The Journal of Emergency Medicine, Vol. 46, No. 5, pp. 627–631, 2014 Copyright Ó 2014 Elsevier Inc. Printed in the USA. All rights reserved 0736-4679/$ - see front matter
http://dx.doi.org/10.1016/j.jemermed.2013.11.095
Clinical Communications: Pediatrics RECURRENT SEVERE ABDOMINAL PAIN IN THE PEDIATRIC PATIENT James L. Homme, MD* and Ashley A. Foster, MD† *Department of Pediatrics and Emergency Medicine, Mayo Clinic, Rochester, Minnesota and †Department of Emergency Medicine, University of California San Francisco, San Francisco, California Reprint Address: James L. Homme, MD, Department of Emergency Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905
, Abstract—Background: Ureteropelvic junction obstruction (UPJO) is a blockage occurring at the junction of the ureter and the renal pelvis. Pediatric patients with UPJO pose a diagnostic challenge when they present to the emergency department (ED) with severe recurrent abdominal pain if there is not a level of suspicion for this condition. Objectives: Our aim was to review presentation of UPJO to the ED, methods of diagnosis, and treatment of this common but often overlooked condition. Case Report: We report on 2 patients, a 9-year-old and 3-year-old, who had multiple presentations to health care providers and the ED with intermittent and recurrent abdominal pain. Subsequent testing, including ultrasound (US) and computed tomography (CT) with diuretic-recreated symptoms, revealed UPJO. Open pyeloplasty was performed, resulting in complete resolution of symptoms. Conclusions: UPJO is an important diagnosis to consider when patients present to the ED with recurrent abdominal pain. US can be helpful in suspecting the diagnosis, but often CT, magnetic resonance urography, or diuretic scintigraphy is required for confirmation. Diuretics can be used to aid diagnostic testing by reproducing abdominal pain at the time of imaging. Referral to a urologist for open pyeloplasty is definitive treatment for this condition. Ó 2014 Elsevier Inc.
INTRODUCTION Abdominal pain is one of the most common presenting complaints in the emergency department (ED) (1,2). Ten percent of school-aged children are affected by recurrent abdominal pain (3). A majority of these cases do not have organic pathology and are thought to be psychosocial (4). However, in a child with severe acute or intermittent abdominal pain, diagnostic tests may be warranted (4). Ureteropelvic junction obstruction (UPJO), a blockage occurring at the junction of the ureter and the renal pelvis, can cause intermittent abdominal pain and deserves consideration when a child presents to the ED with severe or recurrent abdominal pain. UPJO is the most common cause of antenatal and neonatal hydronephrosis, with an incidence of 1 per 1000 1500 births. Although there is a paucity of data about the incidence of pediatric UPJO, in a study of school-aged children, it was found to be the cause of recurrent abdominal pain in 1 of 100 (3,5). Ultrasonography can be an effective initial screening tool to evaluate for hydronephrosis before more invasive imaging for diagnosis of UPJO (6). Mercaptoacetyltriglycine (MAG-3) diuretic scintigraphy, diuretic renography, or computed tomography (CT) scan and magnetic resonance imaging better illuminate genitourinary anatomy and function and can reproduce obstructive symptoms, therefore, serving as more reliable imaging tools. The gold standard of treatment of
, Keywords—ureteropelvic junction obstruction; abdominal pain; hydronephrosis; emergency department; pediatrics
Dr. Foster was a student at the time the study was conducted.
RECEIVED: 22 February 2013; FINAL SUBMISSION RECEIVED: 29 October 2013; ACCEPTED: 17 November 2013 627
628
J. L. Homme and A. A. Foster
UPJO in the pediatric population remains open pyeloplasty (5). CASE REPORT Case 1 A 9-year-old female presented to the ED at the prompting of her primary care physician after 6 months of intermittent, colicky abdominal pain and multiple evaluations at an outside institution, and planned pediatric gastroenterologist consultation in a month. She had experienced episodes of lower quadrant and suprapubic abdominal pain that would come on suddenly, progress to severe pain, and last several hours with spontaneous resolution. Many episodes would have associated vomiting. As a result, she had missed many days of school during the year. She first visited the ED with a similar episode of abdominal pain. She denied fevers, nausea, vomiting, dysuria, flank pain, or change in stool pattern. Her pain was mainly suprapubic with increasing intermittent episodes of severe pain. Over-the-counter medications provided little relief. No clear triggers had been identified. Her medical history was remarkable only for the abdominal pain. Family history was positive for multiple relatives with irritable bowel syndrome. Notable physical examination findings included a mild tachycardia of 111 beats/min, which normalized as pain resolved. She was well hydrated and her abdominal examination was unremarkable—nontender throughout, no evidence of guarding or rebound, no hepatosplenomegaly was present, and no masses were appreciated. A urinalysis was normal and an abdominal x-ray study showed moderate stool with no evidence of obstruction. She was subsequently discharged with a diagnosis of constipation and placed on a bowel-softening regimen consisting of magnesium citrate followed by stool softener and laxative. Five days later she returned due to parental concerns that she was not producing much stool and had another episode of abdominal pain with associated nausea and vomiting. Her examination was believed to be consistent with constipation due to a generalized dullness to percussion in all quadrants and formed stool palpable on digital rectal examination. A sodium phosphate enema was provided, resulting in production of a small amount of stool. She was discharged with the diagnosis of constipation and recommendations to follow-up with a gastroenterologist and to continue her bowel regimen. Two weeks later she returned with recurrent abdominal pain and vomiting and was seen by a third provider in the ED. She reported a moderate degree of pain and her examination was completely normal except for some suprapubic and left lower quadrant tenderness. At this visit, a complete blood count with differential, glucose, electrolytes, liver and pancreatic enzymes, bilirubin, erythrocyte
sedimentation rate, and c-reactive protein were obtained. All studies were within normal limits except for a mildly elevated glucose. Urine dipstick was normal and subsequent serum b-hydroxybutyrate and glycosylated hemoglobin were normal. Pelvic and abdominal ultrasounds were obtained. The only detected abnormality was moderate left pyelocaliectasis (Figure 1) with ureteral dilatation to the mid abdomen without definite obstruction and normal ureteral jet. Based on these results, a followup appointment was arranged with a pediatric urologist in 1 week, in addition to her previously scheduled appointment with a gastroenterologist. The next day she returned to the ED and was seen by a fourth provider for severe abdominal pain and vomiting lasting < 2 h and resolving spontaneously. Based on the increasing frequency of episodes of abdominal pain, arrangements were made the following day for contrast CT followed by diuretic-enhanced CT urography. During the imaging studies, a diagnosis of ureteropelvic junction obstruction (UPJO) was confirmed, with both reproduction of the patient’s pain post diuretic administration and marked increase in renal pelvis and proximal ureteral dilatation (Figure 2). The patient subsequently underwent open surgical intervention and was found to have a localized stricture due to kinking of the ureter. The narrowed segment was excised and a reduction pyeloplasty was performed. Follow-up MAG-3 diuretic scintography showed fully preserved renal function. Case 2 A 3-year-old otherwise healthy male presented to his primary care physician with 5 months of intermittent abdominal pain associated with vomiting that seemed to be increasing in frequency. His mother noted that most events occurred at night and began with some anxious behaviors followed by complaints of generalized abdominal
Figure 1. Renal ultrasound. Arrow points to moderate pyelocaliectasis of the left kidney, with the borders of the kidney highlighted by + signs.
Ureteropelvic Obstruction
629
Figure 2. Computed tomography urogram demonstrates left renal pyelocaliectasis (A) and localized stricture of the left ureter (B). Diuretic administration produced marked increased dilatation of the renal pelvis (C, axial view; D, coronal view) with associated reproduction of severe abdominal pain.
pain (patient consistently points to his umbilicus) that increased in severity and was subsequently followed by nonbloody nonbilious vomiting. All events would spontaneously resolve during the course of 4 6 hours. In between the events, the patient had no gastrointestinal symptoms, no weight loss, and was having daily soft stools. No dietary triggers had been identified as a possible explanation of his symptoms. Growth curves, physical examination, and abdominal x-ray studies were within normal limits. A presumptive diagnosis of reflux vs. functional abdominal pain was made and the patient was initiated on a proton pump inhibitor. Five days later, he presented to the ED late in the evening with recurrence of his abdominal pain and vom-
iting. Family history was negative for migraines and for close relatives with inflammatory bowel or irritable bowel disease. On examination, the patient was anxious and irritable and unable to find a position of comfort. He was having periodic bouts of emesis consisting of digested food. The abdomen was not distended, nontender, and there were no masses or hernias. Testicles were descended with normal testicular lie. His story was concerning for acute pathology in the abdomen, such as small bowel intussuception, internal hernia, malrotation, UPJO, or superior mesenteric artery syndrome. An abdominal and pelvic CT scan with oral and IV contrast was ordered to try and obtain imaging during an episode of pain. The scan showed a mildly enlarged left kidney with a dilated
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renal pelvis, delayed nephrogram, and a crossing vessel at the left UPJ as the source of the UPJO (Figure 3). The patient was referred to pediatric nephrology. During the operative procedure, an aberrant artery and vein were found to be compressing the ureter and causing a narrowed segment. Operative management involved a resection of the narrowed segment followed by a reduction pyeloplasty. On follow-up, the patient had normal renal function and no additional episodes of pain. DISCUSSION Dilatation of the collecting system as a consequence of obstruction at the UPJ has historically been called Dietl’s crisis (7). Josef Dietl first described the clinical syndrome in 1864, linking ‘‘crisis’’ of abdominal pain to shifting of the kidney ureters and renal vessels, ultimately causing obstruction (8). UPJO has a male predominance, with the majority of obstructions occurring on the left side (observed in both our cases) (9). Up to half of children with UPJO have other associated nonrenal abnormalities (10). Pain is theorized to be a consequence of the rapid increase in intraluminal pressure of the collecting system (11). The precise cause of UPJO has yet to be determined. Possible etiologies have been separated into extrinsic and intrinsic categories. Extrinsic etiology may be associ-
Figure 3. Computed tomography scan showing moderately dilated right renal pelvis (upper arrow) and a crossing vessel obstructing the ureter (lower arrow).
ated with high insertion of a ureter or ‘‘high-riding ureter,’’ improper rotation of kidney and surrounding structures, or crossing lower pole renal vessels inhibiting proper flow of urine (case 2) (5). Examples of intrinsic causes include congenital narrowing of the proximal ureter (case 1) or abnormal peristalsis at the ureteropelvic junction (5,7,12). Although UPJO can present at any stage of life from prenatal to adulthood, symptoms may differ depending on the age of the patient (10). It is commonly diagnosed prenatally with discovery of fetal hydronephrosis on ultrasonography (5). In newborns and infants, obstruction is marked by a palpable mass in the abdominal area. Although a history of a precipitating event of large fluid load or medication-induced diuresis resulting in flank pain can occur in children, such as is common in adults, many children presenting with UPJO may only complain of vague abdominal pain with localization around the umbilical region (10,13,14). Additional presenting symptoms may include emesis, hematuria, hypertension, dysuria, or associated urinary tract infection (10,15,16). The intermittent nature, poor localization of symptoms, and often rapid return to a normal baseline state make UPJO particularly difficult to diagnose without a high level of suspicion. Abdominal pain can exist for years before a definitive diagnosis of UPJO is made (7,8,15,17). Both patients reported here had months of symptoms and multiple visits to providers with a primary gastrointestinal cause suspected as the underlying etiology. Earlier diagnosis of UPJO can prevent acute or chronic renal dysfunction (18). In cases of hydronephrosis secondary to UPJO, complications can include glomerulosclerosis, medullary dysplasia, or interstitial fibrosis, even after obstruction is surgically resolved (19). These abnormalities can cause development of a renal tubular concentration defect and, depending on length of time the obstruction was present, the defect might persist long after the obstruction is resolved (13). Although timing of surgical management of asymptomatic UPJO is somewhat controversial with regard to preservation of renal function, UPJO is surgically corrected shortly after diagnosis in the symptomatic patient to ameliorate pain crises. Currently, there are several radiologic imaging tools that can be used to diagnose UPJO, with no gold standard modality (20). Renal ultrasonography has been recommended as an efficient screening tool in the ED to detect hydronephrosis secondary to possible obstruction. However, ultrasound does not allow for functional evaluation of the kidney or fully illuminate possible causes of obstruction (6,15). Additionally, ultrasound can have a false-negative rate of detecting obstruction in up to 14% of cases (21). This high number has been reduced when patients were appropriately hydrated before the test or alternately by performing an ultrasound with
Ureteropelvic Obstruction
diuretic administration before testing. This would have undoubtedly assisted in earlier diagnosis of UPJO in one of our patients (case 1). Timing of the diagnostic test is also very important, as the affected collecting system and ureter might look normal if the test is performed when the child is asymptomatic (10). Therefore, although ultrasonography can be used as a first-line study, it should be viewed as ‘‘rule-in’’ rather than a ‘‘rule-out’’ study unless obtained during a pain crisis. Contrast-enhanced CT scanning with delayed urography can be utilized when alternative diagnoses are also considered for the source of abdominal pain (case 2). The diagnostic yield in the asymptomatic patient can be improved with diuretic administration and delayed imaging (case 1). MAG-3 diuretic scintigraphy is considered the ideal imaging study when UPJO is the primary entity of concern. This provides both anatomic and functional information, but is not typically available to the emergency physician. Additionally, magnetic resonance urography can be utilized for further clarification in complex anatomic situations. The gold standard of therapy for UPJO is open dismembered pyeloplasty. Since the first procedure was performed in 1949, the success rate of pyeloplasty has increased to > 95% (22). Additionally, this procedure can be performed in patients with more complex anatomy, including crossing or anomalous vessels. Although less invasive, laparoscopic pyeloplasty can be complicated in the pediatric population, and does not share the same success rate as its open counterpart (23). Strengths and Limitations To our knowledge, this is an uncommonly described presentation of abdominal pain in children. The cases present a unique view into possible diagnostic techniques for UPJO. This study has all the limitations of a case report, patients are managed in a noncontrolled environment, and results should not be generalized to a large patient population. CONCLUSIONS A diagnosis of UPJO is represented in a small but significant minority of children presenting to the ED with a complaint of abdominal pain. Due to the intermittent nature and vague presenting symptoms, lack of abnormal physical examination, or laboratory abnormalities, this diagnosis can go unrecognized for months to years while other etiologies, including functional abdominal pain, are pursued. Imaging studies are critical in making the diagnosis, but care must be taken when interpreting ‘‘normal’’ studies in patients who are asymptomatic or not adequately hydrated due to the dynamic nature of degree of obstruc-
631
tion. We present 2 cases of UPJO that illustrate the difficulty in diagnosis and the importance of a high level of suspicion of this entity for the emergency physician. REFERENCES 1. Tseng YC, Lee MS, Chang YJ, Wu HP. Acute abdomen in pediatric patients admitted to the pediatric emergency department. Pediatr Neonatol 2008;49:126–34. 2. Graff LG IV, Robinson D. Abdominal pain and emergency department evaluation. Emerg Med Clin North Am 2001;19:123–36. 3. Apley J. The child with recurrent abdominal pain. Pediatr Clin North Am 1967;14:63–72. 4. Ward HC, Brereton RJ. Pelviureteric junction obstruction and recurrent abdominal pain in childhood. Br J Surg 1989;76:818–9. 5. Williams B, Tareen B, Resnick MI. Pathophysiology and treatment of ureteropelvic junction obstruction. Curr Urol Rep 2007;8:111–7. 6. Godambe SA, Boulden T. The use of an emergency physiciandirected bedside ultrasound examination to clarify a diagnosis in an 8-year-old boy with chronic abdominal pain. Pediatr Emerg Care 2007;23:560–2. 7. Belman AB. Ureteropelvic junction obstruction as a cause for intermittent abdominal pain in children. Pediatrics 1991;88:1066–9. 8. Flotte TR. Dietl syndrome: intermittent ureteropelvic junction obstruction as a cause of episodic abdominal pain. Pediatrics 1988;82:792–4. 9. Johnston JH, Evans JP, Glassberg KI, Shapiro SR. Pelvic hydronephrosis in children: a review of 219 personal cases. J Urol 1977;117:97–101. 10. McCarthy DJ, Tuite RJ, Conners GP. Index of suspicion. Case 3. Ureteropelvic junction obstruction. Pediatr Rev 1995;16:223. 5. 11. Shokeir AA. Renal colic: pathophysiology, diagnosis and treatment. Eur Urol 2001;39:241–9. 12. Yiee JH, Johnson-Welch S, Baker LA, Wilcox DT. Histologic differences between extrinsic and intrinsic ureteropelvic junction obstruction. Urology 2010;76:181–4. 13. Reinberg Y, Gonzalez R. Upper urinary tract obstruction in children: current controversies in diagnosis. Pediatr Clin North Am 1987;34:1291–304. 14. Kelalis PP, Culp OS, Stickler GB, Burke EC. Ureteropelvic obstruction in children: experiences with 109 cases. J Urol 1971; 106:418–22. 15. Tsai JD, Huang FY, Lin CC, et al. Intermittent hydronephrosis secondary to ureteropelvic junction obstruction: clinical and imaging features. Pediatrics 2006;117:139–46. 16. Schulte-Bockholt A, Kugathasan S, Mesrobian HGO, Werlin SL. Ureteropelvic junction obstruction: an overlooked cause of cyclic vomiting. Am J Gastroenterol 2002;97:1043–5. 17. Byrne WJ, Arnold WC, Stannard MW, Redman JF. Ureteropelvic junction obstruction presenting with recurrent abdominal pain: diagnosis by ultrasound. Pediatrics 1985;76:934–7. 18. Onen A. An alternative grading system to refine the criteria for severity of hydronephrosis and optimal treatment guidelines in neonates with primary UPJ-type hydronephrosis. J Pediatr Urol 2007;3:200–5. 19. Yilmaz E, Guney S. Giant hydronephrosis due to ureteropelvic junction obstruction in a child: CT and MR appearances. Clin Imag 2002;26:125–8. 20. Penna FJ, Chow JS, Minnillo BJ, et al. Identifying ureteropelvic junction obstruction by fluorescence imaging: a comparative study of imaging modalities to assess renal function and degree of obstruction in a mouse model. J Urol 2011;185:2405–13. 21. Ebel KD, Bliesener JA, Gharib M. Imaging of uretero-pelvic junction obstruction with simulated diuresis with consideration of the reliability of ultrasonography. Pediatr Radiol 1998;18:54–6. 22. Hashim H, Woodhouse CRJ. Ureteropelvic junction obstruction. Eur Urol Suppl 2012;11:25–32. 23. Sweeney DD, Ost MC, Schneck FX, Docimo SG. Laparoscopic pyeloplasty for ureteropelvic junction obstruction in children. J Laparoendosc Adv Surg Tech A 2011;21:261–5.
http://dx.doi.org/10.1016/j.jemermed.2013.11.095
Clinical Communications: Pediatrics RECURRENT SEVERE ABDOMINAL PAIN IN THE PEDIATRIC PATIENT James L. Homme, MD* and Ashley A. Foster, MD† *Department of Pediatrics and Emergency Medicine, Mayo Clinic, Rochester, Minnesota and †Department of Emergency Medicine, University of California San Francisco, San Francisco, California Reprint Address: James L. Homme, MD, Department of Emergency Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905
, Abstract—Background: Ureteropelvic junction obstruction (UPJO) is a blockage occurring at the junction of the ureter and the renal pelvis. Pediatric patients with UPJO pose a diagnostic challenge when they present to the emergency department (ED) with severe recurrent abdominal pain if there is not a level of suspicion for this condition. Objectives: Our aim was to review presentation of UPJO to the ED, methods of diagnosis, and treatment of this common but often overlooked condition. Case Report: We report on 2 patients, a 9-year-old and 3-year-old, who had multiple presentations to health care providers and the ED with intermittent and recurrent abdominal pain. Subsequent testing, including ultrasound (US) and computed tomography (CT) with diuretic-recreated symptoms, revealed UPJO. Open pyeloplasty was performed, resulting in complete resolution of symptoms. Conclusions: UPJO is an important diagnosis to consider when patients present to the ED with recurrent abdominal pain. US can be helpful in suspecting the diagnosis, but often CT, magnetic resonance urography, or diuretic scintigraphy is required for confirmation. Diuretics can be used to aid diagnostic testing by reproducing abdominal pain at the time of imaging. Referral to a urologist for open pyeloplasty is definitive treatment for this condition. Ó 2014 Elsevier Inc.
INTRODUCTION Abdominal pain is one of the most common presenting complaints in the emergency department (ED) (1,2). Ten percent of school-aged children are affected by recurrent abdominal pain (3). A majority of these cases do not have organic pathology and are thought to be psychosocial (4). However, in a child with severe acute or intermittent abdominal pain, diagnostic tests may be warranted (4). Ureteropelvic junction obstruction (UPJO), a blockage occurring at the junction of the ureter and the renal pelvis, can cause intermittent abdominal pain and deserves consideration when a child presents to the ED with severe or recurrent abdominal pain. UPJO is the most common cause of antenatal and neonatal hydronephrosis, with an incidence of 1 per 1000 1500 births. Although there is a paucity of data about the incidence of pediatric UPJO, in a study of school-aged children, it was found to be the cause of recurrent abdominal pain in 1 of 100 (3,5). Ultrasonography can be an effective initial screening tool to evaluate for hydronephrosis before more invasive imaging for diagnosis of UPJO (6). Mercaptoacetyltriglycine (MAG-3) diuretic scintigraphy, diuretic renography, or computed tomography (CT) scan and magnetic resonance imaging better illuminate genitourinary anatomy and function and can reproduce obstructive symptoms, therefore, serving as more reliable imaging tools. The gold standard of treatment of
, Keywords—ureteropelvic junction obstruction; abdominal pain; hydronephrosis; emergency department; pediatrics
Dr. Foster was a student at the time the study was conducted.
RECEIVED: 22 February 2013; FINAL SUBMISSION RECEIVED: 29 October 2013; ACCEPTED: 17 November 2013 627
628
J. L. Homme and A. A. Foster
UPJO in the pediatric population remains open pyeloplasty (5). CASE REPORT Case 1 A 9-year-old female presented to the ED at the prompting of her primary care physician after 6 months of intermittent, colicky abdominal pain and multiple evaluations at an outside institution, and planned pediatric gastroenterologist consultation in a month. She had experienced episodes of lower quadrant and suprapubic abdominal pain that would come on suddenly, progress to severe pain, and last several hours with spontaneous resolution. Many episodes would have associated vomiting. As a result, she had missed many days of school during the year. She first visited the ED with a similar episode of abdominal pain. She denied fevers, nausea, vomiting, dysuria, flank pain, or change in stool pattern. Her pain was mainly suprapubic with increasing intermittent episodes of severe pain. Over-the-counter medications provided little relief. No clear triggers had been identified. Her medical history was remarkable only for the abdominal pain. Family history was positive for multiple relatives with irritable bowel syndrome. Notable physical examination findings included a mild tachycardia of 111 beats/min, which normalized as pain resolved. She was well hydrated and her abdominal examination was unremarkable—nontender throughout, no evidence of guarding or rebound, no hepatosplenomegaly was present, and no masses were appreciated. A urinalysis was normal and an abdominal x-ray study showed moderate stool with no evidence of obstruction. She was subsequently discharged with a diagnosis of constipation and placed on a bowel-softening regimen consisting of magnesium citrate followed by stool softener and laxative. Five days later she returned due to parental concerns that she was not producing much stool and had another episode of abdominal pain with associated nausea and vomiting. Her examination was believed to be consistent with constipation due to a generalized dullness to percussion in all quadrants and formed stool palpable on digital rectal examination. A sodium phosphate enema was provided, resulting in production of a small amount of stool. She was discharged with the diagnosis of constipation and recommendations to follow-up with a gastroenterologist and to continue her bowel regimen. Two weeks later she returned with recurrent abdominal pain and vomiting and was seen by a third provider in the ED. She reported a moderate degree of pain and her examination was completely normal except for some suprapubic and left lower quadrant tenderness. At this visit, a complete blood count with differential, glucose, electrolytes, liver and pancreatic enzymes, bilirubin, erythrocyte
sedimentation rate, and c-reactive protein were obtained. All studies were within normal limits except for a mildly elevated glucose. Urine dipstick was normal and subsequent serum b-hydroxybutyrate and glycosylated hemoglobin were normal. Pelvic and abdominal ultrasounds were obtained. The only detected abnormality was moderate left pyelocaliectasis (Figure 1) with ureteral dilatation to the mid abdomen without definite obstruction and normal ureteral jet. Based on these results, a followup appointment was arranged with a pediatric urologist in 1 week, in addition to her previously scheduled appointment with a gastroenterologist. The next day she returned to the ED and was seen by a fourth provider for severe abdominal pain and vomiting lasting < 2 h and resolving spontaneously. Based on the increasing frequency of episodes of abdominal pain, arrangements were made the following day for contrast CT followed by diuretic-enhanced CT urography. During the imaging studies, a diagnosis of ureteropelvic junction obstruction (UPJO) was confirmed, with both reproduction of the patient’s pain post diuretic administration and marked increase in renal pelvis and proximal ureteral dilatation (Figure 2). The patient subsequently underwent open surgical intervention and was found to have a localized stricture due to kinking of the ureter. The narrowed segment was excised and a reduction pyeloplasty was performed. Follow-up MAG-3 diuretic scintography showed fully preserved renal function. Case 2 A 3-year-old otherwise healthy male presented to his primary care physician with 5 months of intermittent abdominal pain associated with vomiting that seemed to be increasing in frequency. His mother noted that most events occurred at night and began with some anxious behaviors followed by complaints of generalized abdominal
Figure 1. Renal ultrasound. Arrow points to moderate pyelocaliectasis of the left kidney, with the borders of the kidney highlighted by + signs.
Ureteropelvic Obstruction
629
Figure 2. Computed tomography urogram demonstrates left renal pyelocaliectasis (A) and localized stricture of the left ureter (B). Diuretic administration produced marked increased dilatation of the renal pelvis (C, axial view; D, coronal view) with associated reproduction of severe abdominal pain.
pain (patient consistently points to his umbilicus) that increased in severity and was subsequently followed by nonbloody nonbilious vomiting. All events would spontaneously resolve during the course of 4 6 hours. In between the events, the patient had no gastrointestinal symptoms, no weight loss, and was having daily soft stools. No dietary triggers had been identified as a possible explanation of his symptoms. Growth curves, physical examination, and abdominal x-ray studies were within normal limits. A presumptive diagnosis of reflux vs. functional abdominal pain was made and the patient was initiated on a proton pump inhibitor. Five days later, he presented to the ED late in the evening with recurrence of his abdominal pain and vom-
iting. Family history was negative for migraines and for close relatives with inflammatory bowel or irritable bowel disease. On examination, the patient was anxious and irritable and unable to find a position of comfort. He was having periodic bouts of emesis consisting of digested food. The abdomen was not distended, nontender, and there were no masses or hernias. Testicles were descended with normal testicular lie. His story was concerning for acute pathology in the abdomen, such as small bowel intussuception, internal hernia, malrotation, UPJO, or superior mesenteric artery syndrome. An abdominal and pelvic CT scan with oral and IV contrast was ordered to try and obtain imaging during an episode of pain. The scan showed a mildly enlarged left kidney with a dilated
630
J. L. Homme and A. A. Foster
renal pelvis, delayed nephrogram, and a crossing vessel at the left UPJ as the source of the UPJO (Figure 3). The patient was referred to pediatric nephrology. During the operative procedure, an aberrant artery and vein were found to be compressing the ureter and causing a narrowed segment. Operative management involved a resection of the narrowed segment followed by a reduction pyeloplasty. On follow-up, the patient had normal renal function and no additional episodes of pain. DISCUSSION Dilatation of the collecting system as a consequence of obstruction at the UPJ has historically been called Dietl’s crisis (7). Josef Dietl first described the clinical syndrome in 1864, linking ‘‘crisis’’ of abdominal pain to shifting of the kidney ureters and renal vessels, ultimately causing obstruction (8). UPJO has a male predominance, with the majority of obstructions occurring on the left side (observed in both our cases) (9). Up to half of children with UPJO have other associated nonrenal abnormalities (10). Pain is theorized to be a consequence of the rapid increase in intraluminal pressure of the collecting system (11). The precise cause of UPJO has yet to be determined. Possible etiologies have been separated into extrinsic and intrinsic categories. Extrinsic etiology may be associ-
Figure 3. Computed tomography scan showing moderately dilated right renal pelvis (upper arrow) and a crossing vessel obstructing the ureter (lower arrow).
ated with high insertion of a ureter or ‘‘high-riding ureter,’’ improper rotation of kidney and surrounding structures, or crossing lower pole renal vessels inhibiting proper flow of urine (case 2) (5). Examples of intrinsic causes include congenital narrowing of the proximal ureter (case 1) or abnormal peristalsis at the ureteropelvic junction (5,7,12). Although UPJO can present at any stage of life from prenatal to adulthood, symptoms may differ depending on the age of the patient (10). It is commonly diagnosed prenatally with discovery of fetal hydronephrosis on ultrasonography (5). In newborns and infants, obstruction is marked by a palpable mass in the abdominal area. Although a history of a precipitating event of large fluid load or medication-induced diuresis resulting in flank pain can occur in children, such as is common in adults, many children presenting with UPJO may only complain of vague abdominal pain with localization around the umbilical region (10,13,14). Additional presenting symptoms may include emesis, hematuria, hypertension, dysuria, or associated urinary tract infection (10,15,16). The intermittent nature, poor localization of symptoms, and often rapid return to a normal baseline state make UPJO particularly difficult to diagnose without a high level of suspicion. Abdominal pain can exist for years before a definitive diagnosis of UPJO is made (7,8,15,17). Both patients reported here had months of symptoms and multiple visits to providers with a primary gastrointestinal cause suspected as the underlying etiology. Earlier diagnosis of UPJO can prevent acute or chronic renal dysfunction (18). In cases of hydronephrosis secondary to UPJO, complications can include glomerulosclerosis, medullary dysplasia, or interstitial fibrosis, even after obstruction is surgically resolved (19). These abnormalities can cause development of a renal tubular concentration defect and, depending on length of time the obstruction was present, the defect might persist long after the obstruction is resolved (13). Although timing of surgical management of asymptomatic UPJO is somewhat controversial with regard to preservation of renal function, UPJO is surgically corrected shortly after diagnosis in the symptomatic patient to ameliorate pain crises. Currently, there are several radiologic imaging tools that can be used to diagnose UPJO, with no gold standard modality (20). Renal ultrasonography has been recommended as an efficient screening tool in the ED to detect hydronephrosis secondary to possible obstruction. However, ultrasound does not allow for functional evaluation of the kidney or fully illuminate possible causes of obstruction (6,15). Additionally, ultrasound can have a false-negative rate of detecting obstruction in up to 14% of cases (21). This high number has been reduced when patients were appropriately hydrated before the test or alternately by performing an ultrasound with
Ureteropelvic Obstruction
diuretic administration before testing. This would have undoubtedly assisted in earlier diagnosis of UPJO in one of our patients (case 1). Timing of the diagnostic test is also very important, as the affected collecting system and ureter might look normal if the test is performed when the child is asymptomatic (10). Therefore, although ultrasonography can be used as a first-line study, it should be viewed as ‘‘rule-in’’ rather than a ‘‘rule-out’’ study unless obtained during a pain crisis. Contrast-enhanced CT scanning with delayed urography can be utilized when alternative diagnoses are also considered for the source of abdominal pain (case 2). The diagnostic yield in the asymptomatic patient can be improved with diuretic administration and delayed imaging (case 1). MAG-3 diuretic scintigraphy is considered the ideal imaging study when UPJO is the primary entity of concern. This provides both anatomic and functional information, but is not typically available to the emergency physician. Additionally, magnetic resonance urography can be utilized for further clarification in complex anatomic situations. The gold standard of therapy for UPJO is open dismembered pyeloplasty. Since the first procedure was performed in 1949, the success rate of pyeloplasty has increased to > 95% (22). Additionally, this procedure can be performed in patients with more complex anatomy, including crossing or anomalous vessels. Although less invasive, laparoscopic pyeloplasty can be complicated in the pediatric population, and does not share the same success rate as its open counterpart (23). Strengths and Limitations To our knowledge, this is an uncommonly described presentation of abdominal pain in children. The cases present a unique view into possible diagnostic techniques for UPJO. This study has all the limitations of a case report, patients are managed in a noncontrolled environment, and results should not be generalized to a large patient population. CONCLUSIONS A diagnosis of UPJO is represented in a small but significant minority of children presenting to the ED with a complaint of abdominal pain. Due to the intermittent nature and vague presenting symptoms, lack of abnormal physical examination, or laboratory abnormalities, this diagnosis can go unrecognized for months to years while other etiologies, including functional abdominal pain, are pursued. Imaging studies are critical in making the diagnosis, but care must be taken when interpreting ‘‘normal’’ studies in patients who are asymptomatic or not adequately hydrated due to the dynamic nature of degree of obstruc-
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tion. We present 2 cases of UPJO that illustrate the difficulty in diagnosis and the importance of a high level of suspicion of this entity for the emergency physician. REFERENCES 1. Tseng YC, Lee MS, Chang YJ, Wu HP. Acute abdomen in pediatric patients admitted to the pediatric emergency department. Pediatr Neonatol 2008;49:126–34. 2. Graff LG IV, Robinson D. Abdominal pain and emergency department evaluation. Emerg Med Clin North Am 2001;19:123–36. 3. Apley J. The child with recurrent abdominal pain. Pediatr Clin North Am 1967;14:63–72. 4. Ward HC, Brereton RJ. Pelviureteric junction obstruction and recurrent abdominal pain in childhood. Br J Surg 1989;76:818–9. 5. Williams B, Tareen B, Resnick MI. Pathophysiology and treatment of ureteropelvic junction obstruction. Curr Urol Rep 2007;8:111–7. 6. Godambe SA, Boulden T. The use of an emergency physiciandirected bedside ultrasound examination to clarify a diagnosis in an 8-year-old boy with chronic abdominal pain. Pediatr Emerg Care 2007;23:560–2. 7. Belman AB. Ureteropelvic junction obstruction as a cause for intermittent abdominal pain in children. Pediatrics 1991;88:1066–9. 8. Flotte TR. Dietl syndrome: intermittent ureteropelvic junction obstruction as a cause of episodic abdominal pain. Pediatrics 1988;82:792–4. 9. Johnston JH, Evans JP, Glassberg KI, Shapiro SR. Pelvic hydronephrosis in children: a review of 219 personal cases. J Urol 1977;117:97–101. 10. McCarthy DJ, Tuite RJ, Conners GP. Index of suspicion. Case 3. Ureteropelvic junction obstruction. Pediatr Rev 1995;16:223. 5. 11. Shokeir AA. Renal colic: pathophysiology, diagnosis and treatment. Eur Urol 2001;39:241–9. 12. Yiee JH, Johnson-Welch S, Baker LA, Wilcox DT. Histologic differences between extrinsic and intrinsic ureteropelvic junction obstruction. Urology 2010;76:181–4. 13. Reinberg Y, Gonzalez R. Upper urinary tract obstruction in children: current controversies in diagnosis. Pediatr Clin North Am 1987;34:1291–304. 14. Kelalis PP, Culp OS, Stickler GB, Burke EC. Ureteropelvic obstruction in children: experiences with 109 cases. J Urol 1971; 106:418–22. 15. Tsai JD, Huang FY, Lin CC, et al. Intermittent hydronephrosis secondary to ureteropelvic junction obstruction: clinical and imaging features. Pediatrics 2006;117:139–46. 16. Schulte-Bockholt A, Kugathasan S, Mesrobian HGO, Werlin SL. Ureteropelvic junction obstruction: an overlooked cause of cyclic vomiting. Am J Gastroenterol 2002;97:1043–5. 17. Byrne WJ, Arnold WC, Stannard MW, Redman JF. Ureteropelvic junction obstruction presenting with recurrent abdominal pain: diagnosis by ultrasound. Pediatrics 1985;76:934–7. 18. Onen A. An alternative grading system to refine the criteria for severity of hydronephrosis and optimal treatment guidelines in neonates with primary UPJ-type hydronephrosis. J Pediatr Urol 2007;3:200–5. 19. Yilmaz E, Guney S. Giant hydronephrosis due to ureteropelvic junction obstruction in a child: CT and MR appearances. Clin Imag 2002;26:125–8. 20. Penna FJ, Chow JS, Minnillo BJ, et al. Identifying ureteropelvic junction obstruction by fluorescence imaging: a comparative study of imaging modalities to assess renal function and degree of obstruction in a mouse model. J Urol 2011;185:2405–13. 21. Ebel KD, Bliesener JA, Gharib M. Imaging of uretero-pelvic junction obstruction with simulated diuresis with consideration of the reliability of ultrasonography. Pediatr Radiol 1998;18:54–6. 22. Hashim H, Woodhouse CRJ. Ureteropelvic junction obstruction. Eur Urol Suppl 2012;11:25–32. 23. Sweeney DD, Ost MC, Schneck FX, Docimo SG. Laparoscopic pyeloplasty for ureteropelvic junction obstruction in children. J Laparoendosc Adv Surg Tech A 2011;21:261–5.
