RAD54L2 counters TOP2-DNA adducts to promote genome stability.

The catalytic cycle of topoisomerase 2 (TOP2) enzymes proceeds via a transient DNA double-strand break (DSB) intermediate termed the TOP2 cleavage complex (TOP2cc), in which the TOP2 protein is covalently bound to DNA. Anticancer agents such as etoposide operate by stabilizing TOP2ccs, ultimately generating genotoxic TOP2-DNA protein cross-links that require processing and repair. Here, we identify RAD54 like 2 (RAD54L2) as a factor promoting TOP2cc resolution. We demonstrate that RAD54L2 acts through a novel mechanism together with zinc finger protein associated with tyrosyl-DNA phosphodiesterase 2 (TDP2) and TOP2 (ZATT/ZNF451) and independent of TDP2. Our work suggests a model wherein RAD54L2 recognizes sumoylated TOP2 and, using its ATPase activity, promotes TOP2cc resolution and prevents DSB exposure. These findings suggest RAD54L2-mediated TOP2cc resolution as a potential mechanism for cancer therapy resistance and highlight RAD54L2 as an attractive candidate for drug discovery.

Understanding factors influencing primary treatment with intradetrusor onabotulinumtoxinA versus augmentation cystoplasty in patients with spina bifida.

PURPOSE: Surgical interventions in the urologic management of children with neurogenic bladder secondary to spina bifida aim to preserve upper tract function, prevent urinary tract infections, and optimize quality of life. However, since the introduction of intravesical onabotulinumtoxinA (Botox) in the management of these patients, the indications for choosing Botox over augmentation cystoplasty (AC) remain undefined. The objective of this study was to determine which factors lead patients to undergo Botox versus AC as a primary surgical treatment after failing medical management. METHODS: We retrospectively reviewed the records of pediatric patients with myelomeningocele undergoing either primary Botox or primary AC at our institution between 2013 and 2018. We recorded demographic and clinical information. We identified 10 important clinical decision-making factors: bladder trabeculation, vesicoureteral reflux, or hydronephrosis on imaging; end-filling pressure (EFP) ≥40 cm H2O, detrusor overactivity, detrusor-sphincter dyssynergia, or reduced capacity on urodynamic studies; physician-perceived bladder hostility; and patient/family desire for continence and independence. The presence of these factors was compared between patients undergoing either primary Botox or primary AC. RESULTS: We identified 14 and 50 myelomeningocele patients who underwent primary AC and primary Botox, respectively. We found no significant differences in age, sex, race, or history of reconstructive surgery (antegrade continence enema or catheterizable channel). For the 10 decision-making factors, desire for independence/continence (p = <0.001) and reduced capacity (p = 0.002) were significantly associated with AC, while trabeculation (p = 0.006), EFP ≥40 cm H2O (p = 0.029), rising slope (p = 0.019), and physician-perceived hostility (p = 0.012) were significantly more common with Botox. CONCLUSIONS: At our institution, quality of life measures prompted AC over objective urodynamic or imaging findings before attempting Botox. These findings support a shared decision-making approach when considering surgical intervention for neurogenic bladder secondary to myelomeningocele.

Revolutionizing DNA repair research and cancer therapy with CRISPR-Cas screens.

All organisms possess molecular mechanisms that govern DNA repair and associated DNA damage response (DDR) processes. Owing to their relevance to human disease, most notably cancer, these mechanisms have been studied extensively, yet new DNA repair and/or DDR factors and functional interactions between them are still being uncovered. The emergence of CRISPR technologies and CRISPR-based genetic screens has enabled genome-scale analyses of gene-gene and gene-drug interactions, thereby providing new insights into cellular processes in distinct DDR-deficiency genetic backgrounds and conditions. In this Review, we discuss the mechanistic basis of CRISPR-Cas genetic screening approaches and describe how they have contributed to our understanding of DNA repair and DDR pathways. We discuss how DNA repair pathways are regulated, and identify and characterize crosstalk between them. We also highlight the impacts of CRISPR-based studies in identifying novel strategies for cancer therapy, and in understanding, overcoming and even exploiting cancer-drug resistance, for example in the contexts of PARP inhibition, homologous recombination deficiencies and/or replication stress. Lastly, we present the DDR CRISPR screen (DDRcs) portal , in which we have collected and reanalysed data from CRISPR screen studies and provide a tool for systematically exploring them.

SOX9 maintains human foetal lung tip progenitor state by enhancing WNT and RTK signalling.

The balance between self-renewal and differentiation in human foetal lung epithelial progenitors controls the size and function of the adult organ. Moreover, progenitor cell gene regulation networks are employed by both regenerating and malignant lung cells, where modulators of their effects could potentially be of therapeutic value. Details of the molecular networks controlling human lung progenitor self-renewal remain unknown. We performed the first CRISPRi screen in primary human lung organoids to identify transcription factors controlling progenitor self-renewal. We show that SOX9 promotes proliferation of lung progenitors and inhibits precocious airway differentiation. Moreover, by identifying direct transcriptional targets using Targeted DamID, we place SOX9 at the centre of a transcriptional network, which amplifies WNT and RTK signalling to stabilise the progenitor cell state. In addition, the proof-of-principle CRISPRi screen and Targeted DamID tools establish a new workflow for using primary human organoids to elucidate detailed functional mechanisms underlying normal development and disease.

Robotic-assisted laparoscopic repair of a congenital rectourethral fistula with duplicated urethra.

OBJECTIVE: To describe our experience with robot-assisted laparoscopic transperitoneal repair of a congenital rectourethral fistula in a pediatric patient with a urethral duplication. METHODS: The patient is a 2-year-old male with a past medical history of Tetralogy of Fallot presenting with a febrile urinary tract infection (UTI). He was diagnosed with urethral duplication and a rectourethral fistula by voiding cystourethrogram (VCUG). The parents were counseled on various options and agreed to proceed with a robotic repair. RESULTS: Robotic-assisted transperitoneal rectourethral fistula repair was performed. The procedure time was 229 min with an estimated blood loss (EBL) of 15 mL. His postoperative course was unremarkable. At his 2-week follow-up, the urethral catheter was removed and the patient was voiding normally and having normal bowel movements. CONCLUSION: Congenital rectourethral fistula with urethral duplication is a rare anomaly with only a few reports in the literature. Pediatric robotic-assisted transperitoneal rectourethral fistula repair is a technically feasible approach in infants with minimal morbidity that allows for excellent visualization and avoids open repair.

Oncologic Fidelity of Minimally Invasive Surgery to Resect Neoadjuvant-Treated Wilms Tumors.

BACKGROUND: The Children's Oncology Group recommends upfront resection of Wilms tumor (WT), however, unique scenarios warrant neoadjuvant chemotherapy and delayed resection. We hypothesized that in the context of neoadjuvant chemotherapy, minimally invasive surgery (MIS) to resect WT achieves equivalent oncologic fidelity and better maintains therapy schedules. METHODS: A retrospective analysis of WT treated between 2010-2021 at a free-standing children's hospital was performed. Patient and disease specific characteristics were collected, and pre-resection tumor volumes (TV) were calculated. Impact of MIS or open resection on oncologic fidelity and time to resume chemotherapy was analyzed. RESULTS: For the study period, 62 patients were treated for 65 WT, and 14 patients (22.6%) received neoadjuvant chemotherapy to treat 17 WT (26.2%): 7 Stage I (all predisposition syndromes), 2 stage III, 7 stage IV, and 1 stage V (bilateral). MIS was utilized to resect 6 WT from 5 patients. For partial nephrectomy, pre-resection TV was 0.38 ml if MIS and 10.38 ml if open (P = .025). For radical nephrectomy, pre-resection TV was 31.58 ml if MIS and 175.00 ml if open (P = .101). No significant differences between surgical approach were detected regarding pathologic variables or survival. Epidural use was significantly greater with open procedures (P = .001). Length of stay was 2.00 days after MIS compared to 6.00 for open resection (P = .004). Time to resume chemotherapy was 7.00 days after MIS versus 27.00 for open (P = .004). CONCLUSION: After neoadjuvant chemotherapy for WT, MIS partial and radical nephrectomies achieved equivalent oncologic fidelity, reduced epidural use and post-operative stays, and better maintained adjuvant therapy timelines when compared to open resections.

Loss of Cyclin C or CDK8 provides ATR inhibitor resistance by suppressing transcription-associated replication stress.

The protein kinase ATR plays pivotal roles in DNA repair, cell cycle checkpoint engagement and DNA replication. Consequently, ATR inhibitors (ATRi) are in clinical development for the treatment of cancers, including tumours harbouring mutations in the related kinase ATM. However, it still remains unclear which functions and pathways dominate long-term ATRi efficacy, and how these vary between clinically relevant genetic backgrounds. Elucidating common and genetic-background specific mechanisms of ATRi efficacy could therefore assist in patient stratification and pre-empting drug resistance. Here, we use CRISPR-Cas9 genome-wide screening in ATM-deficient and proficient mouse embryonic stem cells to interrogate cell fitness following treatment with the ATRi, ceralasertib. We identify factors that enhance or suppress ATRi efficacy, with a subset of these requiring intact ATM signalling. Strikingly, two of the strongest resistance-gene hits in both ATM-proficient and ATM-deficient cells encode Cyclin C and CDK8: members of the CDK8 kinase module for the RNA polymerase II mediator complex. We show that Cyclin C/CDK8 loss reduces S-phase DNA:RNA hybrid formation, transcription-replication stress, and ultimately micronuclei formation induced by ATRi. Overall, our work identifies novel biomarkers of ATRi efficacy in ATM-proficient and ATM-deficient cells, and highlights transcription-associated replication stress as a predominant driver of ATRi-induced cell death.

Total Hip Arthroplasty for Acute Femoral Neck Fractures: Who Should Perform the Operation-Adult Reconstructive or Trauma Surgeons?

OBJECTIVE: To compare the results and complications of a large consecutive series of total hip arthroplasty (THA) performed for acute femoral neck (FN) fracture by adult reconstructive (AR) and trauma (T) surgeons to determine if there is a difference in outcomes. DESIGN: Retrospective chart review. SETTING: Level 1 trauma center. PATIENTS: One hundred forty-nine consecutive patients who presented to our institution with displaced FN fractures treated by THA were included in this study. INTERVENTION: All patients were treated with THA. MAIN OUTCOME MEASUREMENTS: Implant survival, 90-day complications, 90-day readmission, 1-year complications. RESULTS: For the group as a whole, the major surgical complication rate (defined as dislocation, deep infection, loosening, fracture) was significantly higher for T surgeons (20%) than for AR surgeons (7%) (P = 0.021). AR surgeons had significantly less radiographic component malpositioning 12% versus 3% (P = 0.024). Mortality and readmission rates were similar between the 2 cohorts at all time points. Implant survivorship was significantly higher at 1 year for AR surgeons (P = 0.05). CONCLUSIONS: THA for acute FN fracture performed by AR surgeons demonstrated higher rates of accurate radiographic component positioning, significantly lower major complication rates at 90 days and 1 year, and greater implant survival at 1 year. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Effect of Prenatal Repair of Myelomeningocele on Urological Outcomes at School Age.

PURPOSE: We investigated longer term urological outcomes in patients enrolled in the Management of Myelomeningocele Study (MOMS). MATERIALS AND METHODS: Women who participated in the original trial were asked for consent for followup for their child at age 6 years or older in a single comprehensive study visit to a MOMS center. Participating children underwent urological and radiologic procedures to provide objective evidence of current bladder functioning. Primary urological outcome was defined as any among need for clean intermittent catheterization, vesicostomy, urethral dilatation or augmentation cystoplasty. RESULTS: A total of 156 children were evaluated, with a mean age of 7.4 years. Overall 62% vs 87% in the prenatal and postnatal surgery groups, respectively, were placed on clean intermittent catheterization (RR 0.71, 95% CI 0.58-0.86, p <0.001). Voiding status was significantly different between the groups (p <0.001) as 24% in the prenatal group vs 4% in the postnatal group (RR 5.8, 95% CI 1.8-18.7) were reported to be voiding volitionally. Augmentation cystoplasty, vesicostomy and urethral dilation did not differ between the 2 groups. Aside from a larger post-void residual urodynamic catheterization volume, there were no other statistical differences in videourodynamic data or findings on renal/bladder ultrasound. CONCLUSIONS: Prenatal closure of myelomeningocele resulted in less reported clean intermittent catheterization at school age and the mechanism for this is unclear. Although most children are in diapers or on clean intermittent catheterization, parental reports showed children who underwent prenatal closure may be more likely to void volitionally than the postnatal group. Despite these findings, urological outcomes alone should not be the sole impetus to perform in utero closure in children with spina bifida.

Update on Continent Catheterizable Channels and the Timing of their Complications.

PURPOSE: We previously reported catheterizable channel associated outcomes and concluded that the incidence of postoperative complications was greatest in the first 2 years after surgery. At that time our followup was short. In this series we sought to determine whether complications continued to accumulate with longer followup in an updated cohort of patients. MATERIALS AND METHODS: We comprehensively reviewed the outcomes in 81 consecutive patients who underwent construction of a MACE (Malone antegrade continence enema) and/or a Mitrofanoff channel in association with complex genitourinary reconstruction. Mean followup was 80.1 months. Outcomes of these 119 stomas were classified by Clavien-Dindo grade and time to complication. RESULTS: The 48 unique, channel related events (40.3%) necessitated a total of 70 interventions with a mean 24.2 months to the first event. Difficult catheterization was the most common event, occurring in 20.1% of channels an average of 29.9 months after surgery. Stomal stenosis was also common, developing in 12.6% of channels at an average of 19.9 months after surgery. Unique complications clustered in the first 2 years, after which there was a statistically significant decline (p = 0.0013). High grade complications similarly clustered (p <0.0001). Channel composition was significantly associated with rates of difficult catheterization events. CONCLUSIONS: Compared to our previous cohort of patients with similar volume but shorter followup, our assumption that channel associated complications cluster postoperatively and then decrease significantly was correct. Our current and more detailed series demonstrates that the rate of postoperative complications decreases with time. However, with longer followup patients continue to experience lower grade events requiring fewer interventions.

Bladder Function After Fetal Surgery for Myelomeningocele.

BACKGROUND: A substudy of the Management of Myelomeningocele Study evaluating urological outcomes was conducted. METHODS: Pregnant women diagnosed with fetal myelomeningocele were randomly assigned to either prenatal or standard postnatal surgical repair. The substudy included patients randomly assigned after April 18, 2005. The primary outcome was defined in their children as death or the need for clean intermittent catheterization (CIC) by 30 months of age characterized by prespecified criteria. Secondary outcomes included bladder and kidney abnormalities observed by urodynamics and renal/bladder ultrasound at 12 and 30 months, which were analyzed as repeated measures. RESULTS: Of the 115 women enrolled in the substudy, the primary outcome occurred in 52% of children in the prenatal surgery group and 66% in the postnatal surgery group (relative risk [RR]: 0.78; 95% confidence interval [CI]: 0.57-1.07). Actual rates of CIC use were 38% and 51% in the prenatal and postnatal surgery groups, respectively (RR: 0.74; 95% CI: 0.48-1.12). Prenatal surgery resulted in less trabeculation (RR: 0.39; 95% CI: 0.19-0.79) and fewer cases of open bladder neck on urodynamics (RR: 0.61; 95% CI: 0.40-0.92) after adjustment by child's gender and lesion level. The difference in trabeculation was confirmed by ultrasound. CONCLUSIONS: Prenatal surgery did not significantly reduce the need for CIC by 30 months of age but was associated with less bladder trabeculation and open bladder neck. The implications of these findings are unclear now, but support the need for long-term urologic follow-up of patients with myelomeningocele regardless of type of surgical repair.

To tell or not: parental thoughts on disclosure of urologic surgery to their child.

PURPOSE: Literature pertaining to surgical disclosure to the pediatric patient is lacking. We hypothesized parents would find it difficult to disclose urologic surgery to a child. MATERIALS AND METHODS: Parents of patients <5 years old undergoing urologic surgery were contacted for telephone survey. Parents were asked about future plans of surgical disclosure, comfort with disclosure, and any support received. RESULTS: 98 parents consented to study participation. 87% of surgeries were on the genitalia with 62% being minor genitalia surgery (i.e. circumcision). 70% of parents would tell their child about minor genital surgery while 84% would tell about major genital surgery (p=0.07). 4 of 20 parents of children undergoing hypospadias repair (major genital surgery) did not plan to tell their child about surgery. All parents of children undergoing non-genital surgery would tell. Of all parents planning to tell their children about surgery, only 14% were nervous. 34% of parents would find guidance in talking to their child helpful despite the majority (90%) stating no guidance had ever been provided. CONCLUSIONS: Parents seem comfortable discussing urologic surgeries with a child but about 1/3 would appreciate further counseling. 20% of parents of children undergoing hypospadias repair hope to avoid telling their child.

To tell or not: parental thoughts on disclosure of urologic surgery to their child

Literature pertaining to surgical disclosure to the pediatric patient is lacking. We hypothesized parents would find it difficult to disclose urologic surgery to a child.

Long-term follow-up of children who underwent severe hypospadias repair using an online survey with validated questionnaires.

OBJECTIVE: Few studies of hypospadias repair in childhood have used validated questionnaires to investigate outcomes of cosmesis, urinary function, and sexual function in adulthood. We sought to investigate long-term outcomes in adult patients who had undergone severe hypospadias repair as children using an existing web-based application available to multiple institutions in order to develop an online patient survey of previously validated questionnaires. MATERIALS AND METHODS: Patients aged 18 years or older who underwent severe hypospadias repair between 1992 and 1997 at our institution were contacted to complete an online survey. Through medical chart reviews, we analyzed the location of meatus, type of repair, and complications. The online survey included questions about penile appearance, and validated questionnaires to assess urinary and sexual function. RESULTS: Of 58 patients who met the inclusion criteria, we contacted 19, and 13 completed the survey. Fifty-nine percent had complications, with an average of 2.2 procedures per patient. Most (85.0%) were satisfied with penile appearance, although 38.0% had residual penile curvature. Hypospadias patients had mean lower orgasmic function than normal controls. Mean scores for urinary function and other domains of sexual function were similar to normal controls. CONCLUSIONS: Although the majority of adult patients were satisfied with the outcomes of penile appearance, urinary function, and sexual function, our online survey suggests decreased lower orgasmic function as measured by validated questionnaire. An online survey accessible to multiple institutions with validated questionnaires may facilitate assessment of long-term hypospadias results.

Outcomes of incontinent ileovesicostomy in the pediatric patient.

PURPOSE: Ileovesicostomy is a reconstructive option in complex urological cases but pediatric specific outcomes are lacking. We report our results with pediatric ileovesicostomy. MATERIALS AND METHODS: We retrospectively evaluated patients younger than 18 years undergoing incontinent ileovesicostomy at Vanderbilt University. History, urinary tract management and operative course were reviewed in the electronic medical record. Particular attention was given to immediate and long-term postoperative complications. RESULTS: Nine patients underwent incontinent ileovesicostomy between 2000 and 2013 at a mean age of 10.3 years (range 1.4 to 15.5). Surgical indication was sequelae of neurogenic or nonneurogenic neurogenic bladder (such as infection or worsening hydronephrosis) in 5 patients, reversal of vesicostomy in 3 and closure of cloacal exstrophy in 1. All 9 patients were thought incapable of reliable clean intermittent catheterization due to family unwillingness, poor social support or patient refusal. Median followup was 11.5 months (mean 48.2, range 1.3 to 144.8). Immediate postoperative complications included ileus requiring total parenteral nutrition and a wound infection in 1 patient. Long-term complications included urinary tract infection in 2 patients (febrile in 1 and positive culture for foul smelling urine in 1), stomal issues in 2 and temporary urethral leakage in 1. Constipation affected 3 children in long-term followup (all with neurogenic bowel preoperatively). Postoperative creatinine was stable or improved in all patients. CONCLUSIONS: Ileovesicostomy is a viable approach in children left with few other options, particularly those who are noncompliant or physically/socially unable to handle catheterization. This operation can help keep such patients out of diapers.

Development of upper tract stones in patients with congenital neurogenic bladder.

OBJECTIVE: Patients with neurogenic bladder are at increased risk of developing upper tract stones. We hypothesized that patients with lower urinary tract stone disease are at greater risk of developing upper tract stones. METHODS: We performed a 10-year retrospective case-control study of patients with neurogenic bladder to determine the association between bladder and upper tract stones. Independent risk factors for upper tract stones were assessed. Cases and controls were matched 1:1. Univariable analysis was performed by Fisher's exact test and the Mann-Whitney U test. Multivariable logistic regression was performed. RESULTS: 52 cases and controls were identified. Cases were significantly more likely to be non-ambulatory, have bowel-urinary tract interposition, thoracic level dysraphism, and history of bladder stones. On multivariable analysis, independent predictors of stone formation were male sex (OR 2.82; p = 0.02), dysraphism involving the thoracic spine (OR 3.37; p = 0.014) bowel-urinary tract interposition (OR 2.611; p = 0.038), and a history of bladder stones (OR 3.57; p = 0.015). CONCLUSION: Patients with neurogenic bladder are at increased risk for upper tract stones. The presence of bladder stones may herald the development of upper tract stones. The predictors of stone disease identified should guide prospective studies to better understand the natural history of upper tract stone development in this population.

Differentiating amino acid residues and side chain orientations in peptides using scanning tunneling microscopy.

Single-molecule measurements of complex biological structures such as proteins are an attractive route for determining structures of the large number of important biomolecules that have proved refractory to analysis through standard techniques such as X-ray crystallography and nuclear magnetic resonance. We use a custom-built low-current scanning tunneling microscope to image peptide structures at the single-molecule scale in a model peptide that forms ß sheets, a structural motif common in protein misfolding diseases. We successfully differentiate between histidine and alanine amino acid residues, and further differentiate side chain orientations in individual histidine residues, by correlating features in scanning tunneling microscope images with those in energy-optimized models. Beta sheets containing histidine residues are used as a model system due to the role histidine plays in transition metal binding associated with amyloid oligomerization in Alzheimer's and other diseases. Such measurements are a first step toward analyzing peptide and protein structures at the single-molecule level.

Analysis of an intervention to reduce parental anxiety prior to voiding cystourethrogram.

PURPOSE: The voiding cystourethrogram (VCUG) is a common imaging test in pediatric urology that can be associated with anxiety in the child and parent. We hypothesized that education by mailed brochure would decrease pre-procedure parental anxiety. METHODS: Families of children scheduled for VCUG were randomized into an experimental group that was mailed an educational brochure about the VCUG and a control group. Immediately prior to the procedure, parental anxiety was assessed with the self-administered State-Trait Anxiety Inventory (STAI). The parent repeated the STAI at home after the VCUG and answered brief questions about educational resources used to prepare for the VUCG. RESULTS: We enrolled 105 families (47 experimental, 58 control). Parental state anxiety was higher before the procedure than after the procedure (p < 0.001). Younger parents had greater pre-procedure state anxiety (p = 0.007). Contrary to our expectations, pre-procedure state anxiety did not differ between control and experimental groups. However, parents in the experimental group demonstrated less anxiety with some individual items in the questionnaire. CONCLUSION: An educational brochure mailed to families prior to VCUG did not decrease pre-procedure parental state anxiety. However, the educational brochure can ensure accurate dissemination of information to help families prepare for this potentially distressing procedure.

Native Michigan plants stimulate soil microbial species changes and PAH remediation at a legacy steel mill.

A 1.3-acre phytoremediation site was constructed to mitigate polyaromatic hydrocarbon (PAH) contamination from a former steel mill in Michigan. Soil was amended with 10% (v/v) compost and 5% (v/v) poultry litter. The site was divided into twelve 11.89 m X 27.13 m plots, planted with approximately 35,000 native Michigan perennials, and soils sampled for three seasons. Soil microbial density generally increased in subplots of Eupatorium perfoliatum (boneset), Aster novae-angliae (New England aster), Andropogon gerardii (big bluestem), and Scirpus atrovirens (green bulrush) versus unplanted subplots. Using enumeration assays with root exudates, PAH degrading bacteria were greatest in soils beneath plants. Initially predominant, Arthrobacter were found capable of degrading a PAH cocktail in vitro, especially upon the addition of root exudate. Growth of some Arthrobacter isolates was stimulated by root exudate. The frequency of Arthrobacter declined in planted subplots with a concurrent increase in other species, including secondary PAH degraders Bacillus and Nocardioides. In subplots supporting only weeds, an increase in Pseudomonas density and little PAH removal were observed. This study supports the notion that a dynamic interplay between the soil, bacteria, and native plant root secretions likely contributes to in situ PAH phytoremediation.

Incidence of abnormal imaging and recurrent pyelonephritis after first febrile urinary tract infection in children 2 to 24 months old.

PURPOSE: The AAP (American Academy of Pediatrics) no longer recommends voiding cystourethrogram in children 2 to 24 months old who present with a first urinary tract infection if renal-bladder ultrasound is normal. We identified factors associated with abnormal imaging and recurrent pyelonephritis in this population. MATERIALS AND METHODS: We retrospectively evaluated children diagnosed with a first episode of pyelonephritis at age 2 to 24 months using de-identified electronic medical record data from an institutional database. Data included age at first urinary tract infection, gender, race/ethnicity, need for hospitalization, intravenous antibiotic use, history of abnormal prenatal ultrasound, renal-bladder ultrasound and voiding cystourethrogram results, urinary tract infection recurrence and surgical intervention. Risk factors for abnormal imaging and urinary tract infection recurrence were analyzed by univariate logistic regression, the chi-square test and survival analysis. RESULTS: We identified 174 patients. Of the 154 renal-bladder ultrasounds performed 59 (38%) were abnormal. Abnormal prenatal ultrasound (p = 0.01) and the need for hospitalization (p = 0.02) predicted abnormal renal-bladder ultrasound. Of the 95 patients with normal renal-bladder ultrasound 84 underwent voiding cystourethrogram. Vesicoureteral reflux was more likely in patients who were white (p = 0.003), female (p = 0.02) and older (p = 0.04). Despite normal renal-bladder ultrasound, 23 of 84 patients (24%) had dilating vesicoureteral reflux. Of the 95 patients with normal renal-bladder ultrasound 14 (15%) had recurrent pyelonephritis and 7 (7%) went on to surgical intervention. CONCLUSIONS: Despite normal renal-bladder ultrasound after a first pyelonephritis episode, a child may still have vesicoureteral reflux, recurrent pyelonephritis and the need for surgical intervention. If voiding cystourethrogram is deferred, parents should be counseled on these risks.