Thesis (MMed)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: OBJECTIVES The aim of this study was to determine long-term renal function in boys presenting with posterior urethral valves at Tygerberg Children’s Hospital and to determine the prognostic value of certain clinical, biochemical and radiological variables DESIGN Retrospective, descriptive study of boys diagnosed and treated with posterior urethral valves at Tygerberg Children’s Hospital between 2001 and 2011. RESULTS Between 2001 and 2011, 47 cases of posterior urethral valves were diagnosed and treated at our institution. Thirteen patients were excluded from this study. Seven (20,6%) were diagnosed antenatally and 27 (79,4%) presented postnatally. Mean age at presentation was 13,9 months (median 2; range 0-74). The most common postnatal presentation was urinary tract infection (51,9%). Mean follow-up was 54,2 months (median 47,5; range 12-133). A total of 13 boys (38,2%) progressed to chronic renal failure or end-stage renal disease. Initial and nadir serum creatinine, poor corticomedullary differentiation and moderate-severe hydronephrosis were significant predictors of final renal function (p<0,050). Patient age at presentation, type of primary surgical intervention, increased renal echogenicity, bladder wall thickness, the presence of vesicoureteric reflux (no matter what the laterality or severity), severe bladder dysfunction and initial or breakthrough urinary tract infection had no significant impact on future renal function. Receiver operating characteristic curve analysis confirmed that boys with an initial serum creatinine ≥145μmol/L and a nadir serum creatinine ≥62μmol/L were at highest risk to develop chronic renal insufficiency (area under the curve 0,8 and 0,9, respectively). CONCLUSION More than a third of boys (38,2%) developed chronic renal failure or end-stage renal disease at the end of follow-up. Our data confirmed the high prognostic value of initial and nadir serum creatinine. Optimal threshold levels for initial and nadir serum creatinine to predict final renal function were 145μmol/L and 62μmol/L, respectively. Similarly, poor corticomedullary differentiation and moderate-severe hydronephrosis on initial kidney ultrasound were significant indicators of poor renal prognosis. Although all patients with posterior urethral valves should be counselled on potential renal morbidity, children with risk factors warrant closer monitoring. / AFRIKAANSE OPSOMMING: DOELWITTE Die doel van hierdie studie was om langtermyn nierfunksie te bepaal in seuns wat gediagnoseer is met posterior uretrale kleppe by Tygerberg-kinderhospitaal. Die prognostiese waarde van sekere kliniese, biochemiese en radiologiese veranderlikes is ook ondersoek. STUDIE ONTWERP Retrospektiewe, beskrywende studie van seuns wat tussen 2001 en 2011 by Tygerberg-kinderhospitaal gepresenteer het met posterior uretrale kleppe. RESULTATE Tussen 2001 en 2011 is 47 gevalle van posterior uretrale kleppe gediagnoseer en behandel by ons instelling. Dertien pasiënte is uitgesluit van hierdie studie. Sewe (20,6%) is met voorgeboorte sonar gediagnoseer en 27 (79,4%) het ná geboorte gepresenteer. Die gemiddelde ouderdom by diagnose was 13,9 maande (mediaan 2; reeks 0-74 ). Urienweginfeksie was die mees algemene metode waarmee postnatale pasiënte gepresenteer het (51,9%). Die gemiddelde opvolgperiode was 54,2 maande (mediaan 47,5; reeks 12-133). Dertien seuns (38,2%) het chroniese nierversaking of eind-stadium nierversaking ontwikkel. Aanvanklike en nadir serumkreatinien, swak kortiko-medullêre differensiasie en matig-erge hidronefrose was beduidende voorspellers van finale nierfunksie (p<0,050). Pasiënt ouderdom met diagnose, tipe chirurgiese ingryping, verhoogde niereggogenisiteit, blaaswanddikte, vesikoureteriese refluks, blaasdisfunksie en aanvanklike of deurbraak urienweginfeksies het geen beduidende impak op toekomstige nierfunksie gehad nie. Seuns met 'n aanvanklike serumkreatinien ≥145μmol/L en 'n nadir serumkreatinien ≥62μmol/L het die grootste risiko om chroniese nierversaking te ontwikkel, soos bevestig met ‘n ROC-ontleding (AUC 0,8 en 0,9, onderskeidelik). GEVOLGTREKKING Meer as 'n derde van die pasiënte (38,2%) het chroniese nierversaking of eindstadium nierversaking ontwikkel. Ons data bevestig die prognostiese waarde van aanvanklike en nadir serumkreatinienvlakke. Die optimale drempelwaardes vir die aanvanklike en nadir serumkreatinien om finale nierfunksie te voorspel was 145μmol/L en 62μmol/L, onderskeidelik. Swak kortiko-medullêre differensiasie en matig-erge hidronefrose op die aanvanklike niersonar was ook beduidende aanwysers van toekomstige nierfunksie. Alhoewel alle pasiënte met posterior uretrale kleppe berading moet ontvang oor potensiële niermorbiditeit, regverdig seuns met risikofaktore noukeurige monitering.