Journal of Perinatology (2014) 34, 647–648 & 2014 Nature America, Inc. All rights reserved 0743-8346/14 www.nature.com/jp
IMAGING CASE REPORT
Neonatal presentation of posterior urethral valves and tethered spinal cord SG Farmakis, TE Herman and MJ Siegel
Journal of Perinatology (2014) 34, 647–648; doi:10.1038/jp.2014.10
CASE An 8-day-old term male infant born via cesarean section for breech presentation after an uneventful full-term pregnancy was brought to an outside hospital after several days of diarrhea and the development of puffy hands and feet. Evaluation there demonstrated low serum sodium, 102 mmol l 1 (normal 135– 146), elevated plasma potassium, 8.2 mmol l 1 (normal 3.5–5.1) and elevated creatinine 4.0 mg dl 1 (normal 0.1–0.6). Initial radiographs obtained following stabilization and placement of umbilical artery and venous catheters demonstrated minor
vertebral body segmentation anomalies of the T4 and S5 vertebral bodies. A renal sonogram (Figure 1) was performed immediately and a voiding cystourethrogram (VCUG) (Figure 2) was performed 2 days later. Because of the segmentation anomalies, a spine sonogram (Figure 3a) and spinal magnetic resonance imaging (MRI; Figure 3b) were performed.
DISCUSSION The renal ultrasound demonstrated moderate bilateral hydroureteronephrosis, echogenic renal cortices relative to the hepatic and splenic parenchyma and a thickened, trabeculated urinary bladder wall with a dilated prostatic urethra (Figure 1) consistent
Figure 1. Longitudinal renal sonograms of both the kidneys (a, b). Moderate bilateral hydronephrosis is seen. The echogenicity of both the kidneys is increased. (c) Distended urinary bladder (B), thickened and irregular bladder wall, a dilated posterior urethra (P). Mallinckrodt Institute of Radiology, St Louis Children’s Hospital, Washington University School of Medicine, St Louis, MO, USA. Correspondence: Dr TE Herman, Mallinckrodt Institute of Radiology, St. Louis Children’s Hospital, Washington University School of Medicine, 510 South Kingshighway Boulevard, St Louis, MO 63110, USA. E-mail: [email protected] Received 25 November 2013; accepted 23 December 2013
Posterior urethral valves and tethered spinal cord SG Farmakis et al
648
Figure 2. Voiding cystourethrogram image shows the markedly trabeculated bladder and dilated prostatic urethra. The transition point between dilated and normal caliber distal urethra indicates the site of the valves (arrow).
with bladder outlet obstruction and posterior urethral valves. The subsequent VCUG confirmed a thick-walled, trabeculated urinary bladder with dilated prostatic urethra and filling of prostatic ducts, confirming posterior urethral valves (Figure 2). The spinal sonogram showed an abnormally low position of the conus medullaris at L4, consistent with a tethered cord (Figure 3a). This was confirmed by the spine MRI, which demonstrated a tethered cord with the conus of the cord at the L3–L4 and an associated filum terminale lipoma (Figure 3b). Cystourethroscopy at 12 days of life confirmed posterior urethra valves, which were ablated at day 6 of life. Subsequently, the obstructive uropathy and renal failure improved. The patient was then discharged to be followed up with neurosurgery for his tethered cord. Posterior urethral valves are the result of a thick membrane of valvular tissue that obstructs the urethra, typically the prostatic urethra. Most cases are sporadic. VCUG is the diagnostic imaging procedure of choice. The classic findings are a dilated posterior urethra, thickened bladder neck and wall. On voiding, the obliquely oriented valvular tissue may be seen just inferior to the level of the verumontanum near the junction of the membranous and prostatic urethra. In addition, vesicoureteral reflux and hydronephrosis are commonly seen.1–3 Depending on the degree of obstruction and duration of obstructive symptoms, the kidneys may be dysplastic, and the bladder or calyceal fornices may rupture resulting in urinary ascites or urinomas.4 The obstructive findings associated with posterior urethral values are not typically seen on prenatal ultrasound until after 26 weeks of gestational age. This presents a diagnostic challenge as most routine second trimester-screening ultrasounds are performed prior to 24 weeks of gestation. When the valves are seen on in utero ultrasound, treatment has been attempted usually by placement of a vesicoamniotic shunt which allows the urine to drain directly into the amniotic fluid. The results have been controversial as no demonstrable improvement in the long-term results on renal function has been proven.5 The postnatal treatment remains ablation of the valvular tissue performed during endoscopy. Severe obstruction with renal failure, as in this patient, is usually detected in neonates. Patients with milder obstruction usually present after the neonatal period.6 Posterior urethral valves are uncommonly associated with other malformations, although there is a well-described association with Down’s syndrome.7 Tethered spinal cord is unusual with posterior urethral valves and in this patient, it is likely sporadic and is a part of the spectrum of occult spinal dysraphism. A sporadic occurrence is supported by the facts that tethered cord is rarely symptomatic in Journal of Perinatology (2014), 647 – 648
Figure 3. (a) Spinal ultrasound shows an abnormally low position of the conus medullaris (white arrow) at the level of L3–L4. T12, ¼ 12th vertebral body as reference point for counting level of the cord. (b) Sagittal T2-weighted magnetic resonance image confirms the low position of the conus (arrow) at the same level.
the neonate and is detected in neonates primarily due to cutaneous stigmata over the lower back, which are absent in this patient and urological abnormalities are uncommon before the age of 5 years.8 CONFLICT OF INTEREST The authors declare no conflict of interest.
REFERENCES 1 Bloom DA, Lebowitz RL, Bauer SB. Correlation of cystogrpahic bladder morphology and neuroanatomy in boys with posterior urethral valves. Pediatr Radiol 1997; 27: 553–556. 2 Banever GT, Moriarty KP. Posterior urethral valves in a newborn with imperforate anus: clinical presentation and management. J Pediatr Surg 2005; 40: 1332–1334. 3 Berrocal T, Lo´pez-Pereira P, Arjonilla A, Gutie´rrez J. Anomalies of the distal ureter, bladder, and urethra in children: embryologic, radiologic, and pathologic features. Radiographics 2002; 22: 1139–1164. 4 Chen CP, Shih SL, Liu FF, Jan SW, Tsai TC, Chang PY et al. In utero urinary bladder perforation, urinary ascites, and bilateral contained urinomas secondary to posterior urethral valves: clinical and imaging findings. Pediatr Radiol 1997; 27: 3–5. 5 Salam MA. Posterior urethral valve: outcome of antenatal intervention. Int J Urol 2006; 10: 1317–1322. 6 Pieretti RV. The mild end of the clinical spectrum of posterior urethral valves. J Pediatr Surg 1993; 28: 701–706. 7 Kupferman JC, Steward CL, Kaskel FJ, Fine RN. Posterior urethral valves in patients with Down syndrome. Pediatric Nephrol 1996; 10: 143–146. 8 Hertzler DA, DePowell JJ, Stevenson CB, Mangano FT. Tethered cord syndrome: a review of the literature from embryology to adult presentation. Neurosurg Focus 2010; 29(1): E1.
& 2014 Nature America, Inc.
IMAGING CASE REPORT
Neonatal presentation of posterior urethral valves and tethered spinal cord SG Farmakis, TE Herman and MJ Siegel
Journal of Perinatology (2014) 34, 647–648; doi:10.1038/jp.2014.10
CASE An 8-day-old term male infant born via cesarean section for breech presentation after an uneventful full-term pregnancy was brought to an outside hospital after several days of diarrhea and the development of puffy hands and feet. Evaluation there demonstrated low serum sodium, 102 mmol l 1 (normal 135– 146), elevated plasma potassium, 8.2 mmol l 1 (normal 3.5–5.1) and elevated creatinine 4.0 mg dl 1 (normal 0.1–0.6). Initial radiographs obtained following stabilization and placement of umbilical artery and venous catheters demonstrated minor
vertebral body segmentation anomalies of the T4 and S5 vertebral bodies. A renal sonogram (Figure 1) was performed immediately and a voiding cystourethrogram (VCUG) (Figure 2) was performed 2 days later. Because of the segmentation anomalies, a spine sonogram (Figure 3a) and spinal magnetic resonance imaging (MRI; Figure 3b) were performed.
DISCUSSION The renal ultrasound demonstrated moderate bilateral hydroureteronephrosis, echogenic renal cortices relative to the hepatic and splenic parenchyma and a thickened, trabeculated urinary bladder wall with a dilated prostatic urethra (Figure 1) consistent
Figure 1. Longitudinal renal sonograms of both the kidneys (a, b). Moderate bilateral hydronephrosis is seen. The echogenicity of both the kidneys is increased. (c) Distended urinary bladder (B), thickened and irregular bladder wall, a dilated posterior urethra (P). Mallinckrodt Institute of Radiology, St Louis Children’s Hospital, Washington University School of Medicine, St Louis, MO, USA. Correspondence: Dr TE Herman, Mallinckrodt Institute of Radiology, St. Louis Children’s Hospital, Washington University School of Medicine, 510 South Kingshighway Boulevard, St Louis, MO 63110, USA. E-mail: [email protected] Received 25 November 2013; accepted 23 December 2013
Posterior urethral valves and tethered spinal cord SG Farmakis et al
648
Figure 2. Voiding cystourethrogram image shows the markedly trabeculated bladder and dilated prostatic urethra. The transition point between dilated and normal caliber distal urethra indicates the site of the valves (arrow).
with bladder outlet obstruction and posterior urethral valves. The subsequent VCUG confirmed a thick-walled, trabeculated urinary bladder with dilated prostatic urethra and filling of prostatic ducts, confirming posterior urethral valves (Figure 2). The spinal sonogram showed an abnormally low position of the conus medullaris at L4, consistent with a tethered cord (Figure 3a). This was confirmed by the spine MRI, which demonstrated a tethered cord with the conus of the cord at the L3–L4 and an associated filum terminale lipoma (Figure 3b). Cystourethroscopy at 12 days of life confirmed posterior urethra valves, which were ablated at day 6 of life. Subsequently, the obstructive uropathy and renal failure improved. The patient was then discharged to be followed up with neurosurgery for his tethered cord. Posterior urethral valves are the result of a thick membrane of valvular tissue that obstructs the urethra, typically the prostatic urethra. Most cases are sporadic. VCUG is the diagnostic imaging procedure of choice. The classic findings are a dilated posterior urethra, thickened bladder neck and wall. On voiding, the obliquely oriented valvular tissue may be seen just inferior to the level of the verumontanum near the junction of the membranous and prostatic urethra. In addition, vesicoureteral reflux and hydronephrosis are commonly seen.1–3 Depending on the degree of obstruction and duration of obstructive symptoms, the kidneys may be dysplastic, and the bladder or calyceal fornices may rupture resulting in urinary ascites or urinomas.4 The obstructive findings associated with posterior urethral values are not typically seen on prenatal ultrasound until after 26 weeks of gestational age. This presents a diagnostic challenge as most routine second trimester-screening ultrasounds are performed prior to 24 weeks of gestation. When the valves are seen on in utero ultrasound, treatment has been attempted usually by placement of a vesicoamniotic shunt which allows the urine to drain directly into the amniotic fluid. The results have been controversial as no demonstrable improvement in the long-term results on renal function has been proven.5 The postnatal treatment remains ablation of the valvular tissue performed during endoscopy. Severe obstruction with renal failure, as in this patient, is usually detected in neonates. Patients with milder obstruction usually present after the neonatal period.6 Posterior urethral valves are uncommonly associated with other malformations, although there is a well-described association with Down’s syndrome.7 Tethered spinal cord is unusual with posterior urethral valves and in this patient, it is likely sporadic and is a part of the spectrum of occult spinal dysraphism. A sporadic occurrence is supported by the facts that tethered cord is rarely symptomatic in Journal of Perinatology (2014), 647 – 648
Figure 3. (a) Spinal ultrasound shows an abnormally low position of the conus medullaris (white arrow) at the level of L3–L4. T12, ¼ 12th vertebral body as reference point for counting level of the cord. (b) Sagittal T2-weighted magnetic resonance image confirms the low position of the conus (arrow) at the same level.
the neonate and is detected in neonates primarily due to cutaneous stigmata over the lower back, which are absent in this patient and urological abnormalities are uncommon before the age of 5 years.8 CONFLICT OF INTEREST The authors declare no conflict of interest.
REFERENCES 1 Bloom DA, Lebowitz RL, Bauer SB. Correlation of cystogrpahic bladder morphology and neuroanatomy in boys with posterior urethral valves. Pediatr Radiol 1997; 27: 553–556. 2 Banever GT, Moriarty KP. Posterior urethral valves in a newborn with imperforate anus: clinical presentation and management. J Pediatr Surg 2005; 40: 1332–1334. 3 Berrocal T, Lo´pez-Pereira P, Arjonilla A, Gutie´rrez J. Anomalies of the distal ureter, bladder, and urethra in children: embryologic, radiologic, and pathologic features. Radiographics 2002; 22: 1139–1164. 4 Chen CP, Shih SL, Liu FF, Jan SW, Tsai TC, Chang PY et al. In utero urinary bladder perforation, urinary ascites, and bilateral contained urinomas secondary to posterior urethral valves: clinical and imaging findings. Pediatr Radiol 1997; 27: 3–5. 5 Salam MA. Posterior urethral valve: outcome of antenatal intervention. Int J Urol 2006; 10: 1317–1322. 6 Pieretti RV. The mild end of the clinical spectrum of posterior urethral valves. J Pediatr Surg 1993; 28: 701–706. 7 Kupferman JC, Steward CL, Kaskel FJ, Fine RN. Posterior urethral valves in patients with Down syndrome. Pediatric Nephrol 1996; 10: 143–146. 8 Hertzler DA, DePowell JJ, Stevenson CB, Mangano FT. Tethered cord syndrome: a review of the literature from embryology to adult presentation. Neurosurg Focus 2010; 29(1): E1.
& 2014 Nature America, Inc.
