Development of kidney scars after acute uncomplicated pyelonephritis: relationship with clinical, laboratory and imaging data at diagnosis

Follow-up of acute pyelonephritis: what causes the diffusion-weighted magnetic resonance imaging recovery to lag clinical recovery?

PURPOSE

To analyze with diffusion-weighted magnetic resonance imaging (DW-MRI) the evolution and progress to resolution of acute pyelonephritis (APN) foci over a period of 3 months after onset.

METHODS

30 women (age 22-51 years) with clinical, laboratory (white blood cell and C-reactive protein), and DW-MRI (4b-values 0, 50, 600, 1000 s/mm²) diagnosis of APN were prospectively enrolled. Two double-blinded radiologists evaluated the number of APN foci, and for each of them dimension (D), absolute diffusion coefficient (ADC), and its ratio R to the ADC of unaffected parenchyma. Signature of radiological recovery was focus no longer visible (DW-) and ADC of its site not inferior to the ADC of the unaffected parenchyma, i.e., R ≥ 0.9. Clinical and DW-MRI follow-ups (FU) were performed at 1 and 3 months.

RESULTS

At the acute stage (t ₀), 187 APN foci were found, with ADC₀ = 1.3 ± 0.2 × 10^-3 mm²/s, R ₀ = 0.65 ± 0.12, and D ₀ = 14 ± 7.5 mm. By the 1-month FU (t ₁), all patients had no symptoms and physiological laboratory values; despite this, only 80 (43%) foci were solved, increasing to 138 (74%) by at the 3-month FU. The ROC curve (AUC ≥ 0.80) identified R ₀ ≤ 0.6 and D ₀ > 15 mm as forecast of slow radiologic resolution. About 80% of foci unsolved at 1 month but with R ₁ ≥ 0.8 and D ₁ ≤ 10 mm reached solution at 3 months.

CONCLUSIONS

DW-MRI recovery of APN foci does not always coincide with clinical recovery. The evolution of an APN focus is shaped by its initial values R ₀ and D ₀. About half of the foci still visible at 1 month reached radiological resolution in the two following months.

Clinical utility of FDG PET/CT in acute complicated pyelonephritis-results from an observational study

BACKGROUND

Acute complicated pyelonephritis (ACP) is an upper urinary tract infection associated with coexisting urinary tract abnormalities or medical conditions that could predispose to serious outcomes or treatment failures. Although CT and magnetic resonance imaging (MRI) are frequently used in patients with ACP, the clinical value of ¹⁸F-fluorodeoxyglucose positron emission tomography and computed tomography (FDG PET/CT) has not been systematically investigated. This single-center retrospective study was designed to evaluate the potential usefulness of FDG PET/CT in patients with ACP.

METHODS

Thirty-one adult patients with ACP who underwent FDG PET/CT were examined. FDG PET/CT imaging characteristics, including tracer uptake patterns, kidney volumes, and extrarenal imaging findings, were reviewed in combination with clinical data and conventional imaging results.

RESULTS

Of the 31 patients, 19 (61%) showed focal FDG uptake. The remaining 12 study participants showed a diffuse FDG uptake pattern. After volumetric approximation, the affected kidneys were found to be significantly enlarged. Patients who showed a focal uptake pattern had a higher frequency of abscess formation requiring drainage. ACP patients showing diffuse tracer uptake patterns had a more benign clinical course. Seven patients had suspected extrarenal coinfections, and FDG PET/CT successfully confirmed the clinical suspicion in five cases. FDG PET/CT was as sensitive as CT in identifying the six patients (19%) who developed abscesses. Notably, FDG PET/CT findings caused a modification to the initial antibiotic regimen in nine patients (29%).

CONCLUSIONS

FDG PET/CT may be clinically useful in the assessment of patients with ACP who have a progressive disease course.

Acute Pyelonephritis - Correlation of Clinical Parameter with Radiological Imaging Abnormalities

INTRODUCTION

Pyelonephritis (PN) is a suppurative infection of the kidney, most commonly due to bacterial infection and may be either acute or chronic. Acute PN (APN) subdivided into uncomplicated and complicated. Severity of PN cannot be assessed by clinical or laboratorial parameters alone, radiological imaging such as Ultrasound (USG) abdomen, Computed Tomography (CT) is required to know the nature, extent and severity of disease and for planning interventions.

AIM

The aim of this study was to compare clinical and biochemical parameters with radiological findings (USG/CT) among patients diagnosed to have PN.

MATERIALS AND METHODS

The medical records of all patients admitted with PN at the Institute of Nephrourology, Bangalore from January 2016 to December 2016 were reviewed. Their clinical and biochemical parameter were compared with radiological findings. Statistical analysis was performed with Statistical Package for the Social Sciences (SPSS) Version 15.0.

RESULTS

There were 100 patients diagnosed with PN in the study period. Mean age of patient was 48.7 years and PN was common among females (62%). Classical triad of PN was present in 87% of patients. Acute kidney injury was present in 47% of patients. Diabetes (69%) was the most common comorbid condition. Positive urine culture was found in 24% of patients. USG abdomen was performed in all patients and it was suggestive of APN in 66% cases. CT abdomen was available for 74% and it revealed PN in 70%, of patients. Among these Emphysematous PN (EPN) was found in 4% and renal abscess in 3% of patients. In this study, USG findings of PN were correlated with triad of PN symptoms and those who had PN for the first time.

CONCLUSION

In this study, majority of the patients presented with clinical triad of PN-fever, flank pain and dysuria. Urine culture was positive only in few cases. USG was able to diagnose large number of PN cases except emphysematous change and renal abscess which was detected by CT. The detection of PN was better with CT when compared to USG.

A best practice position statement on pregnancy in chronic kidney disease: the Italian Study Group on Kidney and Pregnancy

Pregnancy is increasingly undertaken in patients with chronic kidney disease (CKD) and, conversely, CKD is increasingly diagnosed in pregnancy: up to 3 % of pregnancies are estimated to be complicated by CKD. The heterogeneity of CKD (accounting for stage, hypertension and proteinuria) and the rarity of several kidney diseases make risk assessment difficult and therapeutic strategies are often based upon scattered experiences and small series. In this setting, the aim of this position statement of the Kidney and Pregnancy Study Group of the Italian Society of Nephrology is to review the literature, and discuss the experience in the clinical management of CKD in pregnancy. CKD is associated with an increased risk for adverse pregnancy-related outcomes since its early stage, also in the absence of hypertension and proteinuria, thus supporting the need for a multidisciplinary follow-up in all CKD patients. CKD stage, hypertension and proteinuria are interrelated, but they are also independent risk factors for adverse pregnancy-related outcomes. Among the different kidney diseases, patients with glomerulonephritis and immunologic diseases are at higher risk of developing or increasing proteinuria and hypertension, a picture often difficult to differentiate from preeclampsia. The risk is higher in active immunologic diseases, and in those cases that are detected or flare up during pregnancy. Referral to tertiary care centres for multidisciplinary follow-up and tailored approaches are warranted. The risk of maternal death is, almost exclusively, reported in systemic lupus erythematosus and vasculitis, which share with diabetic nephropathy an increased risk for perinatal death of the babies. Conversely, patients with kidney malformation, autosomal-dominant polycystic kidney disease, stone disease, and previous upper urinary tract infections are at higher risk for urinary tract infections, in turn associated with prematurity. No risk for malformations other than those related to familiar urinary tract malformations is reported in CKD patients, with the possible exception of diabetic nephropathy. Risks of worsening of the renal function are differently reported, but are higher in advanced CKD. Strict follow-up is needed, also to identify the best balance between maternal and foetal risks. The need for further multicentre studies is underlined.

Renal tract abnormalities missed in a historical cohort of young children with UTI if the NICE and AAP imaging guidelines were applied

OBJECTIVE

In a historical cohort of children with a urinary tract infection (UTI) who had already undergone all the imaging procedures, the aim was to determine renal tract abnormalities which would have been missed had we implemented the new guidelines from the National Institute for Health and Care Excellence in the United Kingdom (NICE) or the American Academy of Pediatrics (AAP).

MATERIAL AND METHODS

After a UTI episode, forty-three children (28 females, 65%) aged between 2 months and 2 years presenting at two general hospitals with a febrile UTI before 2008 underwent all the recommended imaging studies predating the new guidelines. Hydronephrosis was defined and graded according to the Society for Fetal Urology (SFU) classification. Hydronephrosis grade II (mild pelvicalyceal dilatation), grade III (moderate dilatation), and grade IV (gross dilatation with thinning of the renal cortex), duplication, vesicoureteral reflux (VUR) grade II and above, renal scarring and reduced renal uptake (<45%) on technetium-99m-labeled dimercaptosuccinic acid (DMSA) scintigraphy were considered significant abnormalities. We calculated the proportion of abnormalities which would have been missed had the new guidelines been used instead.

RESULTS

The median of age was 7.6 months (mean 8.7, range 2-24 months), with the majority (n = 37, 86%) being under 1 year of age. Ultrasound (US) showed hydronephrosis in 14 (32%), all grade II. A voiding cystourethrogram (VCUG) was performed in all and showed VUR ≥ grade II in 16 (37%), including eight children (19%) where it was bilateral. DMSA scan showed scarring in 25 children (58%) of whom 11 (26%) had bilateral scars. Reduced differential renal uptake was present in 10 children (23%). Of the 29 children with normal US, 18 (62%) had renal scarring and nine (31%) had VUR ≥ grade II. The NICE guidelines would have missed 63% of the children with VUR ≥ grade II, including a high proportion of grades IV and V VUR, 44% of the children with renal scarring, and 20% of the children with decreased renal uptake, including some children with bilateral renal scarring and with decreased renal uptake. The AAP guidelines would have missed 56% of the children with VUR ≥ grade II, including a high proportion of grades IV and V VUR, and all children with renal scarring as well as those with decreased renal uptake.

CONCLUSION

The prevalence of renal tract abnormalities missed by the new guidelines is high. They should be used with full awareness of their limitations.

The clinical and imaging presentation of acute "non complicated" pyelonephritis: a new profile for an ancient disease

BACKGROUND

Acute pyelonephritis (APN) is differently defined according to imaging or clinical criteria. In adults information on the relationship between imaging and clinical data is lacking.Our study was aimed at analysing the relationship between the clinical and imaging presentation of APN, defined according to imaging criteria (parenchymal involvement at MR or CT scan).

METHODS

All consecutive patients hospitalized for "non-complicated" APN were considered (June 2005-December 2009). Clinical, biochemical and imaging data at hospitalization were analyzed by univariate and logistic regression analysis.

RESULTS

There were 119 patients, all females, median age 32 years (15-72). At hospitalization, inflammatory markers were elevated (CRP median: 12.1 mg/dL, normal < 0.8). Incomplete presentations were frequent: fever was absent in 6.7%, pain in 17.8%, lower urinary tract symptoms in 52.9%. At CT or MR scan the lesions were bilateral in 12.6%, multiple in 79.8%; abscesses were present in 39.5%. Renal scars were found in 15.1%. Positive cultures were correlated with multiple foci (multivariate OR 4.2; CI 1.139-15.515). No other sign/symptom discriminated between small lesions, abscesses or multifocal involvement.

CONCLUSIONS

APN is a protean disease. In the absence of strict correlation with clinical or biochemical markers, imaging studies are required to assess the severity of kidney involvement.

Acute Pyelonephritis and Renal Abscesses in Adults—Correlating Clinical Parameters with Radiological (Computer Tomography) Severity

Introduction: The aim of this study is to evaluate the correlations between clinical and biochemical parameters with radiological severity of CT diagnosed acute pyelonephritis (APN) and renal abscesses, thereafter defining clinical predictors to identify patients with severe APN or renal abscesses. Materials and Methods: The inpatient medical records of all patients diagnosed with APN or renal abscesses admitted over one year were reviewed. Patients with CT imaging performed were classified into 3 groups—mild APN, severe APN and renal abscesses. Clinical and biochemical parameters were correlated with radiological severity. Results: One hundred and thirty patients were included in the study. Male gender, older age, presence of diabetes mellitus and unobstructing renal stones were significantly associated with severe APN or renal abscesses. Clinical and biochemical parameters that were associated with more severe disease include a higher leucocyte count and C-reactive proteins, left neutrophil shift, thrombocytosis or thrombocytopenia, low serum albumin, acute renal impairment and bacteremia. The percentage of patients had positive urine and blood cultures were 40.8% and 30.7% respectively. Of these patients, 97.9% had severe APN or renal abscesses on CT imaging had diabetes mellitus (DM), hypotension, acute renal failure or leucocyte count of >20K. Conclusion: Our study showed a good correlation between clinical and radiological severity in adult patients with APN and renal abscesses. Patients with severe APN or renal abscesses were likely to be diabetics presenting with hypotension, acute renal impairment and a leucocyte count of greater than 20K. Key words: Computer topography (CT), Pyelonephritis, Renal abscess, Severity

'Bench' MRI before transplant on harvested kidneys: a possible tool for diagnosis of acute pyelonephritis

We present the first case in which magnetic resonance imaging (MRI) has been utilized to rule out lesions compatible with acute pyelonephritis in kidneys from a cadaveric organ donor before transplanting them. A 40-year-old female underwent diagnosis of brain death following a septic shock. The ecotomography of the kidneys showed areas compatible with micro-abscesses raising the hypothesis of acute pyelonephritis. Our radiologist proposed to perform a bench-MRI (maintaining kidneys within the sterile preservation bags constantly on ice); this did not show lesions except little cysts not relevant by the clinical point of view. We transplanted kidneys without infective complications and results were very good.

The clinical spectrum of acute 'uncomplicated' pyelonephritis from an emergency medicine perspective

Acute uncomplicated pyelonephritis (APN) is a complex clinical entity, which is defined differently based on clinical or imaging criteria. The aim of this study was to describe the clinical and radiological presentation of APN-upper urinary tract infection (UTI) cases observed between May 2005 and June 2006 and hospitalised in the Emergency Medicine ward of San Luigi Hospital, Orbassano, Turin, Italy. All patients underwent imaging scans and were differentiated on the basis of parenchymal involvement. Of around 45000 patient visits to the emergency room between May 2005 and June 2006, 23 patients were diagnosed as having uncomplicated upper UTI (all female, age 15-57 years). Renal parenchymal involvement was confirmed by imaging in 16 cases (69.6%). The imaging spectrum ranged from a small single lesion to large multiple defects; on admission, 2 cases had no pain and 2 had no fever; lower urinary tract symptoms were present in only 13 patients (7 with parenchymal involvement). All patients with parenchymal involvement had at least one sign of systemic inflammation-infection. Most patients (15) had taken antibiotics before hospitalisation; consequently, urine cultures were negative in 21 cases (14 cases with positive imaging (87.5%)). The data from patients with and without parenchymal involvement overlapped, the only difference being a higher prevalence of high CRP levels in cases with parenchymal involvement.

Primary urinary tract infection in infants: prophylaxis for uncomplicated pyelonephritis

BACKGROUND

Urinary tract infection (UTI) is one of the most common causes of unexplained fever in infants with a reported prevalence range of 5-11%. The clinical and laboratory findings were reviewed, and diagnosis and treatment for 95 infants with primary UTI were evaluated in this study.

METHODS

All patients underwent renal ultrasonography, voiding cystourethrogram and 99mTc dimercaptosuccinic acid (DMSA) scan during hospitalization before treatment, with treatment consisting of 2- or 4-week appropriated antibiotic therapy for the patients associated upper UTI, followed by a second DMSA scan 6 months after therapy.

RESULTS

In the present study the main symptom of UTI in infants was fever. High white blood cell count was not necessarily present, and urinalysis was also an imperfect diagnostic tool for discriminating UTI. In addition, colony count from urine culture and kidney ultrasonography was not efficacious in terms of predicting the occurrence of pyelonephritis. Intravenous antibiotic for 1 week followed by 3 weeks of the same oral antibiotic provided good prophylaxis for uncomplicated pyelonephritis.

CONCLUSION

Four weeks of antibiotic treatment resulted in good recovery from pyelonephritis in the present sample of infant primary UTI cases. voiding cystourethrogram, DMSA and ultrasonography scanning should be performed in primary infant UTI.