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Management of Antenatally Diagnosed Urological Anomalies
Review Article
MANAGEMENT OF ANTENATALLY DIAGNOSED UROLOGICAL ANOMALIES S.K. Chowdhary* and A. Kulkarni** From the: Senior Consultant, Department of Paediatric Surgery and Paediatric Urology*, Senior Consultant, Division of Neonatology**, Indraprastha Apollo Hospitals, Sarita Vihar, New Delhi 110 076, India. Correspondence to: S.K. Chowdhary, Senior Consultant, Department of Paediatric Surgery and Paediatric Urology, Indraprastha Apollo Hospitals, Sarita Vihar, New Delhi 110 076, India. The wider availability of antenatal ultrasound in the community is leading to an every increasing antenatal diagnosis of urological anomalies. The serial monitoring of the urinary tract in the affected babies in the intrauterine life provides important clue to the correct diagnosis. The antenatal management is limited to serial 4 weekly follow up, unless bilateral urinary tract is affected. Antenatal intervention remains at an experimental stage without significant documented benefit demonstrable. The most exciting area of experimental fetal urology is fetal cystoscopic ablation of posterior urethral valves. The postnatal management of these antenatally diagnosed anomalies has essentially remained unchanged. However, antenatal diagnosis does allow early accurate diagnosis and selective intervention prior to appearance of symptoms, infectious complications or further loss of renal function. Key words: Antenatal, Urological anomalies.
INTRODUCTION THE wider availability of high resolution ultrasound in our country has lead to a steadily increasing antenatal diagnosis of urological abnormalities. The effect of antenatal scanning is bound to change the face of urological practice in children in the next decade or so with earlier diagnosis and better opportunity for cure in larger number of babies. Ultrasound can detect most anomalies in a fetus, but more easily of the genitiourinary tract, because of the interface of solid and fluid. As a result, on detailed scanning at 18-20 weeks gestation, almost 20% of all anomalies detected in a fetus relate to the genitourinary tract [1]. The abnormalities detected may relate to kidneys, ureter or the bladder. Rarely, it may be possible to detect other rare anomalies in urethra, vagina etc. The incidence of detection of some urological anomaly in a fetus is about 1:500, 50% have dilated upper urinary tract of different degree [2]. However, when these babies have been followed, published data suggest only 15-40% may need surgery at some stage in life [3-4]. A brief understanding of the embryological basis of development of genitourinary abnormality is necessary to appreciate the principles of antenatal diagnosis and management. During the fifth week of gestation, the ureteral bud arising from the primitive mesonephros elongates and penetrates an area of metanephros. The site of origin of the ureteric bud and events that follow is critical to the development of a normal kidney. The junction of the Apollo Medicine, Vol. 2, No. 4, December 2005
ureteric bud stimulates the further development of kidney and urine starts flowing by the tenth week. The developing kidney, and collecting system can be identified by the eleventh week. By this time, it is possible to demonstrate gross abnormalities of the abnormal position, orientation, number, cystic malformation and dilatation of collecting system. The site for the origin of the ureteric bud, its lateral displacement, bifid terminal end, abnormal junction with metanephros and failure of the mesonephric duct to appropriately canalize may all lead to a variety of surgical abnormalities. ANTENATAL UROLOGICAL US The fetal kidney starts producing urine by the end of first trimester but it is not until 16 weeks that it significantly contributes to amniotic fluid. Any mother with reduced amniotic fluid and urinary malformation in previous sibling must have a detailed ultrasound evaluation of a urinary tract. The antenatal US should be include evaluation of kidneys, pelvic anteroposterior diameter, dilated ureter and its diameter at pelviureteric junction and vesicoureteric junction. In case of any doubt, a Doppler evaluation will clarify the ureter from vascular structures. The intermittent dilatation of pelvis and ureter needs to be recorded. By about 20 weeks the fetal bladder is seen as a round or oval fluid structure in the pelvis. Cyclical filling and emptying of the fetal bladder may be demonstrated every 40-45 minute.
378
A detailed examination done by a dedicated fetal
Review Article
medicine expert or an examination done by an obstetrician/ ultrasonologist in association with a paediatric urologist will keep in obtaining all the information necessary to lead to correct diagnosis. A fetal urological US must be reported in a standard format. The renal length, transverse pelvic diameter at the hilum, parenchymal appearance, ureteric diameter at PUJ and VUJ, intermittent or persistant ureteric dilatation through the period of examination, fetal bladder will thickness, post urethra appearance, any intraversical or urethral lesion and cyclical emptying of fetal bladder must be recorded. In case of any abnormality, serial 4 weekly US will demonstrate the progress of these lesions. ANTENTAL INTERVENTION Despite three decades of research work in fetal interventions, there is little hard data to advice any form of fetal intervention in routine clinical practice. Fetal bladder puncture and urine aspirated can be used to prognosticate disease. Vesicoamniotic shunt and fetal cystocogic ablation of post urethral valve has been reported, but remain essentially anecdotal case reports from research institutions in babies with poor prognosis. ANTENATAL DETECTION AND POSTNATAL MANAGEMENT OF UROLOGICAL ANOMALIES The first step in identifying and urological abnormality usually starts with assessment of amniotic fluid volume. Although the fetal urine starts production of urine at the end of 11 weeks, fetal urine starts contributing substantially to the amniotic fluid by the middle of mid trimester. The next consideration is whether the abnormality is unilateral or bilateral. Bilateral anomalies can have a genetic aetiology and may require extensive antenatal work up. The unilateral disease usually has an excellent prognosis. Dilatation of the upper tract may be associated with obstruction, reflux or even transient diuretic states. The cyclical emptying of the bladder and sex of the baby have to be ascertained, as male baby with obstructed bladder usually has a posterior urethral valve and a female baby have a prolapsing ureterocoele. ABSENCE OF KIDNEYS Bilateral renal agenesis occurs in about 1:4000, has a universally poor prognosis. Termination of pregnancy is the preferable option. Unilateral agenesis occurs far more commonly and merits detailed postnatal evaluation. PELVIURETERIC JUNCTION OBSTRUCTION Hydronephrosis is the commonest fetal urological abnormality. The isolated dilatation of renal collecting system merits a detailed examination of renal parenchyma,
calyces and measurement of the transvers anteroposterior (AP) diameter of the pelvis at the hilum. The severity of pelvic dilatation has been graded by society of fetal urology. Any antenatal pelvic dilatation between 6-10 mm has rarely reported to have progressed to significant postnatal disease. A pelvic AP diameter of more than 10 mm is certainly significant. If associated with calyceal dilatation, it often progresses to obstruction. Therefore, any pelvic dilatation of AP diameter greater than 10mm certainly has to be monitored at 4 weekly interval antenatally and undergo evaluation postnatally with detailed ultrasound after 48 hrs of birth, micturating cystourethrogram and isotope renogram within 4-6 weeks. The subsequent plan can be based on the findings of the above investigation after birth. The extreme degree of conservatism about management of pelviureteric junction obstruction, unless function fell below 40% in an asymptomatic baby has undergone a change [5]. Irreversible loss of function in babies with PUJ managed conservatively have been seen in long term longitudinal studies [6,7]. The fallacies of isotope renogram are better understood now. The use of prophylactic antibiotics is not evidence based, but merely an extrapolation of known practice with vesicoureteric reflux. Most centres would use prophylactic antibiotic in case of impaired drainage, for three months after birth or drainage becomes normal, whichever is earlier. An obstructed drainage curve or impaired drainage with pelvic diameter more than 3 cm, or calyceal dilatation persisting beyond one year despite a differential function of greater than 40% requires a serious evaluation for consideration for surgery. The prospective trial from Great Ormond Street hospital with conservative and operative arm is widely awaited for the final answer. Meanwhile, conservative treatment of suspected PUJ must remain a surgical decision. The onus for delayed loss of renal function during the period of conservative treatment remains the responsibility of treating unit [8]. Prior to any surgical undertaking a detailed understanding of the anatomy of the pelvis and kidney is a must. Anatomical surprises occur in less than 15% cases, but can lead to significant morbidity. Duplex related abnormality, retrocaval ureter, a very long stenotic segment, associated vesicoureteric junction obstruction or vesicoureteric reflux, ureteric valves, etc are all potential recipes for failure for surgery. Retrograde pyelogram, intravenous pyelogram and meticulouse attention to anatomical details the time of surgery lead to a greater than 90% chance of improvement in drainage after pyeloplasty [9]. Although improvement in differential function has been reported more commonly in neonates after surgery, but is
379
Apollo Medicine, Vol. 2, No. 4, December 2005
Review Article
hard to differentiate whether the improvement in differential function is due to renal growth or as a direct response of relief of obstruction. MULTICYSTIC DYSPLASTIC KIDNEY Antenatal detection of a severely hydronephrotic kidney with near total replacement of renal parenchyma with calyceal dilatation or varying size of cysts have nearly similar antenatal appearance. Multicystic dysplastic kidney (MCDK) is a developmental disease where the kidney is replaced by cysts of varying size with atretic renal vessels and ureters. It is associated with vesicouretric reflux or renal abnormalities on contralateral side in 15-20% cases [10]. There is no indication for any antenatal intervention, if the contralateral kidney is shown to be normal. Postnatally, the first effort is to distinguish it from severe PUJ, by the distribution of cysts and demonstration of renal function. In case, this is a unilateral disease it is compatible with good prognosis. Typically MCDK has the largest cyst peripherally and no function is demonstrable on DMSA SCAN. Postnatal MCU is advised to exclude, contralateral vesicoureteric reflux. This has a history of spontaneous resolution in majority. However, this may not happen with 20-25% cases. The risk of raised blood pressure is reported often enough, however reports of malignant transformation are anecdotal. Most units around the world follow a protocol of initial conservative management for 2-3 years followed by laparoscopic or open nephrectomy in cases where lesion persists. During the waiting period serial blood pressure record and US monitoring are essential. If parents chose a conservative management, they need to be advised about the risks and a life long regular follow up is essential [11,12]. VESICOURETERIC JUNCTION OBSTRUCTION The antenatal demonstration of a dilated renal pelvicalyceal system along with a dilated ureter is associated with either a refluxing ureter, refluxing obstructed ureter or obstructed ureter. The obstructed and refluxing obstructed ureter may be associated with ectopic opening of ureter. A dilated ureter can be easily confused with other tubular structures in pelvis like bowel, tubular duplication cyst or even pelvic vessels, which may require Doppler examination to differentiation and more detailed postnatal evaluation. Postnatal prophylactic antibiotic and detailed urological evaluation under antibiotic cover in presence of a represxentative from the treating unit should be done. Authors have encountered several such babies where babies Apollo Medicine, Vol. 2, No. 4, December 2005
who have required prolonged hospital stay for refractory urinary tract infection secondary to investigations done in suboptimal conditions, particularly refluxing and obstructed ureters. Vesicoureteric junction obstruction is diagnosed postnatally in a baby with megaureter, who does not have a demonstrable vesicoureteric reflux on micturating cystourethrogram. Define indication for surgery include recurrent urinary tract infection, a severe dilatation of ureter (>10 mm) and obstructed drainage pattern with a differential function of less than 40% or a deterioration after period of observation. The interpretation of the isotople renogram can be difficult, as the pooling of dye takes place in the lower end of ureter whereas often the region of interest for the computer based calculation is drawn in the renal area. If intervention is indicated, ureteric reimplantation in the infancy is not always safe. The alternative approach is a period of end ureterostomy or more recently open insertion of double J stent and observation. The stenting simulates the benefits of free drainage and allows to tide over the dangers of ureteric reimplant till infancy. Spontaneous resolution has been reported in a few babies after a period of stenting. Ureteric reimplant with or without tapering is the definitive treatment [13]. VESICOURETERIC REFLUX Hydroureteronephrosis with intermittent dilatation of ureter may be associated with antenatal diagnosis of vesicoureteric reflux (VUR). There is no role for antenatal intervention. Postnatally, fundamentally the basic aim is to investigate the possibility of primary vesicoureteric reflux versus an aetiology leading to reflux and subsequent grading of reflux. Antibiotic prophylaxis remains the mainstay of management for low grade reflux with a high chance of resolution. However, high grade of reflux or secondary vesicoureteric reflux, dysfunctional voiding, refluxing and obstructed ureter will need more detailed evaluation including urodynamic evaluation, cystoscopy with appropriate intervention [14]. POST URETHRAL VALVES Persistant dilatation of fetal bladder, failure of cyclical emptying of bladder, thickened bladder wall with or without upper tract dilatation leads to antenatal diagnosis in a male baby. During the course of antenatal 4 weekly screening, these changes have been seen to resolve spontaneously. This may be due to spontaneous antenatal rupture of valves or syringocoele in post urethra rupturing.
380
Postnatal intervention is required at the earliest. It
Review Article
should be remembered that in a small but reasonable number of babies with antenatal and postnatal diagnosis of post urethral valves, there may be functional disorder of the bladder. Video endoscopic record of the first examination of the urethra of the neonate is of fundamental importance in our circumstances for long term management. Endoscopic incision of valves after a period of successful catheter drainage of the bladder is usually the first intervention after mucturating cystourethrography. Other forms of urinary diversion are left for selected situations. Although a diversion takes care of immediate problem, often it leads to problems in the long term problems with management. Urinary undiversion and management of upper tract is deferred to after infancy and required considerable evaluation and planning [15].
3. Ouzonian JG, Castro MA, Fresquez M. Prognostic significance of antenatally detected fetal pyelectasis Ultrasound. Obstet Gynecol 1996; (76): 424-428. 4. Gruenwald SM, Cohen RC, Antico VF, Farlow DC, Cass DT. Diagnosis and treatment of antenatal fetal uropathies. J Pediatr Child Health 1990; 26(3): 142-147. 5. Koff SA, Cambell KD. The non operative management of unilateral neonatal hydronephrosis: natural history of poorly functioning kidneys. J Urol 1994: 152 (2 Pt. 2): 593595. 6. Madden NP, Thomas DF, Gordon AC. Arthur RJ, Irving HC, Smith SE. Antenatally detected pelviureteric junction obstruction: is non operation safe. Br J Urol 1991; 68(3): 305-310. 7. Subramaniam R, Kouriefs C, Dickson AP. Antenatally detected pelviureteric junction obstruction: concerns about conservative management. BJU Intl 1999; 84: 335338.
URETEROCOELE AND OTHER ANOMALIES An intravesical cystic lesion can be rarely identified either in the bladder or post urethra associated with or without abnormal fetal bladder cycling the differential diagnosis of such a lesion includes ureterocoele, syringocoele or even bladder diverticulum. In general, antenatal intervention is not required and when associated with good renal parenchyma, carry a good prognosis. Postnatal chemoprophylaxis and detailed evaluation with dye studies and endoscopy are required before any intervention can be planned. CONCLUSION Antenatal diagnosis of urological anomalies is now possible with a very high degree of precision. Unilateral anomalies are associated with usually good prognosis. Antenatal intervention has limited clinical application. Postnatal evaluation should be done by the treating unit to prevent infectious complication and need for repeating the radiological evaluations. Quantum leap in video endoscopic technology and has expanded the possibility of endoscopic surgery for majority of antenatally diagnosed urological condition. REFERENCES 1. Smith NC, Hau C. A six year study of the antenatal detection of fetal abnormality in six Scottish health boards. Br J Obstet Gynaecol 1999; 106: 206-212. 2.
Chowdhary SK, Walter S, Chaudhari RK, Bhagat A, Joseph SC. Antenatal diagnosis of hydronephrosis: outcome with a conservative approach. Ind Pediatr 2001; 38(12): 1401-1414.
8. Palmer LS, Maizels M, Cartwright PC, Fernbach SK, Conway JJ. Surgery versus observation for managing obstructive grade 3 to 4 unilateral hydronephrosis: A report from society of fetal urology. J Urol 1998; 159(1): 222-228. 9. Harish J, Joshi K, Rao KLN. Narasimahan KL, Chowdhary SK, Mahajan JK. Pelvi ureteric junction obstruction: How much should be the extent of resection of ureter with defective innervation. J Pediatr Surg 2003; 38(8): 1194-1198. 10. Wacksman J, Phipps L. Report of the multicystic Kidney Registry: preliminary findings. J Urol 1993; 150(6): 18701872. 11. Weabb NJ, Lewis MA, Bruce J, Cough DC, Ladusans EJ, Thompson AP. Unilateral multicytic dysplastic kidney: the case for nephrectomy. Arch Dis of Child 1997; 76(1): 3134. 12. Beckwith JB. Should asymptomatic unilateral multicystic dysplastic kidneys be removed because of future risk of neoplasia. Pediatr Nephrol 1992; 6(6): 551. 13. Oliviera EA, Diniz JS, Rabelo EA, et al. Primary megaureter detected by prenatal ultrasonography: Conservative management and prolonged follow up. Int Urol Nephrol 2003; 32(1): 13-18. 14. Godley ML, Desai D, Yeung CK, Dhillon GK, Duffy PG, Ransley PG. The relationship between early renal status and resolution of vesicoureteric reflux and bladder function at 16 months. BJU Int 2001; 87(6): 457-462. 15. Narasimhan KL, Kaur B, Chowdhary SK, Bhalla AK. Does mode of treatment effect the outcome of neonatal posterior urethral valves. J Urol 2004; 171: 243-246.
381
Apollo Medicine, Vol. 2, No. 4, December 2005
MANAGEMENT OF ANTENATALLY DIAGNOSED UROLOGICAL ANOMALIES S.K. Chowdhary* and A. Kulkarni** From the: Senior Consultant, Department of Paediatric Surgery and Paediatric Urology*, Senior Consultant, Division of Neonatology**, Indraprastha Apollo Hospitals, Sarita Vihar, New Delhi 110 076, India. Correspondence to: S.K. Chowdhary, Senior Consultant, Department of Paediatric Surgery and Paediatric Urology, Indraprastha Apollo Hospitals, Sarita Vihar, New Delhi 110 076, India. The wider availability of antenatal ultrasound in the community is leading to an every increasing antenatal diagnosis of urological anomalies. The serial monitoring of the urinary tract in the affected babies in the intrauterine life provides important clue to the correct diagnosis. The antenatal management is limited to serial 4 weekly follow up, unless bilateral urinary tract is affected. Antenatal intervention remains at an experimental stage without significant documented benefit demonstrable. The most exciting area of experimental fetal urology is fetal cystoscopic ablation of posterior urethral valves. The postnatal management of these antenatally diagnosed anomalies has essentially remained unchanged. However, antenatal diagnosis does allow early accurate diagnosis and selective intervention prior to appearance of symptoms, infectious complications or further loss of renal function. Key words: Antenatal, Urological anomalies.
INTRODUCTION THE wider availability of high resolution ultrasound in our country has lead to a steadily increasing antenatal diagnosis of urological abnormalities. The effect of antenatal scanning is bound to change the face of urological practice in children in the next decade or so with earlier diagnosis and better opportunity for cure in larger number of babies. Ultrasound can detect most anomalies in a fetus, but more easily of the genitiourinary tract, because of the interface of solid and fluid. As a result, on detailed scanning at 18-20 weeks gestation, almost 20% of all anomalies detected in a fetus relate to the genitourinary tract [1]. The abnormalities detected may relate to kidneys, ureter or the bladder. Rarely, it may be possible to detect other rare anomalies in urethra, vagina etc. The incidence of detection of some urological anomaly in a fetus is about 1:500, 50% have dilated upper urinary tract of different degree [2]. However, when these babies have been followed, published data suggest only 15-40% may need surgery at some stage in life [3-4]. A brief understanding of the embryological basis of development of genitourinary abnormality is necessary to appreciate the principles of antenatal diagnosis and management. During the fifth week of gestation, the ureteral bud arising from the primitive mesonephros elongates and penetrates an area of metanephros. The site of origin of the ureteric bud and events that follow is critical to the development of a normal kidney. The junction of the Apollo Medicine, Vol. 2, No. 4, December 2005
ureteric bud stimulates the further development of kidney and urine starts flowing by the tenth week. The developing kidney, and collecting system can be identified by the eleventh week. By this time, it is possible to demonstrate gross abnormalities of the abnormal position, orientation, number, cystic malformation and dilatation of collecting system. The site for the origin of the ureteric bud, its lateral displacement, bifid terminal end, abnormal junction with metanephros and failure of the mesonephric duct to appropriately canalize may all lead to a variety of surgical abnormalities. ANTENATAL UROLOGICAL US The fetal kidney starts producing urine by the end of first trimester but it is not until 16 weeks that it significantly contributes to amniotic fluid. Any mother with reduced amniotic fluid and urinary malformation in previous sibling must have a detailed ultrasound evaluation of a urinary tract. The antenatal US should be include evaluation of kidneys, pelvic anteroposterior diameter, dilated ureter and its diameter at pelviureteric junction and vesicoureteric junction. In case of any doubt, a Doppler evaluation will clarify the ureter from vascular structures. The intermittent dilatation of pelvis and ureter needs to be recorded. By about 20 weeks the fetal bladder is seen as a round or oval fluid structure in the pelvis. Cyclical filling and emptying of the fetal bladder may be demonstrated every 40-45 minute.
378
A detailed examination done by a dedicated fetal
Review Article
medicine expert or an examination done by an obstetrician/ ultrasonologist in association with a paediatric urologist will keep in obtaining all the information necessary to lead to correct diagnosis. A fetal urological US must be reported in a standard format. The renal length, transverse pelvic diameter at the hilum, parenchymal appearance, ureteric diameter at PUJ and VUJ, intermittent or persistant ureteric dilatation through the period of examination, fetal bladder will thickness, post urethra appearance, any intraversical or urethral lesion and cyclical emptying of fetal bladder must be recorded. In case of any abnormality, serial 4 weekly US will demonstrate the progress of these lesions. ANTENTAL INTERVENTION Despite three decades of research work in fetal interventions, there is little hard data to advice any form of fetal intervention in routine clinical practice. Fetal bladder puncture and urine aspirated can be used to prognosticate disease. Vesicoamniotic shunt and fetal cystocogic ablation of post urethral valve has been reported, but remain essentially anecdotal case reports from research institutions in babies with poor prognosis. ANTENATAL DETECTION AND POSTNATAL MANAGEMENT OF UROLOGICAL ANOMALIES The first step in identifying and urological abnormality usually starts with assessment of amniotic fluid volume. Although the fetal urine starts production of urine at the end of 11 weeks, fetal urine starts contributing substantially to the amniotic fluid by the middle of mid trimester. The next consideration is whether the abnormality is unilateral or bilateral. Bilateral anomalies can have a genetic aetiology and may require extensive antenatal work up. The unilateral disease usually has an excellent prognosis. Dilatation of the upper tract may be associated with obstruction, reflux or even transient diuretic states. The cyclical emptying of the bladder and sex of the baby have to be ascertained, as male baby with obstructed bladder usually has a posterior urethral valve and a female baby have a prolapsing ureterocoele. ABSENCE OF KIDNEYS Bilateral renal agenesis occurs in about 1:4000, has a universally poor prognosis. Termination of pregnancy is the preferable option. Unilateral agenesis occurs far more commonly and merits detailed postnatal evaluation. PELVIURETERIC JUNCTION OBSTRUCTION Hydronephrosis is the commonest fetal urological abnormality. The isolated dilatation of renal collecting system merits a detailed examination of renal parenchyma,
calyces and measurement of the transvers anteroposterior (AP) diameter of the pelvis at the hilum. The severity of pelvic dilatation has been graded by society of fetal urology. Any antenatal pelvic dilatation between 6-10 mm has rarely reported to have progressed to significant postnatal disease. A pelvic AP diameter of more than 10 mm is certainly significant. If associated with calyceal dilatation, it often progresses to obstruction. Therefore, any pelvic dilatation of AP diameter greater than 10mm certainly has to be monitored at 4 weekly interval antenatally and undergo evaluation postnatally with detailed ultrasound after 48 hrs of birth, micturating cystourethrogram and isotope renogram within 4-6 weeks. The subsequent plan can be based on the findings of the above investigation after birth. The extreme degree of conservatism about management of pelviureteric junction obstruction, unless function fell below 40% in an asymptomatic baby has undergone a change [5]. Irreversible loss of function in babies with PUJ managed conservatively have been seen in long term longitudinal studies [6,7]. The fallacies of isotope renogram are better understood now. The use of prophylactic antibiotics is not evidence based, but merely an extrapolation of known practice with vesicoureteric reflux. Most centres would use prophylactic antibiotic in case of impaired drainage, for three months after birth or drainage becomes normal, whichever is earlier. An obstructed drainage curve or impaired drainage with pelvic diameter more than 3 cm, or calyceal dilatation persisting beyond one year despite a differential function of greater than 40% requires a serious evaluation for consideration for surgery. The prospective trial from Great Ormond Street hospital with conservative and operative arm is widely awaited for the final answer. Meanwhile, conservative treatment of suspected PUJ must remain a surgical decision. The onus for delayed loss of renal function during the period of conservative treatment remains the responsibility of treating unit [8]. Prior to any surgical undertaking a detailed understanding of the anatomy of the pelvis and kidney is a must. Anatomical surprises occur in less than 15% cases, but can lead to significant morbidity. Duplex related abnormality, retrocaval ureter, a very long stenotic segment, associated vesicoureteric junction obstruction or vesicoureteric reflux, ureteric valves, etc are all potential recipes for failure for surgery. Retrograde pyelogram, intravenous pyelogram and meticulouse attention to anatomical details the time of surgery lead to a greater than 90% chance of improvement in drainage after pyeloplasty [9]. Although improvement in differential function has been reported more commonly in neonates after surgery, but is
379
Apollo Medicine, Vol. 2, No. 4, December 2005
Review Article
hard to differentiate whether the improvement in differential function is due to renal growth or as a direct response of relief of obstruction. MULTICYSTIC DYSPLASTIC KIDNEY Antenatal detection of a severely hydronephrotic kidney with near total replacement of renal parenchyma with calyceal dilatation or varying size of cysts have nearly similar antenatal appearance. Multicystic dysplastic kidney (MCDK) is a developmental disease where the kidney is replaced by cysts of varying size with atretic renal vessels and ureters. It is associated with vesicouretric reflux or renal abnormalities on contralateral side in 15-20% cases [10]. There is no indication for any antenatal intervention, if the contralateral kidney is shown to be normal. Postnatally, the first effort is to distinguish it from severe PUJ, by the distribution of cysts and demonstration of renal function. In case, this is a unilateral disease it is compatible with good prognosis. Typically MCDK has the largest cyst peripherally and no function is demonstrable on DMSA SCAN. Postnatal MCU is advised to exclude, contralateral vesicoureteric reflux. This has a history of spontaneous resolution in majority. However, this may not happen with 20-25% cases. The risk of raised blood pressure is reported often enough, however reports of malignant transformation are anecdotal. Most units around the world follow a protocol of initial conservative management for 2-3 years followed by laparoscopic or open nephrectomy in cases where lesion persists. During the waiting period serial blood pressure record and US monitoring are essential. If parents chose a conservative management, they need to be advised about the risks and a life long regular follow up is essential [11,12]. VESICOURETERIC JUNCTION OBSTRUCTION The antenatal demonstration of a dilated renal pelvicalyceal system along with a dilated ureter is associated with either a refluxing ureter, refluxing obstructed ureter or obstructed ureter. The obstructed and refluxing obstructed ureter may be associated with ectopic opening of ureter. A dilated ureter can be easily confused with other tubular structures in pelvis like bowel, tubular duplication cyst or even pelvic vessels, which may require Doppler examination to differentiation and more detailed postnatal evaluation. Postnatal prophylactic antibiotic and detailed urological evaluation under antibiotic cover in presence of a represxentative from the treating unit should be done. Authors have encountered several such babies where babies Apollo Medicine, Vol. 2, No. 4, December 2005
who have required prolonged hospital stay for refractory urinary tract infection secondary to investigations done in suboptimal conditions, particularly refluxing and obstructed ureters. Vesicoureteric junction obstruction is diagnosed postnatally in a baby with megaureter, who does not have a demonstrable vesicoureteric reflux on micturating cystourethrogram. Define indication for surgery include recurrent urinary tract infection, a severe dilatation of ureter (>10 mm) and obstructed drainage pattern with a differential function of less than 40% or a deterioration after period of observation. The interpretation of the isotople renogram can be difficult, as the pooling of dye takes place in the lower end of ureter whereas often the region of interest for the computer based calculation is drawn in the renal area. If intervention is indicated, ureteric reimplantation in the infancy is not always safe. The alternative approach is a period of end ureterostomy or more recently open insertion of double J stent and observation. The stenting simulates the benefits of free drainage and allows to tide over the dangers of ureteric reimplant till infancy. Spontaneous resolution has been reported in a few babies after a period of stenting. Ureteric reimplant with or without tapering is the definitive treatment [13]. VESICOURETERIC REFLUX Hydroureteronephrosis with intermittent dilatation of ureter may be associated with antenatal diagnosis of vesicoureteric reflux (VUR). There is no role for antenatal intervention. Postnatally, fundamentally the basic aim is to investigate the possibility of primary vesicoureteric reflux versus an aetiology leading to reflux and subsequent grading of reflux. Antibiotic prophylaxis remains the mainstay of management for low grade reflux with a high chance of resolution. However, high grade of reflux or secondary vesicoureteric reflux, dysfunctional voiding, refluxing and obstructed ureter will need more detailed evaluation including urodynamic evaluation, cystoscopy with appropriate intervention [14]. POST URETHRAL VALVES Persistant dilatation of fetal bladder, failure of cyclical emptying of bladder, thickened bladder wall with or without upper tract dilatation leads to antenatal diagnosis in a male baby. During the course of antenatal 4 weekly screening, these changes have been seen to resolve spontaneously. This may be due to spontaneous antenatal rupture of valves or syringocoele in post urethra rupturing.
380
Postnatal intervention is required at the earliest. It
Review Article
should be remembered that in a small but reasonable number of babies with antenatal and postnatal diagnosis of post urethral valves, there may be functional disorder of the bladder. Video endoscopic record of the first examination of the urethra of the neonate is of fundamental importance in our circumstances for long term management. Endoscopic incision of valves after a period of successful catheter drainage of the bladder is usually the first intervention after mucturating cystourethrography. Other forms of urinary diversion are left for selected situations. Although a diversion takes care of immediate problem, often it leads to problems in the long term problems with management. Urinary undiversion and management of upper tract is deferred to after infancy and required considerable evaluation and planning [15].
3. Ouzonian JG, Castro MA, Fresquez M. Prognostic significance of antenatally detected fetal pyelectasis Ultrasound. Obstet Gynecol 1996; (76): 424-428. 4. Gruenwald SM, Cohen RC, Antico VF, Farlow DC, Cass DT. Diagnosis and treatment of antenatal fetal uropathies. J Pediatr Child Health 1990; 26(3): 142-147. 5. Koff SA, Cambell KD. The non operative management of unilateral neonatal hydronephrosis: natural history of poorly functioning kidneys. J Urol 1994: 152 (2 Pt. 2): 593595. 6. Madden NP, Thomas DF, Gordon AC. Arthur RJ, Irving HC, Smith SE. Antenatally detected pelviureteric junction obstruction: is non operation safe. Br J Urol 1991; 68(3): 305-310. 7. Subramaniam R, Kouriefs C, Dickson AP. Antenatally detected pelviureteric junction obstruction: concerns about conservative management. BJU Intl 1999; 84: 335338.
URETEROCOELE AND OTHER ANOMALIES An intravesical cystic lesion can be rarely identified either in the bladder or post urethra associated with or without abnormal fetal bladder cycling the differential diagnosis of such a lesion includes ureterocoele, syringocoele or even bladder diverticulum. In general, antenatal intervention is not required and when associated with good renal parenchyma, carry a good prognosis. Postnatal chemoprophylaxis and detailed evaluation with dye studies and endoscopy are required before any intervention can be planned. CONCLUSION Antenatal diagnosis of urological anomalies is now possible with a very high degree of precision. Unilateral anomalies are associated with usually good prognosis. Antenatal intervention has limited clinical application. Postnatal evaluation should be done by the treating unit to prevent infectious complication and need for repeating the radiological evaluations. Quantum leap in video endoscopic technology and has expanded the possibility of endoscopic surgery for majority of antenatally diagnosed urological condition. REFERENCES 1. Smith NC, Hau C. A six year study of the antenatal detection of fetal abnormality in six Scottish health boards. Br J Obstet Gynaecol 1999; 106: 206-212. 2.
Chowdhary SK, Walter S, Chaudhari RK, Bhagat A, Joseph SC. Antenatal diagnosis of hydronephrosis: outcome with a conservative approach. Ind Pediatr 2001; 38(12): 1401-1414.
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Apollo Medicine, Vol. 2, No. 4, December 2005