Intermittent Ureteropelvic Junction Obstruction Can Mimic Abdominal Migraine: A Case Report and Review of the Literature

ABSTRACT

Recurrent abdominal pain poses a diagnostic challenge in the pediatric population. Functional and structural etiologies can contribute to this condition. The organic etiologies of recurrent abdominal pain are diagnoses of exclusions and considering them as the initial diagnosis could lead to mis‐ or delayed diagnosis with potentially several clinical consequences. Intermittent ureteropelvic junction obstruction (UPJO) is one of the structural etiologies of recurrent abdominal pain that could mimic the clinical presentation of functional etiologies. The absence of radiologic evidence of intermittent UPJO in the interval between the attack episodes makes it a diagnostic challenge, especially in the initial stages. This underscores the value of imaging evaluation during abdominal pain episodes or performing diuretic‐enhanced imaging modalities to capture the structural changes between the episodes. This study comprehensively discussed the diagnostic challenges associated with pediatric intermittent UPJO. We also present a known case of recurrent abdominal pain initially diagnosed as abdominal migraine, which was later reclassified as intermittent UPJO. Moreover, we reviewed the conventional diagnostic approaches in identifying the presence of structural etiologies in intermittent UPJO.

Summary.

• This study highlights the consequences of initially diagnosing recurrent abdominal pain with functional etiologies.

• It underscores the importance of using imaging modalities during pain episodes or performing diuretic‐enhanced imaging in the intervals between the pain episodes.

Abbreviations

^99mTc‐DTPA

^99mTechnetium‐diethylene triamine penta‐acetic acid

⁹⁹Tc‐DMSA SPECT

^99mTechnetium‐dimercaptosuccinic acid single‐photon emission computed tomography

⁹⁹Tc‐EC

^99mTechnetium‐ethylene dicysteine

AM

abdominal migraine

APD

anteroposterior diameter

CAKUT

congenital anomalies of the kidney and urinary tract

CT

computed tomography

CVS

cyclical vomiting syndrome

DMSA Scan

dimercaptosuccinic acid scan

DRF

differential renal function

EC Scan

ethylene dicysteine scan

EEG

electroencephalography

FGIDs

functional gastrointestinal disorders

GERD

gastroesophageal reflux disease

HSK

horseshoe kidney

ICHD‐3

International Classification of Headache Disorders 3

MAG‐3

mercaptoacetyltriglycine

MRI

magnetic resonance imaging

MRU

magnetic resonance urography

UPJO

ureteropelvic junction obstruction

US

ultrasonography

UTI

urinary tract infection

VUR

vesicoureteral reflux

1. Introduction

Recurrent abdominal pain in children poses a diagnostic challenge with a significant impact on the quality of life. It can be classified into organic and non‐organic categories [1]. Psychogenic etiologies are more common, with only 10% of cases attributed to organic causes [2]. Based on the Rome IV and the International Classification of Headache Disorders 3 (ICHD‐3) criteria, patients who experience recurring episodes of abdominal pain, nausea, and vomiting, followed by symptom‐free periods and normal clinical examinations, are considered to be diagnosed as either abdominal migraine (AM) or cyclical vomiting syndrome (CVS) [3]. Intermittent ureteropelvic junction obstruction (UPJO) is another differential diagnosis that can present with the aforementioned symptoms. It holds significant clinical importance in pediatric patients and is often overlooked in patients without other urologic symptoms.

UPJO is a narrowing of the junction between the renal pelvis and the ureter, with an incidence ranging from 1 in 1500 to 500. Males are predominantly affected, with a male‐to‐female ratio of 2:1 [4]. Congenital and acquired etiologies can lead to UPJO, although most cases are congenital and often remain asymptomatic until late childhood or adulthood. Improvements in imaging modalities have led to earlier diagnosis and prevent loss of renal function. In the setting of recurrent severe abdominal pain with an underlying intermittent UPJO, that is, Dietl's crisis, ultrasonography remains the diagnostic cornerstone, especially in the duration of pain; however, during the symptom‐free intervals, performing diuretic‐enhanced ultrasound to reinitialize the hydronephrosis might be necessary and confirm the diagnosis [5, 6].

Dietl's crisis is a clinical syndrome of intermittent UPJO characterized by episodes of abdominal pain, nausea, and vomiting, which subsequently leads to delayed drainage and hydronephrosis [7, 8]. Increased fluid intake will exacerbate intermittent UPJO due to rapid hydronephrosis and induction of pressure in the collecting system, a physical stretch of the renal capsule, and activation of nerve endings in the lamina propria, which ultimately causes pain episodes [8, 9]. The renal pelvis anteroposterior diameter (APD) significantly expands during episodes and returns to normal measures when the pain is alleviated [10]. Hence, non‐specific clinical manifestations in patients with intermittent UPJO, accompanied by symptom‐free intervals, lead to misdiagnosis or neglect of the condition. Meanwhile, timely diagnosis and management of the obstruction would eliminate the symptoms and prevent deterioration of renal function [11].

Here, we report a case with intermittent UPJO initially diagnosed as AM due to normal clinical and radiological findings in the intervals between abdominal pain episodes. A comprehensive review of traditional diagnostic methods was discussed to enhance diagnostic options for pediatric recurrent abdominal pain.

2. Case History/Examination

A 5‐year and 7‐month‐old girl with a past medical history of horseshoe kidney (HSK), recurrent urinary tract infections (UTIs), recurrent abdominal pain, and cyclic vomiting had been referred to the urology clinic for evaluation of urinary tract abnormalities. The patient experienced recurrent abdominal pain, nausea, and cyclic vomiting since the age of 7 months. The cyclic episodes of abdominal pain were characterized as non‐radiating cramping sensations with periumbilical pain, attended by non‐hematemesis vomiting, which required hospitalization 11 times. The investigations during the hospitalization period at that age confirmed UTI and HSK without any evidence of stone or obstruction. Since age two, the patient had been under prophylactic antibiotic therapy for UTI, but the abdominal pain crisis hadn't been resolved, and gastroesophageal reflux disease (GERD) was diagnosed based on performed gastrointestinal endoscopy. However, the cyclic symptoms persisted despite the patient being prescribed the proton pump inhibitors medication and lifestyle modification. Considering the family history of migraines in the second‐degree maternal relative, the persistence of cyclic abdominal pain and vomiting, and normal findings of brain magnetic resonance imaging (MRI) and electroencephalography (EEG), AM was considered as a potential diagnosis. The patient was prescribed amitriptyline, a tricyclic anti‐depressant medication that is also used in the treatment of pain syndromes and migraines. Still, the episodic symptoms of abdominal pain, nausea, and vomiting persisted, while all diagnostic tests like urine analysis and the US have been normal in each hospitalization.

3. Differential Diagnosis, Investigations and Treatment

After referring to the urology clinic, the first diagnostic approach was a renal bladder US, which depicted HSK with an abnormal external rotation of renal pelvises and moderate to severe left hydroureteronephrosis with an APD of 36 mm without any regression in the post‐void diameter. In the following steps, magnetic resonance urography (MRU) findings also suggest obstruction at the level of the left ureteropelvic junction (UPJ) (Figure 1). Due to UTI history, ^99mTechnetium‐dimercaptosuccinic acid single‐photon emission computed tomography (^99mTc‐DMSA SPECT) and ^99mTechnetium‐pertechnetate direct cystography were performed to evaluate the cortical renal function and presence of vesicoureteral reflux (VUR), respectively, which indicated the left renal perfusion reduction and absence of VUR. To further investigate the underlying cause of non‐reducing post‐void left hydronephrosis, a diuretic renal scan with ^99mTechnetium‐ethylene dicysteine (^99mTc‐EC) and furosemide‐enhanced ultrasonography was performed. As shown in Figure 2, Tc‐EC scan findings indicated marked left hydronephrosis more prominent in the upper pyelocaliceal system with moderate to severe decreased function of the left kidney suggestive of left UPJO. The furosemide‐enhanced ultrasonography findings depicted an increase in the APD of the left renal pelvis from 24 to 43 mm 20 min after diuretic injection (Figure 3), confirming intermittent UPJO diagnosis.

FIGURE 1.

The MRU of the patient demonstrates evidence of horseshoe kidneys with severe hydronephrosis of left renal pelvis with the anteroposterior diameter of 30 mm, suggestive of left ureteropelvic junction obstruction.

FIGURE 2.

This figure represents the 99Tc‐EC scan of the patient before surgical intervention. (A) The postvoid frame of the diuretic‐enhanced renal scan depicting non‐reducing characteristics of left renal pelvis anteroposterior diameter at the level of ureteropelvic junction. (B) The kidney–ureter drainage curve graph represents left side obstruction of ureteropelvic junction. The curve colored in red is representative of the left ureter drainage curve.

FIGURE 3.

Lasix‐enhanced ultrasonography demonstrates evidence of severe increase in anteroposterior diameter of left renal pelvis after diuretic injection. (A) The ultrasonographic presentation of left kidney before Lasix injection, the left renal pelvis anteroposterior diameter measured as 24 mm. (B) The ultrasonographic presentation of left kidney 20 min after Lasix injection demonstrated the increase in the severity of hydronephrosis in the left kidney with a measured anteroposterior diameter of 43 mm.

4. Conclusion and Results (Outcome and Follow‐Up)

The patient underwent left‐sided Anderson's Hynes pyeloplasty, where the intra‐operative observations suggested UPJO due to aberrant vessels. The patient was discharged with no postoperative complications on postoperative day four with nephrostomy and double‐J stent in place. The nephrostomy was removed 2 weeks after discharge. Over the 2‐year postoperative follow‐ups, the patient did not experience any intermittent abdominal pain, nausea, and vomiting. Postoperative US imaging revealed a decreasing trend in the APD of the left renal pelvis to 15 and 7 mm in the first and second postoperative years, respectively (Figure 4).

FIGURE 4.

The post‐operative ultrasonography of the left kidney revealed the measured anteroposterior diameter of 7 mm.

5. Discussion

Recurrent abdominal pain is a widespread issue in pediatric cases, primarily associated with functional gastrointestinal disorders (FGIDs) [12]. AM contributes to such pain, with prevalence varying between 2.4% and 4.1% [1]. In pediatric cases, AM is characterized by episodic central abdominal pain lasting over an hour, significantly affecting daily activities. Associated symptoms may include pallor, anorexia, nausea, vomiting, photophobia, headache, or other episodic syndromes. All physical examinations and diagnostic tests should yield normal results to confirm the diagnosis [3]. Following the Rome IV or ICHD III criteria, ruling out alarming symptoms is sufficient for a primary diagnosis of AM, which enables the initiation of effective treatment [13]. The patient's response to the prescribed treatment is critical to confirm the diagnosis; otherwise, it may suggest an underlying complication, which necessitates a more comprehensive reassessment [14]. As seen in our patient, the recurrence of attacks and the lack of response to pharmacological treatment led to further evaluations; given the history of HSK, examination of the urinary system has been prioritized as part of the evaluation. HSK is a congenital anomaly, with an incidence of 1 in 500 individuals, with a higher prevalence among males at a ratio of 2:1 [15, 16]. HSK typically presents asymptomatic as an incidental finding. Symptomatic cases commonly manifest as abdominal pain, nausea, and vomiting, often due to complications such as nephrolithiasis, UTI, anatomical abnormalities, and aberrant vessels leading to obstruction [17, 18, 19]. In HSK, the fused lower poles of the kidneys are situated near the body's midline. The renal pelvis often is anteriorly displaced due to the fusion, the ureter is highly inserted into the pelvis, and in some cases, the ureter is crossed over the isthmus of the fused kidney or is pressured by an aberrant vessel, which all can contribute to delayed emptying and obstruction in the upper urinary tract and UPJO [15]. The important point is that this obstruction is not permanent, and so are the symptoms. It would disappear after complete emptying or in a condition of low or normal urine filtration, presenting as episodic obstruction called intermittent UPJO.

Intermittent UPJO is typically caused by an aberrant accessory renal artery or vein, as in HSK. It causes a unique clinical syndrome characterized by severe episodic abdominal pain, nausea, and vomiting, along with intermittent hydronephrosis, which is referred to as Dietl's crisis [7, 8, 11]. Since this medical condition can present as cyclic syndromes, such as CVS or AM, and a lack of associated urologic symptoms, a child with this crisis often has a delay in diagnosis and late referral to a pediatric urologist [9]. The literature reports several cases of intermittent UPJO where patients initially received a diagnosis of functional or psychogenic abdominal pain due to overlapping non‐specific gastrointestinal symptoms (Table 1). These symptoms and the normal depiction of the urinary tract in imaging modalities, especially obtained in symptom‐free intervals, contribute to the diagnostic challenge [2, 7, 8, 9, 10, 11, 20, 21, 22, 23, 24, 25, 26, 27, 28].

TABLE 1.

A summary of patients with intermittent UPJO with an initial presentation or diagnosis of functional or psychogenic abdominal pain.

Study	Type of study	Participant	Clinical presentation	Initial presentation/diagnosis	Diagnostic modality
Lahoud et al. (2021) [7]	Case report	7‐year‐old boy with left UPJO	Colicky left flank pain with nausea and vomiting	Colicky abdominal pain	US, diuretic renography, MRU
Maddileti et al. (2021) [9]	Case report	A 2‐month‐old boy and a 6‐year‐old girl with intrinsic unilateral UPJO	Pain and one‐side abdominal fullness	Not mentioned	US before and after the crisis, dynamic scintigraphy
Fox et al. (2020) [20]	Case report	A 4‐year‐old girl with UPJO secondary to HSK	Recurrent abdominal pain, vomiting, and fatigue	Constipation	Point‐of‐care US
Chen et al. (2020) [10]	Retrospective cohort	150 patients with unilateral UPJO (119 intrinsic ureteral narrowing, 21 fibroepithelial polyps, seven crossing vessels, three high insertions of ureter)	Children with prenatally detected hydronephrosis can develop Dietl's Crisis at an earlier age	Not mentioned	US during symptomatic and asymptomatic
Noble et al. (2020) [21]	Case report	A 7‐year‐old boy with left UPJO due to crossing a vessel	Periumbilical, non‐radiating abdominal pain with nonbilious, non‐bloody emesis	Chronic constipation	US before and after pain episode, CT scan
Burhop et al. (2016) [22]	Case report	A 7‐year‐old girl with left UPJO due to crossing a vessel	Abdominal pain and vomiting, subjective fever, and anorexia	Constipation	US, CT scan
Godambe et al. (2007) [23]	Case report	An 8‐year‐old boy with left UPJO due to crossing a vessel	Periumbilical abdominal pain and anorexia without vomiting	Not mentioned	US, CT scan with intravenous contrast
Tsai et al. (2006) [8]	Prospective cohort	18 patents with intermittent UPJO (six intrinsic ureteral narrowing, six kinked ureter, two high insertions of ureter, one crossing vessel, two fibroepithelial polyps)	Most had sharp pain that began acutely and most (16 of 18) had nausea and vomiting	One intestinal ileus, one appendicitis, one abdominal mass, two renal stones, one chronic constipation, two gastrointestinal dysfunctions, and one urinary tract infection	Serial US studies, 99mTc‐DTPA diuretic renal scan
Alagiri et al. (2006) [2]	Retrospective cohort	Eight patients with intermittent UPJO	Severe, episodic, periumbilical pain associated with nausea and vomiting and a hydronephrotic kidney	One misdiagnosed as psychogenic pain for a long time resulted in hydronephrosis with extensive intrapelvic and perirenal hemorrhage necessitating nephrectomy	CT scan, diuretic renal scan
Bockholt et al. (2002) [11]	Case series	Four patients (3‐, 4‐, 6‐, 7‐year‐old boys) with intermittent UPJO	All patients with recurrent periumbilical pain and vomiting	CVS, abdominal migraine	US, CT, IVP
Byrne et al. (1985) [24]	Case report	7‐ and 9‐year‐old boys (with high insertion of ureter) and 14‐year‐old girl (with intrinsic ureteral narrowing) with intermittent UPJO	Episodes of periumbilical abdominal pain associated with vomiting	Abdominal epilepsy, functional abdominal pain	US, diuretic renogram
Reza S. Malek (1983) [25]	Prospective cohort	Ten patients with intermittent UPJO	Recurrent pain in the flank or abdomen	Psychologic pain	Excretory urography
Kelalis et al. (1971) [26]	Prospective cohort	109 patients with intermittent UPJO	Vague abdominal pain with cyclical vomiting	Appendicitis in three patients (even they had been under appendectomy surgery)	IVP
Kendall et al. (1967) [27]	Case report	22‐ and 28‐year‐old woman with UPJO due to aberrant vessel	Intermittent flank pain	Functional abdominal pain	Excretory urography
Reed M. Nesbit (1956) [28]	Case series	Five adult patients with intermittent UPJO due to aberrant vessel	Recurrent attacks of pain in the left upper abdomen with nausea and vomiting	Not mentioned	IVP during and prior to the pain episode

Abbreviations: ^99mTc‐DTPA, ^99mTechnetium‐diethylene triamine penta‐acetic acid; CT, computed tomography; CVS, cyclic vomiting syndrome; HSK, horseshoe kidney; IVP, intravenous pyelography; MRU, magnetic resonance imaging; UPJO, ureteropelvic junction obstruction; US, ultrasonography.

Improvements in the US, specifically prenatal ultrasound, have changed the diagnosis and management of UPJO over the last couple of decades [29]. Approximately 40% of pediatric patients with intermittent UPJO have been reported to have a history of prenatal hydronephrosis, and interestingly, these patients were significantly younger when experiencing their first Dietl's crisis [10].

The presence of hydronephrosis in HSK patients is a predictable US finding and distinguishing it from UPJO can be misleading. While the US remains a valuable initial screening tool, complementation of the US findings with the diuretic‐enhanced US or renal scan is essential. In the presented case, a normal interpretation of the patient's ultrasound during pain‐free intervals covered the necessity of further urological evaluation. According to the literature, diuretic‐enhanced scans, such as Mercaptoacetyltriglycine (MAG‐3) and ^99mTc‐EC, remain indispensable for definitively confirming or ruling out UPJO [20, 30]. Fox et al. reported a 4‐year‐old girl with intermittent UPJO secondary to HSK, with mild hydronephrosis between episodes of abdominal pain and an initial diagnosis of constipation. The hydronephrosis in the US during an episode of abdominal pain demonstrated the hydronephrosis progression from mild to severe. The diagnosis of intermittent UPJO following HSK was further confirmed by repeated US, nuclear renal scan, and voiding cystourethrogram [20].

The importance of imaging during abdominal pain attacks to diagnose intermittent UPJO was made by Nesbit et al. in 1957, reporting five adult cases of abdominal pain triggered by extensive fluid intake where only pyelography during the attacks could demonstrate obstruction and consequent hydronephrosis, whereas imaging findings during the episode intervals were normal [28]. Bockholt et al. reported four children with UPJO who were initially diagnosed as CVS or AM because of cyclic nausea and vomiting presentation. They named UPJO “An Overlooked Cause of Cyclic Vomiting” [11]. Another investigation was performed by Kelalis et al. on 109 pediatric patients with UPJO. They found that the UPJO could mimic gastrointestinal disease in most pediatric patients with symptoms of abdominal pain and vomiting, which leads to delayed diagnosis. They reported that the average time between the symptom's onset and the diagnosis was 2.5 years. The concurrent underlying anomalies, like HSK, were detected in four patients [26].

In younger children, the pain may be felt in the periumbilical or epigastric areas rather than in the flank. The colicky nature of the pain may be accompanied by gastrointestinal symptoms due to reflex stimulation of the celiac ganglion and adjacent intraperitoneal organs [8]. Renal intake and resistance affect the presentation of a patient. Diagnostic tests during low intake may show normal results, whereas a high intake may cause an attack. Generally, in such a situation, the main focus may be to provide enough time for the attack to subside before starting any investigations. However, clinicians must be aware that sometimes, when the pain subsides, the conductor may also disappear [21].

While earlier reports suggest diuretic‐enhanced urography as the modality of choice in patients with non‐specific symptoms to detect an intermittent obstruction in the upper urinary tract, more recent ones have administered US, computed tomography (CT) scan, MRU, and renal scan [24, 25, 26]. For instance, intravenous administration of furosemide (1 mg/kg, max. 20 mg) 15 min before contrast injection for MRU has demonstrated the gradual exacerbation of hydronephrosis in real‐time; hence, it can confirm the diagnosis of UPJO after a suggestive ultrasound performed in the acute abdominal pain episode of the Dietl's crisis [7]. Some other studies used a CT scan of the abdomen and pelvis with and without contrast to clarify the diagnosis, again after an ultrasound conducted in the episode of abdominal pain [21, 22, 23]. ^99mTc‐Diethylene triamine penta‐acetic acid (^99mTc‐DTPA) diuretic renal scan can also confirm the diagnosis by showing an obstructive pattern and assessing the differential renal function (DRF) [2, 8]. The diuretic‐enhanced US can be a proper substitute in selecting surgical cases by assessing APD and parenchymal assessment. It is a non‐invasive, accessible, and repeatable imaging modality that does not involve contrast media exposure or ionizing radiation and is applicable in evaluating other organs to exclude other causes of abdominal pain [8]. In the presented case, considering the multiple hospitalizations and various diagnostic protocols, we preferred this non‐invasive provocative method. The result indicated an increase in the APD of the left renal pelvis from 24 to 43 mm after obtaining furosemide, confirming the diagnosis of intermittent UPJO for the patient.

Early diagnosis of intermittent UPJO can lead to effective management. However, selecting the optimal diagnostic modality and risk stratification markers can be challenging. A combination of diagnostic imaging, serum markers of renal function, and consideration of certain clinical complications like UTIs or urolithiasis would determine the conservative or surgical therapeutic approach to the UPJO [31]. Some DRF‐predicting factors have been introduced, yet clinical correlation confirmation is still needed. For example, the duration of each Dietl's crisis episode and the amount of APD dilation during each crisis have been reported to correlate with a DRF of less than 40% [10]. Currently, there is a trend towards non‐surgical management, especially in patients younger than 1 year old or patients with a differential renal function (DRF) of more than 40%. The rate of secondary surgical intervention in patients who were initially reported to be eligible for non‐surgical conservative management has been reported to be as high as 28% [32].

In conclusion, intermittent UPJO is a curable renal condition that can precisely mimic the symptoms of AM or CVS. The resulting hydronephrosis due to obstruction can subside between episodes. Other urologic symptoms like hematuria and UTIs might also be absent in most cases. In such situations, administrating an adequate imaging modality during an attack episode can differentiate the condition from other potential diagnoses. Provocative imaging, that is, using diuretic enhanced US, MRU, or renal scan in the asymptomatic intervals, can also initiate hydronephrosis and confirm the diagnosis. Therefore, it is recommended to ensure urological diagnostic tests are performed during the pain episodes before confirming a diagnosis of AM or CVS for any patient.

Author Contributions

Yasaman Daryabari: investigation, writing – original draft, writing – review and editing. Parmida Sadat Pezeshki: investigation, writing – original draft, writing – review and editing. Negar Mohammadi Ganjaroudi: data curation, resources, writing – original draft, writing – review and editing. Abdol‐Mohammad Kajbafzadeh: conceptualization, investigation, methodology, project administration, supervision, validation.

Consent

Written consent was obtained by the authors from the patient's legal guardian prior to submission.

Conflicts of Interest

The authors declare no conflicts of interest.

Daryabari Y., Pezeshki P. S., Mohammadi Ganjaroudi N., and Kajbafzadeh A.‐M., “Intermittent Ureteropelvic Junction Obstruction Can Mimic Abdominal Migraine: A Case Report and Review of the Literature,” Clinical Case Reports 13, no. 7 (2025): e70576, 10.1002/ccr3.70576.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.