Journal of Perinatology (2014) 34, 726–728 © 2014 Nature America, Inc. All rights reserved 0743-8346/14 www.nature.com/jp
IMAGING CASE REPORT
Congenital anterior urethral valves: imaging diagnosis and management SG Farmakis, TE Herman and MJ Siegel
Journal of Perinatology (2014) 34, 726–728; doi:10.1038/jp.2014.84
CASE PRESENTATION Case 1 A 11-day-old male term infant of an uncomplicated pregnancy presented with fever initially thought to be secondary to an upper respiratory infection. Chest radiographs were normal. A renal ultrasound was performed for suspicion of a febrile urinary tract infection (UTI), although the urinalysis and urine cultures were eventually negative. It showed mild left pelvicaliectasis with thickened urothelium concerning for an ascending UTI and pyelonephritis. Minimal pelviectasis was seen on the right. A voiding cystourethrogram (VCUG) was performed at 17 days of life and demonstrated right grade 4 vesicoureteral reflux (VUR) and grade 1 left VUR. The bladder was mildly trabeculated. Minimal narrowing was seen in the midportion of the bulbous urethra. The proximal urethra was moderately dilated (Figure 1a). Endoscopy confirmed three prominent folds of urethral mucosa representing anterior urethral valves (AUVs) either in the bulbar urethra or just proximal to it. Two folds were incised (Figures 1b and c). The third fold was left alone as the urethral lumen appeared patent and the
urinary stream was normal. The subsequent VCUG showed minimal improvement in the bulbous urethral narrowing. The right VUR had resolved. The grade 4 left VUR was unchanged; however, there was now a large diverticulum at the ureterovesicular junction (UVJ) into which the left ureter inserted. Case 2 A 6-month-old male with 1 month history of fever and failure to thrive was found to have acute renal failure. His parents reported a dribbling urinary stream. A catheter was placed, and he was started on intravenous antibiotics for a UTI. A renal ultrasound revealed severe bilateral pelvicaliectasis and ureterectasis with echogenic renal parenchyma. A 2.5 cm size discrepancy was seen in the kidneys with the right kidney being larger. The bladder wall was also thickened. Findings were suggestive of a posterior urethral valve (PUV). A VCUG demonstrated grade 5 VUR on the right, which failed to clear after bladder emptying, suggesting a UVJ obstruction as a result of the very thickened heavily trabeculated bladder wall. The bladder was very small. Thickened posterior urethral valves were suggested as the posterior urethra appeared dilated. In addition, an AUV and diverticulum were seen in the anterior urethra as represented by a focal outpouching in the bulbous urethra with a caliber change in the urethra distal to the diverticulum (Figure 2a). He underwent endoscopy and was
Figure 1. (a) Oblique projection from the initial voiding cystourethrogram shows an abrubt area of narrowing in the bulbous urethra representing the anterior urethral valve. Grade 4 vesicoureteral reflux is partially visible on the left. (b) Endoscopic photos from the cystourethroscopy demonstrate the large valve on the left side of the picture with small caliber proximal urethra looking up into the bladder (black area). (c) Post-ablation endoscopic photo. Photographs courtesy of Erica Traxel, MD.
Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA. Correspondence: Dr SG Farmakis, Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Blvd., St Louis, MO 63110, USA. E-mail: [email protected] Received 5 March 2014; revised 18 March 2014; accepted 27 March 2014
Congenital anterior urethral valves SG Farmakis et al
727 confirmed with a dilated prostatic urethra; however, although some small folds emanating from the verumontanum were incised, no posterior valvular tissue was seen. A urethral diverticulectomy was then performed through a ventral midline incision. Within the diverticulum was a large slit-like opening, which represented the anterior valvular tissue (Figure 2b). The AUV as well as the diverticulum were excised, and a urethroplasty was performed. No repeat VCUG was performed.
Figure 2. (a) The dilated posterior urethra with linear lucent band (black arrow) gave the appearance of a posterior urethra valve, although this was not confirmed at surgery. A diverticulum is seen arising from the anterior urethra. The urethra proximal to this is slightly dilated compared with the caliber of the distal urethra, indicating the presence of an anterior urethral valve with the diverticulum (white arrow). (b) Intraoperative images demonstrate the open diverticulum during the diverticulectomy. The anterior valvular tissue was incised (central slit-like opening). Photograph courtesy of Douglas Coplen, MD.
© 2014 Nature America, Inc.
DISCUSSION AUVs are a rare cause of obstructive uropathy in children and are seven times less frequent than the more commonly known entity of PUV.1 PUVs account for the majority of lower urinary tract obstructions in children. However, because AUVs are so rare, their detection is more commonly missed as a cause of lower urinary tract obstruction, which can result in renal failure. VCUG remains the gold standard in diagnosing AUV. The presentation of AUVs is variable and depends on the degree of obstruction and age of the patient.2 It can be a delayed diagnosis, and may even present as late as adulthood.3 Dribbling of urine, poor urinary stream, and UTI or urosepsis are the more common features at presentation. Rarely, a penile mass may be associated, which represents the dilated proximal urethra or diverticulum. VCUG remains the imaging gold standard in diagnosing AUV, although longitudinal transpenile ultrasound has been used to identify the valve tissue.4 An AUV represents a fold in the urethral mucosa and is typically located along the ventral surface. Obstruction results as the valve or fold rises and flattens against the dorsal surface of the urethra during micturition.5 Most valves have a semilunar appearance on endoscopy (70%), while the remaining 30% can resemble an iris.5 The location of the AUV also varies. The most common location is in the bulbar urethra, which accounts for 40%. Thirty percent occur in both the penile urethra and penoscrotal junction.1 The etiology of these valves is unknown, although several theories are present in the literature. These include a failed alignment of the glanular and penile urethra, an attempt at urethral duplication that was aborted, incomplete hypospadias, an imbalance in tissue growth in the developing urethra that results in a valve-like tissue remnant, or as a result of intrauterine obstruction.2,5,6 The diverticulum can arise either as a result of incomplete fusion of a portion of the urethral plate or failure of the corpus spongiosum to develop completely.5 As these two entities are commonly seen together (one-third), it is unclear whether the primary lesion is the valve or the diverticulum.5,7 The most commonly used classification system was described by Firlit et al.1 in 1978 and divides the AUV into four types depending on the degree of obstruction as seen on VCUG.1 In Type I, there is minimal proximal urethral distension without involvement of the bladder or upper urinary tract. In Type II, there is increased urethral distention and an associated urethral diverticulum. The bladder and upper urinary tract are not involved. In Type III, mild bladder trabeculation and ureteral ectasia with low-grade VUR are seen in addition to those findings in Type II. In Type IV, the proximal urethral dilatation is severe, a urethral diverticulum is present, the bladder trabeculation is severe, and there is high-grade VUR and marked hydroureteronephrosis.1,2,6 Only our second case fits into Firlit’s classification system (Type IV). Our first case had high-grade VUR and bladder changes without a diverticulum. The methods of treatment for AUV vary depending on the presence of a diverticulum and on other anomalies. The treatment of choice for an isolated AUV is endoscopic valve ablation.8 In the presence of a small diverticulum with adequate spongiosum, transurethral resection is the favored treatment method. If there is a large diverticulum with no supportive adjacent tissues, open diverticulectomy with primary repair is favored.5 Complications of Journal of Perinatology (2014), 726 – 728
Congenital anterior urethral valves SG Farmakis et al
728 endoscopic valve ablation include persistent proximal urethral dilatation and stricture.5 The complications of open repair include urinary extravasation, stricture and urethrocutaneous fistula formation.8 If treatment is not feasible, exteriorization of the urethra can be performed proximal to the valve. If adequate decompression is not achieved by this method, it may become necessary to perform a vesicostomy. This is especially true in newborns with associated anomalies in the genitourinary tract that may have complications, such as infection. In summary, AUVs should be considered as a cause of lower urinary tract obstruction in children presenting with UTIs, diminished urinary stream or obstructive symptoms. VCUG is a simple radiologic exam and is critical in the diagnosis of AUV. If undiagnosed, these patients may go on to develop renal failure. Most of these valves can be successfully treated by endoscopic ablation or resection. CONFLICT OF INTEREST The authors declare no conflict of interest.
Journal of Perinatology (2014), 726 – 728
REFERENCES 1 Firlit RS, Firlit CF, King LP. Obstructing anterior urethral valves in children. J Urol 1978; 119: 819–822. 2 Kajbafzadeh A, Payabvash S, Karimian G. Urodynamic changes in patients with anterior urethral valves: before and after endoscopic valve ablation. J Pediatr Urol 2007; 3: 295–300. 3 Khim A, Harris RD, Raffel J. Anterior urethral valve presenting in an adult male. Urol Radiol 1991; 12: 196–198. 4 Bates DG, Coley BD. Ultrasound diagnosis of the anterior urethral valve. Pediatr Radiol 2001; 31: 634–636. 5 Prakash J, Dalela D, Goel A, Singh V, Kumar M, Garg M et al. Congenital anterior urethral valve with or without diverticulum: a single-centre experience. J Pediatr Urol 2013; 9: 1183–1187. 6 Routh JC, McGee SM, Ashley RA, Reinberg Y, Vandersteen DR. Predicting renal outcomes in children with anterior urethral valves: a systematic review. J Urol 2010; 184: 1615–1619. 7 Kajiwara M, Inoue K, Kato M, Usui A, Matsubara A, Usui T. Anterior urethral valves in children: a possible association between anterior urethral valves and cowper’s duct cyst. Int J Urol 2007; 14: 156–160. 8 Kibar Y, Coban H, Irkilata HC, Erdemir F, Seckin B, Dayanc M. Anterior urethral valves: an uncommon cause of obstructive uropathy in children. J Pediatr Urol 2007; 3: 350–353.
© 2014 Nature America, Inc.
IMAGING CASE REPORT
Congenital anterior urethral valves: imaging diagnosis and management SG Farmakis, TE Herman and MJ Siegel
Journal of Perinatology (2014) 34, 726–728; doi:10.1038/jp.2014.84
CASE PRESENTATION Case 1 A 11-day-old male term infant of an uncomplicated pregnancy presented with fever initially thought to be secondary to an upper respiratory infection. Chest radiographs were normal. A renal ultrasound was performed for suspicion of a febrile urinary tract infection (UTI), although the urinalysis and urine cultures were eventually negative. It showed mild left pelvicaliectasis with thickened urothelium concerning for an ascending UTI and pyelonephritis. Minimal pelviectasis was seen on the right. A voiding cystourethrogram (VCUG) was performed at 17 days of life and demonstrated right grade 4 vesicoureteral reflux (VUR) and grade 1 left VUR. The bladder was mildly trabeculated. Minimal narrowing was seen in the midportion of the bulbous urethra. The proximal urethra was moderately dilated (Figure 1a). Endoscopy confirmed three prominent folds of urethral mucosa representing anterior urethral valves (AUVs) either in the bulbar urethra or just proximal to it. Two folds were incised (Figures 1b and c). The third fold was left alone as the urethral lumen appeared patent and the
urinary stream was normal. The subsequent VCUG showed minimal improvement in the bulbous urethral narrowing. The right VUR had resolved. The grade 4 left VUR was unchanged; however, there was now a large diverticulum at the ureterovesicular junction (UVJ) into which the left ureter inserted. Case 2 A 6-month-old male with 1 month history of fever and failure to thrive was found to have acute renal failure. His parents reported a dribbling urinary stream. A catheter was placed, and he was started on intravenous antibiotics for a UTI. A renal ultrasound revealed severe bilateral pelvicaliectasis and ureterectasis with echogenic renal parenchyma. A 2.5 cm size discrepancy was seen in the kidneys with the right kidney being larger. The bladder wall was also thickened. Findings were suggestive of a posterior urethral valve (PUV). A VCUG demonstrated grade 5 VUR on the right, which failed to clear after bladder emptying, suggesting a UVJ obstruction as a result of the very thickened heavily trabeculated bladder wall. The bladder was very small. Thickened posterior urethral valves were suggested as the posterior urethra appeared dilated. In addition, an AUV and diverticulum were seen in the anterior urethra as represented by a focal outpouching in the bulbous urethra with a caliber change in the urethra distal to the diverticulum (Figure 2a). He underwent endoscopy and was
Figure 1. (a) Oblique projection from the initial voiding cystourethrogram shows an abrubt area of narrowing in the bulbous urethra representing the anterior urethral valve. Grade 4 vesicoureteral reflux is partially visible on the left. (b) Endoscopic photos from the cystourethroscopy demonstrate the large valve on the left side of the picture with small caliber proximal urethra looking up into the bladder (black area). (c) Post-ablation endoscopic photo. Photographs courtesy of Erica Traxel, MD.
Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA. Correspondence: Dr SG Farmakis, Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Blvd., St Louis, MO 63110, USA. E-mail: [email protected] Received 5 March 2014; revised 18 March 2014; accepted 27 March 2014
Congenital anterior urethral valves SG Farmakis et al
727 confirmed with a dilated prostatic urethra; however, although some small folds emanating from the verumontanum were incised, no posterior valvular tissue was seen. A urethral diverticulectomy was then performed through a ventral midline incision. Within the diverticulum was a large slit-like opening, which represented the anterior valvular tissue (Figure 2b). The AUV as well as the diverticulum were excised, and a urethroplasty was performed. No repeat VCUG was performed.
Figure 2. (a) The dilated posterior urethra with linear lucent band (black arrow) gave the appearance of a posterior urethra valve, although this was not confirmed at surgery. A diverticulum is seen arising from the anterior urethra. The urethra proximal to this is slightly dilated compared with the caliber of the distal urethra, indicating the presence of an anterior urethral valve with the diverticulum (white arrow). (b) Intraoperative images demonstrate the open diverticulum during the diverticulectomy. The anterior valvular tissue was incised (central slit-like opening). Photograph courtesy of Douglas Coplen, MD.
© 2014 Nature America, Inc.
DISCUSSION AUVs are a rare cause of obstructive uropathy in children and are seven times less frequent than the more commonly known entity of PUV.1 PUVs account for the majority of lower urinary tract obstructions in children. However, because AUVs are so rare, their detection is more commonly missed as a cause of lower urinary tract obstruction, which can result in renal failure. VCUG remains the gold standard in diagnosing AUV. The presentation of AUVs is variable and depends on the degree of obstruction and age of the patient.2 It can be a delayed diagnosis, and may even present as late as adulthood.3 Dribbling of urine, poor urinary stream, and UTI or urosepsis are the more common features at presentation. Rarely, a penile mass may be associated, which represents the dilated proximal urethra or diverticulum. VCUG remains the imaging gold standard in diagnosing AUV, although longitudinal transpenile ultrasound has been used to identify the valve tissue.4 An AUV represents a fold in the urethral mucosa and is typically located along the ventral surface. Obstruction results as the valve or fold rises and flattens against the dorsal surface of the urethra during micturition.5 Most valves have a semilunar appearance on endoscopy (70%), while the remaining 30% can resemble an iris.5 The location of the AUV also varies. The most common location is in the bulbar urethra, which accounts for 40%. Thirty percent occur in both the penile urethra and penoscrotal junction.1 The etiology of these valves is unknown, although several theories are present in the literature. These include a failed alignment of the glanular and penile urethra, an attempt at urethral duplication that was aborted, incomplete hypospadias, an imbalance in tissue growth in the developing urethra that results in a valve-like tissue remnant, or as a result of intrauterine obstruction.2,5,6 The diverticulum can arise either as a result of incomplete fusion of a portion of the urethral plate or failure of the corpus spongiosum to develop completely.5 As these two entities are commonly seen together (one-third), it is unclear whether the primary lesion is the valve or the diverticulum.5,7 The most commonly used classification system was described by Firlit et al.1 in 1978 and divides the AUV into four types depending on the degree of obstruction as seen on VCUG.1 In Type I, there is minimal proximal urethral distension without involvement of the bladder or upper urinary tract. In Type II, there is increased urethral distention and an associated urethral diverticulum. The bladder and upper urinary tract are not involved. In Type III, mild bladder trabeculation and ureteral ectasia with low-grade VUR are seen in addition to those findings in Type II. In Type IV, the proximal urethral dilatation is severe, a urethral diverticulum is present, the bladder trabeculation is severe, and there is high-grade VUR and marked hydroureteronephrosis.1,2,6 Only our second case fits into Firlit’s classification system (Type IV). Our first case had high-grade VUR and bladder changes without a diverticulum. The methods of treatment for AUV vary depending on the presence of a diverticulum and on other anomalies. The treatment of choice for an isolated AUV is endoscopic valve ablation.8 In the presence of a small diverticulum with adequate spongiosum, transurethral resection is the favored treatment method. If there is a large diverticulum with no supportive adjacent tissues, open diverticulectomy with primary repair is favored.5 Complications of Journal of Perinatology (2014), 726 – 728
Congenital anterior urethral valves SG Farmakis et al
728 endoscopic valve ablation include persistent proximal urethral dilatation and stricture.5 The complications of open repair include urinary extravasation, stricture and urethrocutaneous fistula formation.8 If treatment is not feasible, exteriorization of the urethra can be performed proximal to the valve. If adequate decompression is not achieved by this method, it may become necessary to perform a vesicostomy. This is especially true in newborns with associated anomalies in the genitourinary tract that may have complications, such as infection. In summary, AUVs should be considered as a cause of lower urinary tract obstruction in children presenting with UTIs, diminished urinary stream or obstructive symptoms. VCUG is a simple radiologic exam and is critical in the diagnosis of AUV. If undiagnosed, these patients may go on to develop renal failure. Most of these valves can be successfully treated by endoscopic ablation or resection. CONFLICT OF INTEREST The authors declare no conflict of interest.
Journal of Perinatology (2014), 726 – 728
REFERENCES 1 Firlit RS, Firlit CF, King LP. Obstructing anterior urethral valves in children. J Urol 1978; 119: 819–822. 2 Kajbafzadeh A, Payabvash S, Karimian G. Urodynamic changes in patients with anterior urethral valves: before and after endoscopic valve ablation. J Pediatr Urol 2007; 3: 295–300. 3 Khim A, Harris RD, Raffel J. Anterior urethral valve presenting in an adult male. Urol Radiol 1991; 12: 196–198. 4 Bates DG, Coley BD. Ultrasound diagnosis of the anterior urethral valve. Pediatr Radiol 2001; 31: 634–636. 5 Prakash J, Dalela D, Goel A, Singh V, Kumar M, Garg M et al. Congenital anterior urethral valve with or without diverticulum: a single-centre experience. J Pediatr Urol 2013; 9: 1183–1187. 6 Routh JC, McGee SM, Ashley RA, Reinberg Y, Vandersteen DR. Predicting renal outcomes in children with anterior urethral valves: a systematic review. J Urol 2010; 184: 1615–1619. 7 Kajiwara M, Inoue K, Kato M, Usui A, Matsubara A, Usui T. Anterior urethral valves in children: a possible association between anterior urethral valves and cowper’s duct cyst. Int J Urol 2007; 14: 156–160. 8 Kibar Y, Coban H, Irkilata HC, Erdemir F, Seckin B, Dayanc M. Anterior urethral valves: an uncommon cause of obstructive uropathy in children. J Pediatr Urol 2007; 3: 350–353.
© 2014 Nature America, Inc.
