Hydroureteronephrosis in a male infant

Abstract

A 7-month-old boy was diagnosed with his first febrile urinary tract infection (UTI) when a catheterized urine sample revealed pyuria with significant growth of Klebsiella pneumoniae in culture. In addition, no fetal pelvicalyceal dilatation was observed. His urinary stream was also reportedly normal. Renal ultrasound done post-UTI showed bilateral hydroureteronephrosis (renal pelvis, left 23 mm; right 13 mm) and a trabeculated bladder with thickened wall of 3.3 mm. Additionally, he underwent a voiding cystourethrogram (VCUG) showing left grade V vesicoureteral reflux (VUR) and proximal dilatation of the posterior urethra (Fig. 1). Cystoscopy confirmed the diagnosis of a posterior urethral valve (PUV) which was successfully fulgurated. A dimercaptosuccinic acid radioisotope renal scan performed 3 months later showed equal cortical uptake with no photopenic defects. Infants diagnosed with UTI should undergo renal sonographic evaluation even though antenatal scans had been normal, since this could be the first occurrence of congenital structural renal abnormality. Patients found to have hydroureteronephrosis on sonography should undergo further examination with VCUG for the identification of VUR or bladder and urethral abnormalities. The presence of a dilated posterior urethra, bladder neck hypertrophy, bladder trabeculation, and secondary VUR on VCUG would strongly indicate the diagnosis of PUV.1Berrocal T. López-Pereira P. Arjonilla A. Gutiérrez J. Anomalies of the distal ureter, bladder, and urethra in children: embryologic, radiologic, and pathologic features.Radiographics. 2002; 22: 1139-1164Crossref PubMed Scopus (166) Google Scholar PUV is the most common cause of congenital bladder outlet obstruction in males, affecting 0.02% of live male births. Most cases are detected antenatally or early postnatally, with poor urinary stream or recurrent UTIs. Milder cases may also occur at a later stage in childhood with voiding difficulties.2Hodges S.J. Patel B. McLorie G. Atala A. Posterior urethral valves.ScientificWorldJournal. 2009; 9: 1119-1126Crossref PubMed Scopus (63) Google Scholar,3Lopez Pereira P. Martinez Urrutia M.J. Espinosa L. Jaureguizar E. Long-term consequences of posterior urethral valves.J Pediatr Urol. 2013; 9: 590-596Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar Importantly, PUV can lead to progressive renal disease, the pathogenesis of which includes obstructive uropathy and underlying renal dysplasia associated with abnormal nephrogenesis. Mainstay treatment of PUV is surgical relief of obstruction, usually by valve ablation; upper urinary tract diversion can also be done as a temporary measure or if urinary tract dilatation is persistent. Although surgical correction can relieve obstructive uropathy and prevent recurrent UTIs, renal dysplasia is not reversible. Since the degree of underlying renal dysplasia may lead to poor renal function, the longitudinal follow-up of all patients with PUV is important for serial monitoring of renal function, even after surgical correction.3Lopez Pereira P. Martinez Urrutia M.J. Espinosa L. Jaureguizar E. Long-term consequences of posterior urethral valves.J Pediatr Urol. 2013; 9: 590-596Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar