Introduction

This medical condition, called pyelectasis occurs when a fetus's renal pelvis widens, urine gathers in this region at the highest part of the kidney before entering the ureter. In the second or third trimester of pregnancy, it is frequently found during regular ultrasounds. The prevalence of pyelectasis is low, often occurring in 1 to 5% of pregnancies.¹

Pyelectasis can occasionally be an indication of additional problems which affect the kidneys or urinary tract, even though it can also be benign and go away on its own. These may consist of kidney blockage, hydronephrosis, or urinary tract infections (UTIs). Postnatal follow-up is usually necessary to evaluate the baby's kidney health and avoid long-term damage because of these possible dangers.²

The aim of this article is to examine how pyelectasis might impact kidney function, and how if left untreated, it may result in long-term issues.

Causes and types of Pyelectasis

There are three primary kinds of pyelectasis: isolated, acquired, and congenital. Mild pyelectasis, also known as congenital pyelectasis, occurs before birth. It shows up on an ultrasound as a dark oval or spherical form that is 5-10 mm across the kidney.³ This typically occurs as a result of a little delay in the rate at which urine drains, because the kidney-ureter link is still developing. The renal pelvis may appear larger as a result of this excess fluid.

Congenital pyelectasis is occasionally linked to down syndrome, however, it is typically not linked to significant long-term issues. Also, there may be a marginally higher chance that the child will have down syndrome if it is discovered in conjunction with other indicators or anatomical abnormalities.

In contrast, acquired pyelectasis happens after birth and is usually brought on by an obstruction in the urinary tract. Depending on whether the pressure is internal to the urinary system or external, these blockages can be categorised as intrinsic or extrinsic.⁴ Pressure from the outside, such as from a nearby organ or mass, is referred to as extrinsic compression, while the urinary system itself is the source of intrinsic compression. Common reasons include tumours, benign prostatic hyperplasia (enlarged prostate), renal cysts, kidney stones, and ureteropelvic junction stenosis (constriction at the kidney-ureter junction).

The diagnosis of isolated pyelectasis is made in the absence of any additional abnormalities. Although, this frequently goes away on its own without treatment, it still has to be watched to make sure it doesn't worsen.

The impact of Pyelectasis on kidney function

The condition known as hydronephrosis or kidney enlargement, brought on by the build-up of urine, is mildly represented by pyelectasis. Urine may become trapped as a result of the renal pelvis expanding, increasing pressure in the urinary collecting system. Hydrostatic pressure is the term for this elevated pressure, which over time, may have an impact on kidney function.

Let's take a quick look at how the kidney functions before we go further.

The kidneys are organs that create urine by filtering blood and eliminating waste and extra water. This keeps a balance of minerals, water, and salt in the blood.⁵ The first step in the process is glomerular filtration, in which fluid, glucose, ions, and waste products are moved from the blood into the kidney's filtering units or nephrons, by hydrostatic pressure. Following filtration, the nephron's tubular components modify the filtrate's makeup, and they accomplish this by secreting waste items into the urine and reabsorbing vital substances into the bloodstream. The body will then retain what it needs and eliminate what it doesn't, due to this procedure.

This balance is upset when pyelectasis slows down or blocks the flow of urine. The first and most important step in the kidney's process of cleaning your blood by glomerular filtration may be hampered by the elevated pressure. If left untreated for an extended period of time, this could lead to kidney damage or severe hydronephrosis.

The kidneys can usually heal if the obstruction is short-term or addressed quickly. We call this acute hydronephrosis. On the other hand, chronic hydronephrosis, which can result in scarring, kidney tissue weakening, and ultimately irreversible damage, can develop if the obstruction persists for an extended period of time. The kidney can contract, and the filtration unit can become scarred and compressed.

Risk elements for prolonged damage

The degree of pyelectasis and how it develops over time can be used to estimate the likelihood of long-term harm. Based on the result of ultrasounds, doctors frequently use a scale to rate the degree of kidney dilation. These grades aid in assessing the extent of kidney damage and serve as a guide for treatment choices.

This is an explanation of the grading scheme:

• Grade 0: the kidneys show no signs of dilatation
• Grade 1: only the renal pelvis is dilated
• Grade 2: renal pelvic and major calyceal dilation
• Grade 3: there is pelvic dilation of the major and minor calyces while renal tissue remains intact⁶
• Grade 4: it is similar to grade 3, but with obvious renal cortex thinning, signifying more severe hydronephrosis

The prevalence of UTI and vesicoureteral reflux (when urine travels backwards from the bladder to the kidneys), and whether both kidneys are impacted, are other factors that may raise the risk of long-term kidney problems.

Observations and diagnosis

Pregnancy-related ultrasound scans typically reveal pyelectasis for the first time in the second or third trimester. In order to track whether the problem improves, stays constant, or gets worse as the pregnancy progresses, doctors will arrange for follow-up scans.

A postnatal renal ultrasonography may be recommended for the newborn if pyelectasis was present during pregnancy, and this scan is frequently performed in the first few days or weeks of life. Additional testing might be required if the ultrasound reveals dilation that is ongoing or getting worse.

DMSA scan aids in checking the kidney’s structure and to see if there has been any scarring. The MAG3 renogram is also used to assess the kidney’s ability to drain and function. These tests aid in determining the extent of kidney damage and whether a blockage exists.

Additionally, a voiding cystourethrogram (VCUG) test which is used to check for vesicoureteral reflux may be suggested by doctors.

Tests for blood and urine are frequently performed in addition to imaging. To evaluate kidney function, they include serum creatinine and electrolyte level tests, and finding infections or other issues can be aided by urinalysis. Along with keeping an eye out for symptoms like low weight gain or developmental delay, paediatricians will also track the baby's health and look for indications of UTIs.

Therapy and handling

Many mild occurrences of pyelectasis go away on their own without any medical intervention. The method used however, is determined by the severity of the condition when intervention is required. Continuous antibiotic prophylaxis (CAP) is a popular management approach that can be used to prevent urinary tract infection, which is more common in children with urinary tract abnormalities like pyelectasis or hydronephrosis by administering the low-dose to them.

Surgery could be necessary in more severe situations such as pyeloplasty, which is a popular operation performed to address ureteropelvic junction blockages. Children with severe blockage and impaired kidney function can benefit from this safe and efficient treatment, according to research.⁷

To evaluate kidney function over time and make sure that no additional damage occurs, it is frequently necessary to have regular follow-up appointments with paediatric nephrologists or urologists.

FAQs

Is pyelectasis recurrent?

If your baby's pyelectasis goes away and their kidney function is normal, acquired pyelectasis normally doesn't come back. However, it can arise later due to other factors, including kidney stones or infections.

Will my baby's kidney function be impacted in the long run by pyelectasis?

Pyelectasis typically doesn't result in long-term issues. However, if it is associated with significant hydronephrosis or an obstruction, it might cause kidney damage if treatment is not received. Frequent observation lowers this risk.

Does down syndrome have a connection to pyelectasis?

Babies with down syndrome are more likely to have mild pyelectasis, particularly if it is discovered in conjunction with other indicators. However, it typically doesn't significantly raise the danger on its own.

Summary

The renal pelvis, the area of the kidney where urine gathers before emptying into the bladder, widens in pyelectasis. It may be transient or an indication of a more serious problem, and it is frequently found during standard prenatal ultrasounds. Persistent pyelectasis may indicate renal issues or obstructions in the urinary tract, though many cases go away on their own. Based on severity and aetiology, this disorder is categorised as either acquired (developing later), isolated (with no other abnormalities), or congenital (existing prior to birth).

Chronic blockage can eventually harm the kidneys if treatment is not received. After birth, follow-up testing may include blood or urine tests, renal function imaging, and ultrasound, hence, monitoring is crucial. Antibiotics or surgery might be necessary in certain situations. To avoid long-term issues and promote healthy kidney growth, it is essential to comprehend how pyelectasis impacts kidney pressure and urine flow.