Introduction

Definition of pyelectasis

Pyelectasis is abnormal widening of the renal pelvis, the kidney's funnel-shaped structure that holds urine before it moves into the ureter. It is usually diagnosed antenatally and occurs in 1–2% of pregnancies.¹

Causes and risk factors

Major causes

Ureteropelvic-junction obstruction (UPJO), vesicoureteral reflux (VUR), or temporary physiological causes (e.g., hyperproduction of foetal urine).

Risk factors

Male sex, history of urinary tract malformation in family, genetic predispositions (e.g., Down syndrome), and maternal conditions such as gestational diabetes.¹

Importance of early detection and management

Early recognition through antenatal ultrasound enables monitoring to avoid complications like urinary tract infection or renal damage. The majority of mild cases will resolve spontaneously, but the persistence of dilation may signify intrinsic pathology necessitating treatment.¹

Pyelectasis understanding

Physiological vs. pathological pyelectasis

• Physiological: Frequent in foetuses, usually resolves spontaneously in 96% of mild cases
• Pathological: With structural disease (e.g., UPJO, VUR) or obstruction (e.g., posterior urethral valves)

Severity grading

• Mild: Anteroposterior (AP) diameter of renal pelvis 4–7 mm prior to 28 weeks or 7–9 mm post
• Moderate: AP diameter 7–10 mm (second trimester) or 9–15 mm (third trimester)
• Severe: AP diameter >10 mm (second trimester) or >15 mm (third trimester), usually with calyceal dilation or thinning of the parenchyma

Possible complications

• Urinary tract infections from urinary stasis
• Development of hydronephrosis (kidney swelling due to urine backup)
• Acute kidney injury or pyelonephritis in rare instances¹

Role of antibiotic prophylaxis

Widespread antenatal screening has led to heightened detection of renal and urinary tract anomalies. Among the most frequently diagnosed congenital anomalies antenatally or postnatally are antenatal hydronephrosis (AHN) and vesicoureteral reflux (VUR). Pediatric urologists often use chronic antibiotic prophylaxis (CAP) for treating AHN, VUR, and ureterocele, unless definitive surgery is done. The primary goal of antibiotic prophylaxis (ABP) is to avoid urinary tract infection and long-term morbidity. However, the effectiveness of ABP has been the subject of much controversy, and paediatricians differ in their opinions regarding who should receive ABP. In this review article, we reviewed the literature available currently for evidence of the role of ABP in the context of AHN, VUR, and ureterocele.

A limited benefit of ABP for HN and VUR was demonstrated in most of our studies. The evidence for the use of CAP in ureterocele management is limited. Nevertheless, with the involvement of independent risk factors and other variables, a conclusion cannot be drawn from these studies. Pediatric urologists are encouraged to perform randomised controlled trials to compare patients followed up with and without ABP. Since there are no guidelines, an individualised approach must be employed for the application of ABP, until specific guidelines and recommendations are formulated.²

Indications for antibiotic prophylaxis

The medical management of VUR is directed towards prevention of recurrent UTI. Available evidence indicates that CAP decreases the recurrence rate of UTI until reflux disappears. Most lower-grade VURs resolve spontaneously with increasing age of the child .

As ureterocele is often accompanied by HN and VUR, the objective of ABP is to avoid the development of UTI prior to surgery. There are few trials conducted to establish the effectiveness of CAP in the treatment of ureterocele. Besson et al. assessed the frequency of neonatal UTI with a ureterocele.

Risks and considerations

Providers should also note the proposed but untested impact of chronic exposure to children of antibiotics. The CAP's advantages should be set against the established risk of bacterial resistance and adverse effects of the drug. Prophylactic antibiotic use in infancy has been linked with disadvantages and side effects, of which some relate to long-term use while others relate to temporary exposure for prophylaxis. CAP is writing a daily dosage of antibiotics ranging from one-quarter to one-half of the recommended dose. Nitrofurantoin, TMP/SMX, amoxicillin, and cephalosporins are generally the most preferred antibiotics in preventing UTI but are associated with adverse effects among children. Examples of adverse reactions in nitrofurantoin include gastrointestinal disturbance and skin reactions like urticaria and maculopapular rash.

Adverse reactions attributable to TMP/SMX are predominantly caused by the sulfamethoxazole moiety, usually cutaneous reactions. Severe adverse effects are unusual and are generally reversible when therapy is stopped. Early exposure to antibiotics is linked to an increased risk of the subsequent development of atopic diseases, such as eczema, wheeze, asthma, and allergy. The mechanism underlying this has been explained in the hygiene hypothesis, where increased hygienic living environment with less microbial exposure during childhood may augment atopic immunity. Another major disadvantage of CAP is antibiotic resistance. The RIVUR trial showed a high level of resistance to TMP/SMX in patients receiving prophylaxis with breakthrough UTI versus the patients receiving a placebo.

Limitation

Although this review presents additional evidence for the necessity of high-quality evidence in this area, it is not without significant limitations. Firstly, this review was constrained by the poor quality of evidence that was produced through merely reviewing observational studies. The observation that no randomised, controlled trials were discovered in this systematic review, and that most of the studies included were of poor quality, truly represents the status of the literature regarding prenatal HN. Another limitation arises from the inability to make any comment regarding associations between CAP use and gender, VUR status, HN grade, and circumcision status.

Since female sex , uncircumcised people, high-grade HN and VUR, and CAP recipients have been demonstrated in the past and in the present review to be at increased risk of UTI compared to their controls, it is wise to give CAP to infants with these features until appropriately power, high-methodological-quality studies confirm or disaffirm them.³

Summary

The position of ABP in the treatment of HN, VUR, and ureterocele remains debatable. The primary purpose of ABP is to avoid UTIs in at-risk children and in infants with HN, VUR, ureterocele, and other CAKUT. Some advantage of ABP was demonstrated in patients with high-grade HN and VUR. Conversely, trials involving mild HN and low-grade VUR did not demonstrate benefit with long-term CAP use. There is limited data regarding the use of CAP, in the context of ureterocele. The number of potential confounders restricts the generalisability of the results. There are no clear guidelines at present. Randomised, placebo-controlled trials with appropriate standardisation and stratification are most likely to be necessary for the creation of clear guidelines.

This systematic review indicates that CAP might have a weak but statistically non-significant protective effect on the rate of UTIs in infants with prenatal HN. Such a conclusion, however, has to be interpreted with great caution because of the very low quality of the evidence and numerous limitations of studies. The absence of clear guidelines in pediatric urology, combined with the shortcomings in the present literature offer sufficient proof of the need for well-documented, randomised, placebo-controlled studies examining the impact of CAP in this group.