Machine learning constructs a diagnostic prediction model for calculous pyonephrosis.

In order to provide decision-making support for the auxiliary diagnosis and individualized treatment of calculous pyonephrosis, the study aims to analyze the clinical features of the condition, investigate its risk factors, and develop a prediction model of the condition using machine learning techniques. A retrospective analysis was conducted on the clinical data of 268 patients with calculous renal pelvic effusion who underwent ultrasonography-guided percutaneous renal puncture and drainage in our hospital during January 2018 to December 2022. The patients were included into two groups, one for pyonephrosis and the other for hydronephrosis. At a random ratio of 7:3, the research cohort was split into training and testing data sets. Single factor analysis was utilized to examine the 43 characteristics of the hydronephrosis group and the pyonephrosis group using the T test, Spearman rank correlation test and chi-square test. Disparities in the characteristic distributions between the two groups in the training and test sets were noted. The features were filtered using the minimal absolute value shrinkage and selection operator on the training set of data. Auxiliary diagnostic prediction models were established using the following five machine learning (ML) algorithms: random forest (RF), xtreme gradient boosting (XGBoost), support vector machines (SVM), gradient boosting decision trees (GBDT) and logistic regression (LR). The area under the curve (AUC) was used to compare the performance, and the best model was chosen. The decision curve was used to evaluate the clinical practicability of the models. The models with the greatest AUC in the training dataset were RF (1.000), followed by XGBoost (0.999), GBDT (0.977), and SVM (0.971). The lowest AUC was obtained by LR (0.938). With the greatest AUC in the test dataset going to GBDT (0.967), followed by LR (0.957), XGBoost (0.950), SVM (0.939) and RF (0.924). LR, GBDT and RF models had the highest accuracy were 0.873, followed by SVM, and the lowest was XGBoost. Out of the five models, the LR model had the best sensitivity and specificity is 0.923 and 0.887. The GBDT model had the highest AUC among the five models of calculous pyonephrosis developed using the ML, followed by the LR model. The LR model was considered be the best prediction model when combined with clinical operability. As it comes to diagnosing pyonephrosis, the LR model was more credible and had better prediction accuracy than common analysis approaches. Its nomogram can be used as an additional non-invasive diagnostic technique.

Pyonephrosis among Patients with Pyelonephritis Admitted in Department of Nephrology and Urology of a Tertiary Care Centre: A Descriptive Cross-sectional Study.

Introduction: Pyonephrosis is a severe complication of pyelonephritis leading to rapid progression to sepsis and loss of renal function resulting in nephrectomy. Early identification of pyonephrosis based on clinical or radiological characteristics amongst pyelonephritis is paramount. This study aimed to determine the prevalence of pyonephrosis among patients with pyelonephritis admitted to the Department of Nephrology and Urology of a tertiary care centre. Methods: This descriptive cross-sectional study was done in a tertiary care centre among patients with pyelonephritis from 1 July 2016 to 31 Jan 2021. Ethical approval was obtained from Institution Ethics Committee (Reference number: IEC/56/21). The available clinical, demographic and laboratory parameters were recorded from the hospital records in a predesigned proforma. A convenience sampling method was used. Point estimate and 95% Confidence Interval were calculated. Results: Among 550 pyelonephritis patients, the prevalence of pyonephrosis was 60 (10.9%) (8.3-13.5, 95% Confidence Interval). The mean age was 54.62±12.14 years, and 41 (68.33%) were males. The most common clinical symptom was flank pain with or without fever in 46 (76.66%) patients. Escherichia coli was the most common offending organism in 20 (33.33%). Ultrasonography showed classical echogenic debris with floaters and internal echoes in 44 (73.33%) patients. Double J stenting was successfully done in 44 (73.33%) patients. Percutaneous nephrostomy was done in the remaining 16 (26.66%) patients. Conclusions: The prevalence of pyonephrosis in pyelonephritis is similar to previous studies done in similar settings. Keywords: pyelonephritis; pyonephrosis; kidneys.

Emergency decompression for patients with ureteral stones and SIRS: a prospective randomized clinical study.

OBJECTIVE: Patients with ureteral calculi and systemic inflammatory response syndrome (SIRS) often require emergency drainage, and percutaneous nephrostomy (PCN) and retrograde ureteral stent insertion (RUSI) are the most commonly used methods. Our study aimed to identify the best choice (PCN or RUSI) for these patients and to examine the risk factors for progression to urosepsis after decompression. METHODS: A prospective, randomized clinical study was performed at our hospital from March 2017 to March 2022. Patients with ureteral stones and SIRS were enrolled and randomized to the PCN or RUSI group. Demographic information, clinical features and examination results were collected. RESULTS: Patients (n = 150) with ureteral stones and SIRS were enrolled into our study, with 78 (52%) patients in the PCN group and 72 (48%) patients in the RUSI group. Demographic information was not significantly different between the groups. The final treatment of calculi was significantly different between the two groups (p < .001). After emergency decompression, urosepsis developed in 28 patients. Patients with urosepsis had a higher procalcitonin (p = .012) and blood culture positivity rate (p < .001) and more pyogenic fluids during primary drainage (p < .001) than patients without urosepsis. CONCLUSION: PCN and RUSI were effective methods of emergency decompression in patients with ureteral stone and SIRS. Patients with pyonephrosis and a higher PCT should be carefully treated to prevent the progression to urosepsis after decompression.Key messageIn this study, we evaluate the best choice (PCN or RUSI) for patients who have ureteral stones and SIRS and to examine the risk factors for progression to urosepsis after decompression. This study found that PCN and RUSI were effective methods of emergency decompression. Pyonephrosis and higher PCT were risk factors for patients to develop to urosepsis after decompression.

[A Case of Pyonephrosis Due to Urethral Stent Forgotten for 4 Years].

A 53-year-old woman had left pyonephrosis and bladder stone. A double-J ureteral stent was placed for left ureterostenosis and she was lost to followup. Five years later, she had back pain. Computed tomography revealed left hydronephrosis, pyonephrosis and bladder stone. After drainage by percutaneous nephrostomy and antibiotic treatment, left nephroureterectomy was performed. She has been free from recurrence of infection for 3 months after the surgery.

Xanthogranulomatous Pyelonephritis with Pyonephrosis and Renal Abscess in a Young Adult: A Consequence of Neglected Urinary Tract Infection Leading to Nephrectomy.

Xanthogranulomatous pyelonephritis (XGP) is a rare form of chronic pyelonephritis, which is challenging to diagnose because its clinical presentation mimics other entities and is commonly associated with a history of urinary tract obstruction. We report a case of XGP in a young adult without nephrolithiasis and urinary tract obstruction. A 23-year-old woman presented with intermittent abdominal pain in the right upper quadrant persisting for the last ten months. The pain was dull, poorly localized, and started spreading to the right back, right shoulder, and right thigh in the last three months. Other complaints included fever, chills, pain during urination, and nausea. The patient had a history of infrequent urination, recurrent urinary tract infections (UTIs), and a low fluid intake. A physical examination revealed that the patient had right upper quadrant abdominal tenderness and right costovertebral angle tenderness. Laboratory findings showed leukocytosis and neutrophilia. The radiological examination revealed a round mass in the superior pole of the right kidney with mixed cystic and solid components, and a well-defined margin. It further enlarged from 4.5 cm to 10.6 cm in diameter in three months. The urologist performed a total right nephrectomy. The histopathological examination showed XGP with renal abscess. Proteus mirabilis was identified from the pus specimen culture. XGP should be considered in the diagnosis of patients having chronic UTI presented with or without the findings of urinary tract obstruction.

Challenges and management of laparoscopic treatment of pyonephrosis caused by calculi.

BACKGROUND: Calculous pyonephrosis is a disease characterized by infectious hydronephrosis associated with pyogenic destruction of the renal parenchyma, with complete or almost complete loss of renal function. METHODS: The clinical data of laparoscopic nephrolithotomy performed at Peking University People's Hospital from May 2017 to June 2020 were analyzed retrospectively. Eight patients (2 men; 6 women) aged 27 to 65 years (average age, 45.8 years) were included. Among them, 7 patients were treated with retroperitoneal approach and 1 patient by transperitoneal approach. All patients had received more than one endoscopic lithotripsy before nephrectomy. Renal dynamic imaging and computed tomography revealed the absence of function in pyonephrosis before nephrectomy. General clinical data and perioperative data were recorded. All nephrectomies were performed by the same physician. RESULTS: Laparoscopic surgery was successfully performed in 7 patients; however, 1 patient underwent open surgery because of bleeding. The operation time, average operation time, and blood loss were 1.5-4.5 h, 3.4 h, and 100-1000 ml (average, 300 ml), respectively. The postoperative pathology showed inflammatory renal disease in 6 patients, xanthogranulomatous pyelonephritis in 1 patient, and high-grade urothelial cancer in 1 patient. The average postoperative hospital stay was 5.3 days. One patient had a Clavien-Dindo Grade IIIb complication (severe hematuria), which required laparotomy, and was found that there was bleeding of ureteral stump. None of the patients experienced poor healing of endoscopic wounds. CONCLUSION: For patients with complicated calculous pyonephrosis, renal inflammation could not be effectively controlled, and renal function was seriously damaged. Thus, kidneys should be immediately resected. With laparoscopy, patients may recover quickly, but surgeons require enough experience when performing laparoscopy to achieve safety.

Hounsfield unit attenuation value can differentiate pyonephrosis from hydronephrosis and predict septic complications in patients with obstructive uropathy.

We aimed to assess the role of computerized tomography attenuation values (Hounsfield unit-HU) for differentiating pyonephrosis from hydronephrosis and for predicting postoperative infectious complications in patients with obstructive uropathy. We analysed data from 122 patients who underwent nephrostomy tube or ureteral catheter placement for obstructive uropathy. A radiologist drew the region of interest for quantitative measurement of the HU values in the hydronephrotic region of the affected kidney. Descriptive statistics and logistic regression models tested the predictive value of HU determination in differentiating pyonephrosis from hydronephrosis and in predicting postoperative sepsis. A HU cut-off value of 6.3 could diagnose the presence of pyonephrosis with 71.6% sensitivity and 71.5% specificity (AUC 0.76; 95%CI: 0.66-0.85). At multivariable logistic regression analysis HU ≥ 6.3 (p ≤ 0.001) was independently associated with pyonephrosis. Patients who developed sepsis had higher HU values (p ≤ 0.001) than those without sepsis. A HU cut-off value of 7.3 could diagnose the presence of sepsis with 76.5% sensitivity and 74.3% specificity (AUC 0.79; 95%CI: 0.71-0.90). At multivariable logistic regression analysis, HU ≥ 7.3 (p ≤ 0.001) was independently associated with sepsis, after accounting for clinical and laboratory parameters. Measuring HU values of the fluid of the dilated collecting system may be useful to differentiate pyonephrosis from hydronephrosis and to predict septic complications in patients with obstructive uropathy.

Minimally Invasive Percutaneous Nephrolithotomy with a Novel Vacuum-assisted Access Sheath for obstructive calculous pyonephrosis ：A Randomized Study.

PURPOSE: To investigate the safety and efficacy of Minimally Invasive Percutaneous Nephrolithotomy (MPCNL) combined with Vacuum-assisted Access Sheath in the treatment of obstructive calculous pyonephrosis. MATERIALS AND METHODS: Seventy-six patients with obstructive calculous pyonephrosis, who were planned to receive MPCNL, were randomly divided into two groups. Group A was treated with Amplatz sheath combined with Cyberwand double probe ultrasound lithotripsy, and group B was treated with Vacuum-assisted Access Sheath (VAAS, ClearPetra, Well lead Medical) combined with holmium laser lithotripsy. The primary outcome was the operation successful rate. Other perioperative, and postoperative data such as operation time, stone free rate and complications were compared between groups. RESULTS: Single 20F access sheath was established in all cases. All patients underwent one-stage procedure. Compared with group A, group B had a higher initial stone-free rate (84.2% vs 63.1%, P= .037). The operation time of group B was 56.3 ± 19.83 min, significantly shorter than that of group A at 70.4 ± 14.83 min. The complication rate of B group was 15.8%, which was lower than that of group A (P= .035 ). Five patients (15.8 %) of group B had a postoperative fever (>38.5 ºC) (Clavien grade 2) that required additional antibiotics; whereas 8 patients (21.1 %) of group A (P= .361). There was no blood transfusion in group A, and one case in group B required transfusion. CONCLUSION: One-stage MPCNL combined with Vacuum-assisted Access Sheath and holmium laser lithotripsy is a simple, safe, effective, and ergonomically practical method for selected patients with obstructive calculous pyonephrosis.

Comparative Study of Retroperitoneal Laparoscopic Versus Open Ipsilateral Nephrectomy After Percutaneous Nephrostomy: A Multicenter Analysis.

Purpose: To investigate the feasibility of retroperitoneal laparoscopic ipsilateral nephrectomy of a benign nonfunctional kidney after percutaneous nephrostomy, and to compare this method with open surgery. Materials and Methods: Data from 70 patients who underwent simple nephrectomy from January 2014 to October 2018 at three large centers were retrospectively analyzed. All patients underwent percutaneous nephrostomy because of renal or ureteral calculi with severe hydronephrosis or pyonephrosis. Simple nephrectomy was performed via retroperitoneal laparoscopic surgery (retroperitoneal laparoscopic group; n = 33) or open surgery (open group; n = 37). The retroperitoneal laparoscopic and open groups were compared regarding preoperative variables (age, sex, location of surgery, hypertension, diabetes, BMI, preoperative serum creatinine level, American Society of Anesthesiologists (ASA) grade, fistula duration, fistula size, number of fistulae, and urinary tract infection), and perioperative variables (operation time, intraoperative blood loss, postoperative drainage volume, catheter indwelling time, gastrointestinal function recovery time, duration of bedrest, duration of postoperative hospitalization, postoperative hemoglobin decline, perioperative transfusion, and postoperative complications). Results: The retroperitoneal laparoscopic group included more patients with hydronephrosis, while the open group included more patients with pyonephrosis. There were no significant differences between the two groups in age (P = .813), sex (P = .729), location of surgery (P = .345), hypertension (P = .271), diabetes (P = .394), BMI (P = .798), preoperative serum creatinine level (P = .826), ASA grade (P = .820), fistula duration (P = .108), fistula size (P = .958), number of fistulae (P = .925), urinary tract infection (P = .111), or operative time (P = .851). The retroperitoneal laparoscopic group had significantly lesser intraoperative blood loss (P = .007), postoperative drainage volume (P = .008), shorter catheter indwelling time (P = .002), gastrointestinal function recovery time (P < .001), duration of bedrest (P < .001), and duration of postoperative hospitalization (P < .001), and lesser postoperative hemoglobin decline (P = .035) compared with the open group. Conclusions: Retroperitoneal laparoscopic ipsilateral nephrectomy is feasible for a benign nonfunctional kidney after percutaneous nephrostomy. The surgical method should be selected based on the surgeon's experience and the specific situation of the patient.

A novel use of attenuation value (Hounsfield unit) in non-contrast CT: diagnosis of pyonephrosis in obstructed systems.

PURPOSE: To evaluate the predictive value of attenuation value (HU) in renal pelvis urine for detecting renal pelvis urine culture (RPUC) positivity in obstructed urinary systems. METHODS: The study group consisted of patients who had nephrostomy insertion performed because of obstructed system and suspicion of pyonephrosis and percutaneous nephrolithotomy (PCNL) patients who had obstructed calculi. Group 1 consisted of RPUC positive 28 patients during nephrostomy insertion or needle access in PCNL and group 2 consisted of 23 patients with negative RPUC. RPUC results and non-contrast computed tomography measurements [Hounsfield unit (HU)] were compared between group 1 and group 2. A cut-off value was determined for HU. All patients were grouped according to whether they were above or below this value. RESULTS: The median HU calculated from the renal pelvis was - 8.5 (range - 29/- 1) and 10 (range- 4/+ 17) (p < 0.001) in group 1 and group 2, respectively. The cut-off value of HU that predicted positive RPUC was 0. Sensitivity and specificity of HU when considering this cut-off value were 100% and 96%, respectively (p < 0.001). Whereas RPUC positivity was found in 96.6% (28/29) of patients with HU < 0, there were no patients with HU > 0 where RPUC positivity was detected (p < 0.001). CONCLUSION: In this cohort, we found that HU of the urine in the renal pelvis can be used to predict RPUC positivity.

Staging a great escape -Incidentally detected renal urothelial carcinoma with extensive squamous metaplasia presenting as pyonephrosis.

Incidentally, detected upper urinary tract urothelial carcinoma is a rare entity. We report the case of a 70-year-old female patient who presented with flank pain, pyuria, fever, and a unilateral nonfunctioning kidney with nephrolithiasis and pyonephrosis on pyelography. Routine imaging failed to identify a mass lesion. In an Indian setting, the clinical differential of tuberculosis was considered likely. A nephrectomy was performed in view of the poor perfusion and functional status of the right kidney. Histopathological examination of the kidney showed a tumor of urothelial origin arising at the renal pelvis displaying extensive squamous metaplasia. Such a near total metaplastic change is rare and has hitherto been undescribed in the renal pelvis. Activation of pleuripotent urothelial stem cells in the setting of chronic irritation and inflammation may be the pathogenetic process behind such an occurrence.

Pionefrosis por Lelliottia amnigena / Pyonephrosis by Lelliottia amnigena

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[A Case of Right Pyonephrosis Caused by Renal Pelvic Cancer].

A 47-year-old woman who was diagnosed with right pyelonephritis by a local physician, but failed to respond to antimicrobial chemotherapy, was referred to our hospital. Here, the diagnosis of right pyonephrosis was confirmed byabdominal computed tomography(CT). Retrograde pyelography(RP) revealed a severe stricture at the ureteropelvic junction, and it was considered difficult to advance a guidewire through the stricture. Urine cytologywas pseudo-positive ; thus, the possibilityof a malignant tumor of the urinarytract could not be ruled out. Therefore, right nephroureterectomywas performed. The final, histopathological diagnosis was urothelial carcinoma, (G2, pT3). After surgery, the signs and symptoms of the infection were rapidlyameliorated ; however, swelling of the lymph-nodes between the aorta and vena cava was observed, which was considered to be metastasis. Therefore, 4 courses of gemcitabine ＋cisplatin therapywere administered, which resulted in complete resolution of the lymph-node swelling. The patient has remained free of recurrence for 2 years after surgery.

Are there any predictors of pyonephrosis in patients with renal calculus disease?

The objective of the study is to identify factors predicting development of pyonephrosis in patients of renal calculus disease (RCD), as this knowledge is largely unknown. Patients of RCD without pyonephrosis (Group 1) or with pyonephrosis (Group 2) presenting between December 2013 and November 2015 were evaluated. All patients of RCD who had undergone either percutaneous nephrostomy (PCN) or surgical management (percutaneous nephrolithotomy/pyelolithotomy/nephrectomy) were included. Patients treated conservatively, by extracorporeal shock-wave lithotripsy and patients of bilateral RCD were excluded. Data regarding demography, co-morbidities, associated urologic disease, previous intervention, clinical presentation, urinary culture, renal function, grade of hydronephrosis, stone characteristics were collected. 501 patients were included (Group 1: 410; Group 2: 91). Mean age in years (35.02 versus 35.48), sex ratio (2.12:1 versus 2.25:1) and mean body mass index (kg/m2) (22.27 versus 22.15) were similar in both groups. Prevalence of diabetes mellitus (3.41% versus 3.29%, p = 1.000) was similar. Group 2 patients had longer duration of symptoms (5.77 versus 8.96 months, p < 0.0001), associated urological diseases such as ipsilateral PUJO and ureteric calculus (4.63% versus 12.08%, p = 0.0125), moderate/severe-grade hydronephrosis (49.75% versus 92.30%, p < 0.0001), presence of staghorn calculus (20.73% versus 62.63%, p < 0.0001), multiple calculi (48.29% versus 68.13% p = 0.0007) and nonfunctioning kidney (1.70% versus 71.42%, p < 0.0001) as predictors of pyonephrosis. In logistic multivariate analysis, additionally, past history of urological surgery (p = 0.044) was found associated with pyonephrosis. Our study identified some conditions associated with patients of pyonephrosis. To prove their role as risk factors we recommend further studies.

A Randomized Study of Minimally Invasive Percutaneous Nephrolithotomy (MPCNL) with the aid of a patented suctioning sheath in the treatment of renal calculus complicated by pyonephrosis by one surgery.

BACKGROUND: Calculus pyonephrosis is difficult to manage. The aim of this study is to explore the value of a patented suctioning sheath assisted minimally invasive percutaneous nephrolithotomy (MPCNL) in the treatment of calculus pyonephrosis. METHODS: One hundred and eighty two patients with calculus pyonephrosis were randomizely divided into observation group (n = 91) and control group (n = 91). The control group was treated with MPCNL traditionally using peel-away sheath while the observation group was treated with MPCNL using the patented suctioning sheath. RESULTS: All the patients in the observation group underwent one stage surgical treatment, 14 patients in the control group underwent first-stage surgery with the rest of the group underwent one stage surgery. The complication rate was 12.1% in the observation group, significantly lower than the rate in the control group which was 51.6%; One surgery stone clearance in the observation group was 96.7% while it was 73.6% in the control group; operative time in the observation group was (54.5 ± 14.5) min, compared to (70.2 ± 11.7) min in the control group; the bleeding amount in the observation group was (126.4 ± 47.2) ml, compared to (321.6 ± 82.5) ml in the control group; the hospitalization duration for the observation group was (6.4 ± 2.3) days, compared to (10.6 ± 3.7) days in the control group. Comparison of the above indicators, the observation group was better than the control group with significant difference (p < 0.001 each). CONCLUSIONS: Minimally invasive percutaneous nephrolithotomy with the aid of the patented suctioning sheath in the treatment of calculus pyonephrosis in one surgery is economic, practical, and warrants clinical promotion. TRIAL REGISTRATION: This study was registered with Chinese Clinical Trial Registry on May 18, 2016 (retrospective registration) with a trial registration number of ChiCTR-IOR-16008490 .

Pyelonephritis and obstructive uropathy: a case of acute kidney injury.

We present a case of a man in his late 50s with a history of metastatic prostate carcinoma requiring bilateral ureteric stenting. He was admitted with increasing confusion and lethargy. He was diagnosed with sepsis and an acute kidney injury (AKI). Clinical suspicions of an obstructive component to his AKI were not confirmed by an ultrasound scan, which showed a unilateral hydronephrosis unchanged from a scan 1 month previously. A nephrostomy was performed, and frank pus aspirated. The patient's clinical state improved steadily thereafter. Patients who are dehydrated, or who have suffered from malignant or fibrotic processes affecting the retroperitoneum, may present with urinary obstruction without a corresponding increase in urinary tract dilation. Additionally, there must be a suspicion of pyonephrosis in a symptomatic patient with known hydronephrosis. Clinicians should be aware that clinical suspicions of urinary obstruction not demonstrated on ultrasound scanning require further investigation.