CASE 12311 Published on 12.01.2015

Pre and postoperative ultrasonographic imaging of primary non-refluxing megaureter

Section

Paediatric radiology

Case Type

Clinical Cases

Authors

Rafailidis Vasileios, Avramidis George, Patoulias Ioannis, Rafailidis Dimitrios

Radiology Department and 1st Pediatric Surgery Clinic of A.U.Th. «Gennimatas» Hospital Thessaloniki, Greece.
Email:billraf@hotmail.com
Patient

5 years, male

Categories
Area of Interest Kidney, Urinary Tract / Bladder ; Imaging Technique Ultrasound, Ultrasound-Power Doppler, Image manipulation / Reconstruction
Clinical History
A 5-year-old boy presented to the Emergency Department with colicky abdominal pain and anorexia. There was no history of congenital hydronephrosis. Laboratory exams were unremarkable except for microscopic haematuria.
Imaging Findings
The boy underwent ultrasound of the abdomen which revealed unilateral dilatation of the left pelvicalyceal system and ureter. The ureter’s diameter was 1.6 cm whereas the anteroposterior diameter of the ipsilateral pelvis was 2.7 cm. The thickness of the left renal cortex measured 1.4 cm. However, the ureteral orifice and the submucosal tunnel were normal (Fig 1, 2). A voiding cystourethrography (VCUG) was performed and excluded reflux (not presented). The patient was treated surgically. On the 5th postoperative day, a follow-up ultrasound was performed. The anteroposterior diameter of the renal pelvis was reduced to 0.8 cm and the ureter measured 1.2-1.4 cm in diameter. The repaired part of the ureter was imaged as a tubular hypoechogenic structure measuring 2.3-3.1 cm in length and 1 cm in thickness. (Fig 3)
Discussion
The term megaureter refers to a ureter larger than 7 mm in diameter which may be accompanied by dilated pelvicalyceal system. This definition applies to children aged 0 to 16 years [1, 2]. Megaureter can be primary or secondary and may be associated with reflux (refluxing or nonrefluxing) or obstruction (obstructed or nonobstructed). The term primary megaureter refers to the congenital presence of an alteration near the vesicoureteral junction [2, 3]. Primary megaureter affects boys more frequently. Secondary megaureter can be caused by pathology of the bladder or urethra (e.g. urethral valves or ureteroceles) [2, 4]. In general, dilatation of a part of the urinary tract is found in 1.5% of all neonates [5].
Primary megaureter is usually diagnosed with prenatal ultrasound. However, despite the widespread use of prenatal ultrasound, congenital malformations may also be diagnosed in adults [6, 7]. Children with postnatally diagnosed megaureter usually present with febrile urinary tract infection, abdominal pain, haematuria, urolithiasis and in some cases palpable mass [8, 9].
In patients with obstructed primary megaureter, ultrasound reveals a dilated ureter in combination with a short (0.5-4 cm) obstructive part of the ureter located just before the bladder, which is aperistaltic and normal in diameter. The dilation is more prominent in the prestenotic part of the ureter, compared to the proximal part and the ipsilateral pelvicalyceal system. The ureteral orifice and the submucosal tunnel appear normal [2]. Active peristalsis can be visible in the dilated part of the ureter. Voiding cystourethrography (VCUG) should be performed to exclude the presence of reflux or other pathology like posterior urethral valves. MAG 3 renogram easily identifies the functional obstruction of a megaureter and demonstrates the need for treatment. MRI can also demonstrate megaureter but is not suggested for routine use [2, 10].
Primary megaureter can be treated conservatively with antibiotic prophylaxis during the first year of life. Surgical treatment is indicated when there are symptoms not relieved by conservative treatment, massive hydroureteronephrosis or decreased renal function. Patients who are conservatively treated should be followed-up in the long term [10]. Ultrasound is the primary modality to examine the progressive resolution of hydronephrosis postoperatively. The latter is detectable on ultrasound for an average of 6.8 weeks in the majority of cases [11]. In our case, postoperative ultrasound showed the plicated part of the ureter accurately. Postoperative VCUG may detect reflux in 7% of patients. The younger the patient at the time of surgery and the male sex were more likely to result in improvement of resolution of hydronephrosis [12].
Differential Diagnosis List
Primary obstructed megaureter
Vesicoureteric reflux disease
Primary obstructed megaureter
Secondary megaureter due to posterior urethral valves
Secondary megaureter due to ureteral diverticulum
Final Diagnosis
Primary obstructed megaureter
Case information
URL: https://www.eurorad.org/case/12311
DOI: 10.1594/EURORAD/CASE.12311
ISSN: 1563-4086