(Presentation by Dr. Lee)

Transcription

1 THE POSTERIOR ACOUSTIC SHADOW: EVALUATING STONE SIZE IN PEDIATRIC STONE FORMERS Franklin C. Lee MD 1, Jonathan D. Harper MD 1, Thomas S. Lendvay MD 1, Ziyue Liu PhD* 2, Barbrina Dunmire MS* 1, Manjiri Dighe MD* 1, Michael Bailey PhD* 1, Mathew D. Sorensen MD 1 1 Seattle, WA; 2 Indianapolis, IN (Presentation by Dr. Lee) Introduction: Unlike adult stone formers, ultrasound is often and sometimes exclusively used in both the initial diagnosis and the follow-up of pediatric stone formers. Ultrasound has been shown to consistently overestimate stone size. Our group has previously demonstrated that the posterior acoustic shadow is a more accurate predictor of true stone size in an in-vitro model. We sought to determine the prevalence and accuracy of the posterior acoustic shadow in a pediatric cohort. Methods: A retrospective analysis was performed of all pediatric stone patient encounters at a children s hospital over the last 10 years using the ICD-9 code for nephrolithiasis (592.0). All included subjects had a computed tomography (CT) scan and renal ultrasound within 3 months of each other obtained for an initial stone event. Stones had to be present on both imaging studies to be included. The size of the stone and posterior acoustic shadow were measured on ultrasound by a radiologist and then compared to stone size as determined by CT. Results: Of 633 charts reviewed, 37 patients with 49 kidney stones were included. Mean age was 13 ± 4 years with a mean BMI of 19 ± 6 kg/m 2. A posterior acoustic shadow was seen in 85% of stones evaluated. Measuring the stone directly resulted in an average overestimation of 1.2 ± 2.2 mm compared to measuring the acoustic shadow which resulted in an underestimation of 0.5 ± 1.7 mm. The acoustic shadow was found to be a significantly (p < 0.001) better predictor of true stone size. Conclusions: The posterior acoustic shadow was seen in the majority of stones. Measuring the shadow was a more accurate measure of true stone size and may provide valuable prognostic information to help guide clinicians in counseling families about surveillance or surgical management of renal stones. Source of Funding: NIH DK43881 and DK092197, and NSBRI through NASA NCC 9-58.

2 PILOT PROSPECTIVE STUDY COMPARING RADIATION EXPOSURE AFTER MAG3 AND DMSA IN DIAPER-AGED CHILDREN Elana Godebu M.D. M.Ed, Daniel Vinocur M.D.*, George Chiang M.D., Stephen Steuterman*, Sarah Marietti M.D.: San Diego, CA (Presentation to be made by Dr. Godebu) Introduction: Nuclear medicine imaging using 99m Tc-mercaptoacetyltriglycine (Mag3) and 99m Tc-dimercapto-succinic acid (DMSA) are commonly used diagnostic modalities in pediatric urology. Radiation exposure to patients is well described; exposure to caregivers and cohabitants has not been established. Technetium-99, used to label Mag3 and DMSA, has a 6 hour half life, is excreted in urine, and remains in the diaper of non-toilet trained children. The child in diapers who undergoes Mag3 or DMSA may pose an unsafe radiation risk to pregnant primary caregivers or young siblings. In this pilot study, we measure the average radiation exposure to the primary caregiver. Methods: We prospectively identified 16 diapered children aged 3 years or younger of which 6, 5, and 5 underwent DMSA, Mag3,and renal-bladder ultrasound (RBUS), respectively. The primary caregiver wore a Dosimeter (Instadose ) for 24 hours immediately following the study. Dosimeters were returned via mail and immediately read. We recorded the child s gender, ethnicity, age, weight, isotope dose, and indication for the study. We also measured direct exposure to 2 patients first post procedure diapers for 24 hours which were being stored in a lead container for disposal. Given small patient numbers in this pilot study, non parametric Mann- Whitney and Kruskal-Wallace tests were used to assess for significance using IBM SPSS Statistics for Windows (Version Armonk, NY: IBM Corp). Results: Standard weight-based doses of isotope for Mag3 or DMSA were administered with standard imaging procedures. There were no significant demographic differences. The mean dosimeter recording for DMSA was / mrem, for Mag3 was / mrem, and for RBUS was / (Figure 1), and there was no significant difference overall (p=0.387), or comparing DMSA vs RBUS (p=0.662), or Mag3 vs RBUS (p=0.310). Finally, the dosimeters placed beside 2 patients first post procedure diapers measured 24 and 68 mrem. Conclusion: A major limitation of this pilot study is the small number of patients; however, we quickly identified that exposure to ionizing radiation in each group was similar to background levels, despite confirmed radiation in the first post procedure diaper. Estimates of average radiation exposure vary by location, about mrem annually, or 1-2 mrem daily. Exposure from a chest xray is about 5 mrem, and about 2-5 mrem from a transatlantic flight, posing minimal increase in the risk of excess malignancy, well within the annual dose limitations for the adult public. This pilot study suggests that caregivers do not have an exposure to ionizing radiation from diapered children undergoing nuclear medicine studies above the background radiation, with similar exposures seen between children undergoing nuclear studies and ultrasounds. Further studies could potentially tease out a small difference between the groups; however it is unlikely to be clinically significant at these doses. Despite this, concerned caregivers could be prudent and avoid close proximity to the child in the first few hours and/or to the first or first few changed diapers in order to achieve exposure that is as low as reasonably achievable (ALARA). Source of Funding: None

3 RISK FACTORS FOR STONE FORMATION IN CHILDREN USING LITHOLINK 24 HOUR URINE COLLECTIONS Ross Wopat, MD, Aaron Bayne, MD Department of Urology, Oregon Health Sciences University, Portland Oregon Purpose: The incidence of pediatric nephrolithiasis has been slowly climbing over the last decade accounting for a great number of hospitalizations and surgeries. We hypothesized that this increase is related to increasing body mass index in the pediatric population and that urine composition can accurately determine stone composition. Methods: Retrospective analysis from of all patients with identified pediatric urolithiasis and who underwent 24 hour urine collection using the Litholink urine analysis. Patients with known anatomic anomalies were excluded as well as patients with known secondary causes of stones, indwelling catheters, or prior urinary tract reconstruction. Urolithiasis must be documented by collection of a stone or visualization on imaging of the stone. Only the first urinalaysis was used. Patients were evaluated by BMI, type of stone, age, gender, family history, type of stone, and all urine collected data points. Results: 57 patients were eliglble from the entire set of patients who submitted litholinks at our institution during this time. Gender and family history were not predictive of stone formation. 13 patients were obese and 23 (41%) were considered overweight by BMI. 39 (68%) were under 10 years old. The most common metabolic urine abnormality was hypercalciuria but the most common risk factor was low urine output. Obese patients compared to normal patients had low urine volume (77% vs 43%, p=0.05) and elevated ssua (46% vs 13%, p= 0.04). Young children age < 10 had hypercalciuria more often (p=0.04) and had higher urine ph (p=0.03). Younger children rarely had low urine output as a risk factor (p <0.01) and had a much higher incidence of phosphate containing stones (p=0.04). Conclusion: Obese children do not make up a greater burden of the stone forming population but they do tend to have lower urine output and higher supersaturiation of Uric acid which may become more significant as they age. Younger children are at greatest risk for metabolic derangements and are unlikely to be managed with simple changes in fluid intake.

4 LOWER URINARY TRACT FUNCTION SCALE FOR BLADDER EXSTROPHY PATIENTS Ericka Sohlberg *, Steven J. Skoog, MD, Aaron P. Bayne, MD, J. Christopher Austin, MD. Portland, OR (Presentation is to be made by Ericka Sohlberg) Purpose: Definitions of continence for patients with bladder exstrophy vary among studies and make comparisons difficult. Furthermore patients may be excluded from their cohorts if they require bladder augmentation or never develop an adequate bladder capacity. We propose a lower tract function scale which accounts for these outcomes to better define the outcomes of all patients with bladder exstrophy. The scale uses complete continence with volitional voiding as the optimal outcome and severe incontinence or the need for reconstructive procedures (such as appendicovesicostomy or bladder augmentation) as worse outcomes. The spectrum between is defined using a Likert scale of 1-5. Methods: Medical records of bladder exstrophy patients with bladder closures performed at our institution from 1992 and 2011 were reviewed. Lower Urinary Tract Function was reported using the scale below: 1 Dry interval >2hrs No pad/diaper use, no day or night incontinence 2 Dry interval >2hrs No pad/diaper use, no daytime incontinence 3 Dry interval >2hrs <2 daytime accidents/week 4 Dry interval >2hrs Catheterization to empty bladder or prior APV 5 Dry interval <2hrs Continuous need for pad/diaper Results: 14 patients had bladder closure at our institution. At last followup, 6 needed augmentation (43%) and due to the need for CIC, all had a score of 4. Mean continence score for the cohort was 4.4. None had perfect continence. Overall, 43% had a continence score of 5, 50% 4, and 7% 3. Conclusions: Lower urinary tract function was poor overall for this cohort. The proposed lower urinary tract function scale would allow direct objective comparisons of outcomes between centers.

5 PERINEAL VASCULAR ANOMALIES IN CHILDREN: 35 YEARS OF EXPERIENCE Katie H. Willihnganz-Lawson, MD, Jennifer McClure, BS*, Margarett Shnorhavorian, MD, MPH, Jonathan A. Perkins, DO: Seattle, WA Purpose: Perineal and genitourinary vascular malformations are rare and often misdiagnosed. Without treatment they can affect urinary, sexual, reproductive and psychological function. Some vascular anomalies can also be associated with concomitant genitourinary defects such as PELVIS syndrome (perineal hemangioma, external genitalia malformations, lipomyelomeningocele, vesicorenal abnormalities, imperforate anus, and skin tag) that can complicate the timing of surgical resection. This reported experience is one of the largest cohorts reviewed, including both males and females. Our goal was to review the experience at our institution with genitourinary vascular anomalies, and discuss how the diagnosis and management approach has changed over time. Materials and Methods: Retrospectively reviewed 89 cases of genitourinary vascular anomalies managed at Seattle Children s Hospital from (17 cases from , 22 cases from , 30 cases from ). We analyzed the initial presentation, accuracy of the referring diagnosis, and approach to management including observation, medical therapy or surgical treatment. We also evaluated follow-up, recurrence rates, and long-term outcomes, comparing our historical cohort to current cohorts to evaluate trends. Results: Of the 89 patients, 64 female and 25 male, the primary presenting diagnoses were vascular malformation (n=25) and vascular hemangioma (infantile, congenital) (n=14). Of the single vessel type vascular malformations there were venous (n=6), capillary (n=4), and lymphatic (n=5) subtypes. Thirtytwo patients presented with single lesions the primary locations, perineum (n=32), labia (n=26), scrotum (n=5), and penis (n=2). Thirteen patients presented with multiple diffuse lesions, secondary locations included the face (n=4), chest (n=4), and extremities (n=8). Cases were associated with diagnoses of Klippel Trenaunay Syndrome (n=2), rapidly involuting congenital hemangioma (RICH) (n=2), cutis marmorata (n=1), and macrocephaly-capillary malformation (M-CM) syndrome (n=1). Each patient is carefully evaluated with imaging, diagnosed appropriately, and with close follow-up appropriate treatment regimen is determined. Comparison of current to historical cohorts, medical therapies with propranolol and sirolimus have replaced surgical treatment options as durable, safe, effective alternatives. Conclusions: Early treatment for vascular anomalies is standard, but there has been a shift away from surgical resection to medical management as the mainstay of treatment over the study period. Our long-term outcomes over with this change in management have shown good results with low recurrence rate. Source of Funding: None

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