Bacterial Pyelonephritis].

Castleman's disease is a rare lymphoproliferative disease, mostly found in the mediastinum. The number of Castleman's disease cases involving the kidneys is still limited. We report a case of primary renal Castleman's disease sporadically detected during a regular health check-up as pyelonephritis with ureteral stones. In addition, computed tomography showed renal pelvic and ureteral wall thickening with paraaortic lymphadenopathy. A lymph node biopsy was performed, but it did not confirm either malignancy or Castleman's disease. The patient underwent open nephroureterectomy for diagnostic and therapeutic purposes. The pathological diagnosis was renal and retroperitoneal lymph node Castleman's disease with pyelonephritis.

Altered Biodistribution on 99m Tc-Dimercaptosuccinic Acid Renal Scan.

ABSTRACT: 99m Tc-dimercaptosuccinic acid ( 99m Tc-DMSA) scans are used to evaluate renal cortical defects typically related to parenchymal scarring or pyelonephritis, and ectopic renal parenchyma. 99m Tc-DMSA binds to metalloproteins in proximal tubular cells and typically localizes to the renal cortex, with minimal excretion. Planar and SPECT images are obtained 2 to 4 hours after IV administration of 99m Tc-DMSA. Altered 99m Tc-DMSA biodistribution has been reported in various conditions, including renal injury, technical issues, infiltrative processes, and hematologic disorders. Here, we present a case of altered biodistribution, with hepatic and splenic radiotracer uptake in the setting of hepatosplenomegaly and hematologic abnormalities concerning for a systemic hematologic disorder/lymphohistiocytosis.

Incidence of renal scarring on technetium-99 m dimercaptosuccinic acid renal scintigraphy after acute pyelonephritis, acute focal bacterial nephritis, and renal abscess.

OBJECTIVE: To evaluate the association between the incidence of renal scarring on technetium-99 m dimercaptosuccinic acid (DMSA) renal scintigraphy and the severity of renal parenchymal infections, such as acute pyelonephritis (APN), acute focal bacterial nephritis (AFBN), and renal abscess, based on computed tomography (CT) diagnosis. METHODS: Sixty-one children with renal parenchymal infections were included and classified into two groups: those with (renal scarring group) and without renal scarring (non-renal scarring group) on chronic-phase DMSA renal scintigraphy. The severity of renal parenchymal infection was classified into three grades using CT: APN, AFBN, and renal abscess as grades 1, 2, and 3, respectively. The severity of renal parenchymal infection, vesicoureteral reflux (VUR) grade, and intrarenal reflux occurrence during voiding cystourethrography (VCUG) were evaluated between the renal and non-renal scarring groups. Fisher's exact test and Mann-Whitney U test were used for statistical analysis. RESULTS: Renal scars were detected in 28 (45.9%) of the 61 patients. We found that 2/9 (22.2%), 18/41 (43.9%), and 8/11 (72.7%) patients with APN (grade 1), AFBN (grade 2), and renal abscess (grade 3) had renal scarring, respectively. There was a significant difference in the grade of severity of renal parenchymal infection between the renal (median = 2 [interquartile range, 2-3]) and non-renal (median = 2 [interquartile range, 2-2]) scarring groups (p = 0.023). There was a significant difference in the grade of VUR between the renal (median = 3 [interquartile range, 0-4]) and non-renal (median = 0 [interquartile range, 0-2]) scarring groups (p = 0.004). No significant difference in intrarenal reflux occurrence was observed between the renal (present/absent: 3/25) and non-renal (present/absent: 0/29) scarring groups (p = 0.112). CONCLUSION: Our results showed that pediatric patients with renal scarring on chronic-phase DMSA renal scintigraphy tended to have a more severe renal infection.

An update on pyelonephritis: role of contrast enhancement ultrasound (CEUS).

Acute pyelonephritis (APN) is a bacterial infection causing inflammation of the kidneys. Diagnosis is usually based on clinical and laboratory findings. Imaging is required if a complication is suspected in acute pyelonephritis to assess the nature and extent of the lesions and to detect underlying causes. CT represents the current imaging modality of choice in clinical practice. CEUS is an alternative that has been proven to be equally accurate in the detection of acute pyelonephritis renal lesions. CEUS allows us to distinguish small simple nephritic involvement from abscess complications and to follow their evolution over time during antibiotic therapy. The absence of ionizing radiation and the lack of nephrotoxicity make CEUS an ideal tool in the study of pyelonephritis.

ACR Appropriateness Criteria® Acute Pyelonephritis: 2022 Update.

Acute pyelonephritis (APN) is a severe urinary tract infection (UTI) that has the potential to cause sepsis, shock, and death. In the majority of patients, uncomplicated APN is diagnosed clinically and is responsive to treatment with appropriate antibiotics. In patients who are high risk or when treatment is delayed, microabscesses may coalesce to form an acute renal abscess. High-risk patients include those with a prior history of pyelonephritis, lack of response to therapy for lower UTI or for APN, diabetes, anatomic or congenital abnormalities of the urinary system, infections by treatment-resistant organisms, nosocomial infection, urolithiasis, renal obstruction, prior renal surgery, advanced age, pregnancy, renal transplant recipients, and immunosuppressed or immunocompromised patients. Pregnant patients and patients with renal transplants on immunosuppression are at an elevated risk of severe complications. Imaging studies are often requested to aid with the diagnosis, identify precipitating factors, and differentiate lower UTI from renal parenchymal involvement, particularly in high-risk individuals. Imaging is usually not appropriate for the first-time presentation of suspected APN in an uncomplicated patient. The primary imaging modalities used in high-risk patients with suspected APN are CT, MRI, and ultrasound, although CT was usually not appropriate for initial imaging in a pregnant patient with no other complications. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Post mortem computed tomography is highly sensitive for pyelonephritis. A radiologic-pathologic correlation series.

Pyelonephritis is a potentially lethal disease occasionally encountered in the forensic setting. Post mortem computed tomography (PMCT) is an important investigative tool for the forensic pathologist. In particular, it may be used to document and screen disease prior to traditional autopsy methods. While the sensitivity and specificity of computed tomography for pyelonephritis is well studied in the antemortem clinical setting, the test characteristics of PMCT are not yet described in the forensic pathology literature. A series of all cases of fatal pyelonephritis identified at the Ontario Forensic Pathology Service, over the course of 1 year was studied. Radiologic, clinical and pathologic findings were reviewed. A fulsome autopsy, including histopathologic examination, was considered the gold standard for sensitivity and specificity calculations. A control group consisting of 16 cases without pyelonephritis (ex: opiate toxicity) in which both PMCT and histologic data were available by way of comparison. Sixteen cases of pyelonephritis were identified. Post mortem computed tomographical signs of pyelonephritis included asymmetric renal enlargement, perinephric fat stranding, and ectopic renal air. The most (57%) individually sensitive of these findings was perinephric fat stranding but sensitivity increased to 100% if any of the three signs were present. The control group analysis revealed the specificity of air asymmetry (81%), asymmetric renal enlargement (81%), and fat stranding (69%). PMCT findings may rule in a diagnosis of pyelonephritis, and should prompt the pathologist to grossly and microscopically examine the kidneys.

Venous gas caused by emphysematous pyelonephritis: a case report and review of literature.

BACKGROUND: Emphysematous pyelonephritis (EPN) is a potentially life-threatening disease caused by a gas-producing necrotizing bacterial infection that involves the renal parenchyma, collecting system, and/or perinephric tissue. EPN is often complicated by a previous diagnosis of diabetes mellitus, and venous air bubbles are an uncommon complication of it. We describe a 52-year-old woman who was admitted in coma, with a history of vomiting, and was found to have EPN with air bubbles in the uterine veins. We discuss the presentation, diagnosis, and pathogenesis of this uncommon but clinically significant event, and briefly review other case reports of venous gas or thrombosis caused by EPN. CASE PRESENTATION: We report the case of a 52-year-old woman with past history of type 2 diabetes mellitus, presenting with loss of consciousness after vomiting for half a day. Abdominal computed tomography scan revealed unilateral EPN with air bubbles in the uterine veins. The blood, pus, and urine cultures were positive for extended-spectrum beta-lactamase-producing Escherichia coli. The patient's condition improved well after conservative management comprising supportive measures, broad-spectrum antibiotics, percutaneous drainage therapy, and an open operation. CONCLUSIONS: Venous air bubbles are rare but fatal complication of EPN. Early diagnosis and treatment are critical to ensure good results.