| Abstract|| |
Multicystic renal dysplasia (MCRD) is the most common cause of abnormally enlarged kidney, diagnosed on antenatal ultrasound examination. It is an abnormality of the embryonic development in which the renal parenchyma is substituted by nonfunctioning renal tissue made up of cysts which do not communicate with each other. Vesicoureteric reflux (VUR), pelviureteric junction obstruction, vesicoureteric junction obstruction, and ureterocele are the most commonly seen abnormalities in contralateral kidney. Here, we report a case of prenatal diagnosis of unilateral MCRD with VUR in contralateral kidney. In conclusion, we want to emphasize optimal use of ultrasound imaging to detect such abnormalities as early as possible to guide the proper management.
|How to cite this article:|
Pandya VK, Sutariya HC. Unilateral multicystic renal dysplasia: Prenatal diagnosis on ultrasound. Saudi J Kidney Dis Transpl 2017;28:916-20
|How to cite this URL:|
Pandya VK, Sutariya HC. Unilateral multicystic renal dysplasia: Prenatal diagnosis on ultrasound. Saudi J Kidney Dis Transpl [serial online] 2017 [cited 2021 Apr 10];28:916-20. Available from: https://www.sjkdt.org/text.asp?2017/28/4/916/211349
| Introduction|| |
Multicystic renal dysplasia (MCRD) is the most common antenatally diagnosed cystic renal pathology. It refers to the presence of multiple renal cysts surrounded by dysplastic parenchymal tissue. Congenital renal dysplasia may be explained by an abnormal induction of metanephric blastoma by the migrating ure- teric bud. It has been suggested that displaced metanephric blastoma interspersed with normal zones of nephrogenes generates the irregular parenchyma of the multicystic kidney. The subsequent cystic dilatation of dysplastic tissue compresses and permanently damages the normal renal tissue. By definition, the affected kidney is nonfunctioning and is usually associated with an atretic ureter. Vesico- ureteric reflux (VUR) is the most commonly seen abnormality in contralateral kidney. Wide availability of antenatal ultrasound makes the prenatal diagnosis of these abnormalities easier.
| Case Report|| |
A young primi was scanned for congenital anomalies at 22 weeks of gestation. On ultrasound, single live fetus with fetal heart rate of 143 beats/min was seen. On biophysical profile, fetal movements, fetal tone, and breathing were normal, but the amniotic fluid index was inadequate. On anomaly scan, multiple cysts of variable sizes in the right paraspinous location with no normally appearing kidney parenchyma were found. The contralateral kidney showed hydronephrosis [Figure 1]a and [Figure 1]b and mild hydroureter involving small part of upper ureter. Unfortunately, whole of the ureter could not be traced due to unfavorable fetal position. The fetal bladder and rest of the fetal abdomen showed no abnormality. The probable prenatal diagnosis of fetal unilateral MCRD with contralateral VUR was made. Approximately 1.85 kg weighing male baby was delivered at full term by elective cesarean section. The baby cried soon after birth. Postnatal ultrasound confirmed the presence of MCRD on right side, and the contralateral kidney showed mild hydronephrosis with mild upper hydro-ureter [Figure 2]a and [Figure 2]b. On micturating cystourethrogram, reflux was not evident in the initial films. Surprisingly, the presence of VUR was seen in delayed films [Figure 3]a and [Figure 3]b. Ethylenedicysteine (EC) scan showed non-visualization of the right kidney and enlarged grossly hydronephrotic left kidney with preserved relative function and slow drainage [Figure 4]. As our patient was symptomatically stable, he was treated by chemoprophylaxis and is doing well. The patient is advised to follow up periodically to diagnose complications as early as possible, if any.
|Figure 1: (a) Antenatal ultrasound image showing multiple cysts with no intervening normal renal parenchyma on the right side suggesting multicystic renal dysplasia, (b) Antenatal ultrasound image showing hydronephrosis on the left side.|
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|Figure 2: (a) Postnatal ultrasound image showing multiple cysts with no intervening normal renal parenchyma on the right side confirming multicystic renal dysplasia, (b) postnatal ultrasound image showing hydronephrosis on the left side with mild upper hydroureter.|
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|Figure 3: (a) Voiding film of micturating cystourethrogram showing normal appearance of bladder and urethra with no evidence of vesicoureteric reflux, (b) delayed film of micturating cystourethrogram after micturition shows moderate hydronephrosis and dilated and tortuous ureter up to lower end suggesting vesicoureteric reflux.|
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|Figure 4: EC renal scan confirming the presence of nonexcreting kidney on the right side and hydronephrosis and hydroureter on the left side with slow drainage.|
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| Discussion|| |
The antenatal diagnosis of fetal anomalies has improved considerably due to the wide availability of high-resolution ultrasound equipment. Ultrasound imaging can demonstrate the fetal bladder shortly after the 11th week of gestation when the kidneys start production of urine, and it is possible to detect the changes of nephrogenesis which continue until 38 weeks of gestation. The proportion of renal abnormalities diagnosed by antenatal ultraound has increased from 15% in 1984 to more than 80% in the recent studies. The overall incidence of unilateral multicystic dysplastic kidney is approximately 1 in 4300 live births. Left kidney is more commonly affected in unilateral MCRD (in 53.1% cases).,,, Renal dysplasia is a form of abnormal renal parenchymal development resulting from anomalous differentiation of metanephric tissue during embryogenesis. Most of the dysplastic kidneys are associated with some form of obstruction of the urinary tract during nephrogenesis. The type and severity of renal dysplasia depends on the pattern of malformation and severity of urinary tract obstruction. Based on these criteria, renal dysplasia has been broadly subdivided into four groups: Group I - classical multicystic dysplasia resulting from ureteral atresia at pelviureteric junction (PUJ), Group II - focal and segmental cystic renal dysplasia usually caused by obstruction, related to ectopic ureterocele with ureteral duplication, Group III - cystic renal dysplasia associated with lower urinary tract obstruction, for example, posterior urethral valves, and Group IV- heredofamilial renal dysplasia without any obstructive uropathy.
MCRD is usually an incidental finding during routine antenatal ultrasonographic examination. It has two types: classical and segmental. Classical type involves the whole kidney and it is more commonly seen in males, whereas the other type affects upper pole of a duplex kidney and is more common in females with a predilection of the right kidney. It is unilateral in 76% of cases and bilateral in 24% of cases. Bilateral multicystic disease is incompatible with extrauterine life. Ultrasound shows grape-like clusters of noncommunicating cysts in enlarged kidneys, absence of urine accumulation in the bladder, and severe oligohydramnios. Measurement of anteroposterior (AP) pelvic diameter and its ratio to overall AP renal diameter have been proposed as criteria for abnormal. In fetus younger than 24 weeks, AP pelvic diameter greater than 10 mm was 76% sensitive in identifying an obstruction.
The affected kidneys may enlarge or may actually shrink in size or rarely may disappear. Contralateral kidney may show the presence of VUR, PUJ obstruction or vesicoureteric junction obstruction, and ureterocele. There may be associated nonrenal anomalies such as congenital heart defects, central nervous system anomalies, spinal malformations, gastrointestinal malformations, single umbilical artery, omphalocele, abnormal extremities, and chromosomal anomalies There is an increased risk of Wilms tumor and renal cell carcinoma development in the kidney with MCRD, in children who survive. It also profoundly affects the fetal lung development, critical transition from the canalicular to alveolar phase. Autosomal recessive polycystic kidney is a common differential diagnosis for multicystic disease of the kidney, cysts in the former are small, and parenchyma is generally hyperechoic. Other cystic diseases typically appear with some functional parenchyma. MCRD is seen as multiple cysts involving whole or part of the affected kidney with echogenic parenchyma. Corticomedullary differentiation is not preserved. Multiple cysts are noncommunicating with each other. Regarding treatment, unilateral MCRD is treated by conservative method and is followed up periodically to diagnose complications at earliest. If contralateral kidney is abnormal, it is treated accordingly. However, a newborn child with unilateral disease may need percutaneous cyst aspiration in case of compromised respiratory function, due to mass effect. Follow-up with ultrasound examination, every three months, for the 1st year of life, is recommended. Nephrectomy may be an option later on.
| Conclusion|| |
Cystic kidneys discovered incidentally during routine antenatal ultrasonography are significant diagnostic dilemma. There are diverse etiologies with equally variable implications for prognosis in the affected fetus. Correct and timely antenatal diagnosis of MCRD with associated fetal anomalies by ultrasound is important so that the proper counseling and appropriate obstetric and pediatric management can be done.
Conflict of interest: None declared.
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Vaidehi K Pandya
Department of Radio Diagnosis and Imaging, G. R. Doshi and K. M. Mehta Institute of Kidney Diseases and Research Center - Dr. H. L. Trivedi Institute of Transplantation Sciences, Civil Hospital Campus, Asarwa, Ahmedabad - 380016, Gujarat
[Figure 1], [Figure 2], [Figure 3], [Figure 4]