A study of prevalence of various types of congenital malformations of urinary tract at tertiary health care center

 

Santosh Bajaj¹, Kalpana Jaju^2*

 

Abstract              Background: Congenital anomalies of the kidney and urinary tract (CAKUT) are observed in three to six per 1000 live births and account for 40–50% of the etiology of chronic kidney disease (CKD) in children worldwide. They has the potential to impact fetal lung maturity which in turn has important prognostic implications. Present study was aimed to study prevalence of various types of congenital malformations of urinary tract at tertiary health care center. Material and Methods: Present study was institution based, cross-sectional, observational study, conducted in neonates with antenatal ultrasound suggestive of an abnormality of the urinary tract, delivered at our hospital or referred from outside within 24 hours of birth. Results: During study period 68 cases were studied. Most cases were detected in third trimester (55.88 %), 30.88 % diagnosed in second trimester and 13.24 % were diagnosed after delivery. Though 30.88 % were diagnosed in second trimester, patients did not opted termination. Abnormalities of AFI (52.94 %), family history of congenital anomaly (4,41 %), were maternal risk factors noted. Hydronephrosis (30.88 %) was most common congenital malformations of urinary tract followed by polycystic kidney disease (20.59 %), pelviureteric junction obstruction (19.12 %), posterior urethral valve (17.65 %), ambiguous genitalia (4.41 %), epispadius (2.94 %), duplicated collecting system (2.94 %), hypospadias (1.47 %) and bladder exstrophy (1.47 %). In present study 42.65 % cases required observation only, while 26.47 % required surgery in neonatal period and 19.12 % were referred to higher centre for the same. Neonatal death was noted in 11.76 % cases. Conclusion: Hydronephrosis was most followed by polycystic kidney disease, pelviureteric junction obstruction, posterior urethral valve were common congenital malformations of urinary tract noted. Majority required observation only while few required surgical intervention.

Keywords: congenital malformations of urinary tract, hydronephrosis, polycystic kidney disease, pelviureteric junction obstruction,

 

INTRODUCTION

Congenital anomalies of the kidney and urinary tract (CAKUT) are observed in three to six per 1000 live births and account for 40–50% of the etiology of chronic kidney disease (CKD) in children worldwide.^1,2 Congenital renal anomalies can be sporadic or familial, syndromic (also affecting non-renal tissues) or non-syndromic.³ The primary insults believed to be associated with the development of CAKUT are environmental factors and genetic mechanisms. Various genetic loci associated with syndromic CAKUT are identified. In animal models, deletion of several of these genes results in low nephron endowment including PAX2, p53, GLI3R, GDNF, FGF 7, FRS2 and Six2.^4,5 Congenital anomalies of the kidney and urinary tract (CAKUT) comprises of a spectrum of defects involving kidney (hypoplasia and dysplasia), ureters and bladder (vesico-ureteral reflux, duplex system) and urethra (posterior urethral valves) that results from perturbations in the development of the kidney and urinary tract during fetal life. ^6,7 The malformations may affect the kidney and urinary tract unilaterally and bilaterally or may occur in syndromic forms with other organ defects.⁸ In addition, urinary tract disease has the potential to impact fetal lung maturity which in turn has important prognostic implications. An accurate diagnosis of these anomalies is therefore of paramount importance and can prove to be valuable in formulating management strategies and influencing parental counseling.⁹ Present study was aimed to study prevalence of various types of congenital malformations of urinary tract at tertiary health care center.

              

MATERIAL AND METHODS

Present study was institution based, cross-sectional, observational study, conducted in department of pediatrics in collaboration with department of obstetrics and gynecology at XXX medical college and hospital, XXX, India. Study duration was of 2 years (January 2020 to December 2021).

Inclusion criteria: Neonates with antenatal ultrasound suggestive of an abnormality of the urinary tract, delivered at our hospital or referred from outside within 24 hours of birth

Exclusion criteria: Neonates not completed 6 months follow-up

The written informed consent from the parents and approval from the institutional ethical committee was obtained. The demographic variables which included age, weight, gravida, parity and consanguinity were recorded. A detailed obstetric history of any risk factor for development of congenital renal or urinary tract anomalies like history of oligohydramnios, poor weight gain or hypertension, diabetes, obesity, increase salt intake, alcohol consumption, exposure to teratogens, etc. during pregnancy was obtained from mother’s hospital records. Antenatal Details such as Age of diagnosis, biometry and amniotic fluid, morphology of the urogenital system, diagnoses suspected by ultrasound, topographic distribution, associated extra-renal malformations and syndromic approach, outcome of pregnancy and gestational age, fetal sex, Apgar score and the Weight at birth was noted. Outcomes were assessed with any postnatal persistence of antenatally diagnosed CAKUT and persistence during the follow up period of six months, the degree and progression of CAKUT and comparison with previous scans, any surgical intervention, the findings of additional investigations such as CT scan, MRI, MCU, DMSA and DTPA scans, if done. Data was collected and compiled using Microsoft Excel, analysed using SPSS 23.0 version. Statistical analysis was done using descriptive statistics. Frequency, percentage, means and standard deviations (SD) was calculated for the continuous variables, while ratios and proportions were calculated for the categorical variables.

DISCUSSION

Major structural anomalies appear in 2-3% in live newborns and other 2-3% are discovered in children up to 5 years old, summarizing 4-6%. Minor anomalies appear in approximately 15% out of the total of newborns.¹⁰ These anomalies do not alter the individual’s health status, but they are associated with major defects in some cases, therefore they can serve as key elements for the diagnosis of more serious, hidden defects. CAKUT is a clinically heterogeneous phenotype that encompasses renal agenesis, renal hypoplasia/dysplasia, multicystic kidney dysplasia, cross-fused ectopia, duplex renal collecting system, ureteropelvic junction obstruction, mega-ureter, posterior urethral valves, and vesicoureteral reflux (VUR). High resolution ultrasonography, magnetic resonance imaging, and nuclear imaging are crucial in diagnosis and subsequent observation.¹¹ Ameen, S.K.et al.,¹² at Maternity Teaching Hospital, Erbil noted rate of congenital anomaly as 3.63/1000 deliveries. The most common area for anomalies was the central nervous system (37.7%) followed by the musculoskeletal (23.1%) and gastrointestinal systems (20.8%). There was a statistically significant association between having a child with congenital anomalies and a maternal history of previous congenital anomalies (odds ratio [OR] 59.0, 95% CI 5.74–607.0), parental consanguinity (OR 6.26, 95% CI 2.42–16.19), and history of medical disorders (OR 153.2, 95% CI 25.9–905.4). While Hekmat Chaara et al., ¹³ noted that MCDK was the most frequently diagnosed fetal abnormality (44.44%), followed by Posterior urethral valves (PUV) (22.22%), renal agenesis (13.89%), Autosomal recessive polycystic kidney disease (ARKD) (11.11%), Ureteropelvic junction (UPJ) obstruction (11.11%), duplicated collecting system (8.33%) and isolated fetal pyelectasis observed in two cases with a percentage of 5.56% with a predominance on the left side. Chougule A, et al.,¹⁴ noted that CAKUT was more common among males. Hydronephrosis was the most common CAKUT in antenatal scans. Anomalies of the renal collecting system formed 93.9% of all CAKUT detected on antenatal anomaly scan and 57.4% of these resolved by six months of age. Abnormalities of the renal collecting system together formed 93.9% of all antenatally diagnosed CAKUT and were more common than abnormalities of the renal parenchyma which formed 6.1%. Postnatal resolution on day three USG was seen in seven out of 22 (31.8%) cases of antenatally diagnosed mild hydronephrosis irrespective of their site. Out of the 28 antenatally diagnosed hydronephrosis, 11 (39.3%) resolved at some point during the follow up period of six months. Veerabhadra R et al.,¹⁶ studied 81 patients (neonates and children below 13 years of age) with CAKUT, Twenty-two (27%) patients were underweight, 4 (5%) patients were stunted, and 26 (32%) were both underweight and stunted. Children with bilateral disease had a higher incidence of underweight (21/44 vs. 8/37; p = 0.04), and both underweight and stunted (25/44 vs. 10/37; p = 0.006) compared to children with unilateral disease. Hypertension was found in 27% cases. Bilateral disease in CAKUT was significantly associated with poor somatic growth. Unilateral renal agenesis occurs in approximately 1/1,300 pregnancies, the majority of which are probably cases of renal aplasia.^17,18 The difference between both cannot be made by ultrasound. Although unilateral renal agenesis is mostly isolated and sporadic, it might be part of a genetic syndrome, or occur in association with chromosomal or developmental defects (VACTeRL association) and genital abnormalities. The etiology of antenatal hydronephrosis is very diverse and majority of cases are transient (48%) or physiological (15%). Only in a minority of cases, a significant underlying pathology of the urinary tract is found. Rare causes are an ectopic ureter, prune belly syndrome, urachal cysts and urethral atresia.¹⁹ The likelihood of an underlying abnormality correlates with the severity of the hydronephrosis. Transient or physiological hydronephrosis will mostly be mild, while ureteropelvic junction (UPJ) stenosis almost always presents with severe hydronephrosis. Tertiary care hospital usually do not have definite catchment area and complicated cases are more commonly encountered. Hence, prevalence calculated in this type of hospital-based study cannot be projected to the total population. Community based study should be ideal for true estimation of incidence of congenital anomalies in a population. Although congenital anomalies may be the result of one or more genetic, infectious, nutritional or environmental factors, it is often difficult to identify the exact causes. Some congenital anomalies can be prevented by vaccination, adequate intake of folic acid or iodine through fortification of staple foods or supplementation, and adequate antenatal care.

 

CONCLUSION

Antenatally diagnosed CAKUT were more common among male fetuses. Hydronephrosis was most followed by polycystic kidney disease, pelviureteric junction obstruction, posterior urethral valve were common congenital malformations of urinary tract noted. Majority required observation only while few required surgical intervention.

 

REFERENCES

1. Hildebrandt F. Genetic kidney diseases. Lancet 2010; 375: 1287–1295.
2. North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) 2008 Annual report. The EMMES Corporation: Rockville, MD, USA, 2008
3. Weber S, Moriniere V, Knuppel T et al. Prevalence of mutations in renal developmental genes in children with renal hypodysplasia: results of the ESCAPE study. J Am Soc Nephrol 2006; 17: 2864–2870
4. Adalat S, Bockenhauer D, Sarah E et al. Renal malformations associated with mutations of developmental genes: messages from the clinic. Pediatr Nephrol 2010; 25: 2247–2255
5. Weber S, Taylor JC, Winyard P et al. SIX2 and BMP4 mutations associate with anomalous kidney development. J Am Soc Nephrol 2008; 19: 891–803
6. van der Ven AT, Connaughton DM, Ityel H, Mann N, Nakayama M, Chen J, et al. Whole-exome sequencing identifies causative mutations in families with congenital anomalies of the kidney and urinary tract. J Am Soc Nephrol. 2018;29(9):2348–61.
7. Wühl E, van Stralen KJ, Verrina E, Bjerre A, Wanner C, Heaf JG, et al. Timing and outcome of renal replacement therapy in patients with congenital malformations of the kidney and urinary tract. Clin J Am Soc Nephrol [Internet]. 2013 Jan 7 [cited 2020 Jul 8];8(1):67–74.
8. Song R, Yosypiv I V. Genetics of congenital anomalies of the kidney and urinary tract [Internet]. Vol. 26, Pediatric Nephrology. Pediatr Nephrol; 2011 [cited 2020 Jul 8]. p. 353–64.
9. Fazecas TM, Araujo Junior E, Werner H, Daltro P, Peixoto AB, Lima GM et al. (2019) Applicability of magnetic resonance imaging in the assessment of fetal urinary tract malformations. Can Assoc Radiol J 70:83–89
10. Iacob, Daniela and Iacob, Emil and Boia, Marioara and Ilie, Constantin and Manea, Aniko. (2009). Methods To Diagnose Congenital Malformations In Newborns. 47-48.
11. Srivastava RN. Challenge of congenital abnormalities of the kidney and urinary tract. Asian J Pediatr Nephrol 2018;1:49-51.
12. Ameen, S.K., Alalaf, S.K. and Shabila, N.P. Pattern of congenital anomalies at birth and their correlations with maternal characteristics in the maternity teaching hospital, Erbil city, Iraq. BMC Pregnancy Childbirth 18, 501 (2018).
13. Hekmat Chaara et al. (2021). Antenatal Diagnosis of Renal and Excretory Tract Abnormalities: A Report of 36 Cases and Review of the Literature. Sch Int J Obstet Gynec, 4(4): 114-123.
14. Chougule A, Purkayastha J, Lewis L, Aiyappa G, Barche A. Study of Congenital Anomalies of the Kidneys and Urinary Tract in Neonates. J Nepal Paediatr Soc 2018;38(3):176-81.
15. Kumar BH, Krishnamurthy S, Chandrasekaran V, Jindal B, Ananthakrishnan R. Clinical Spectrum of Congenital Anomalies of Kidney and Urinary Tract in Children. Indian Pediatr. 2019 Jul 15;56(7):566-570.
16. Radhakrishna V, Kumaravel S, Priyamvada PS, Hanumanthappa N, Jindal B, Govindarajan K, Naredi BK, Rijhwani A. Clinico-Biochemical Profile of Children with Congenital Anomalies of the Kidney and Urinary Tract: A Cross-Sectional Study. Kidney Dis (Basel). 2019 Feb;5(1):51-57.
17. Mishra A. Renal agenesis: report of an interesting case. Br J Radiol 2007; 80: e167–e169
18. de Lucas C, Nocea A, San Roman J et al. Solitary kidney. Study of renal morphology and function in 95 children. Nefrología 2006; 26: 56–63
19. Hindryckx A, De Catte L. Prenatal diagnosis of congenital renal and urinary tract malformations. Facts Views Vis Obgyn. 2011;3(3):165-174.

 

 

 

 

 

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