Learn about hydronephrosis, a condition where urine backs up into the kidneys, causing swelling and pain. Find out the causes, symptoms, and treatments for hydronephrosis at Meri Sehat.

Hydronephrosis

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Saad Ullah Siddiqui

Overview

Hydronephrosis is defined as the swelling of one or both kidneys due to a build-up of urine. 
&nbsp;

Hydronephrosis is not a primary disease. It&#39;s a secondary condition caused by another underlying disease, most commonly a blockage or obstruction in the urinary tract. This causes the urine to accumulate in the kidneys, causing swelling.

Hydronephrosis can affect anyone at any age. In children, it is sometimes detected during infancy or a prenatal ultrasound before the baby is born. Hydronephrosis does not always manifest as a symptom.

An obstruction of the ureteropelvic junction (UPJ) is the most common cause of hydronephrosis in neonates and infants. Approximately 1 in 100 live births in the United States present with this obstruction.<a href="#accordion">[4]</a> Whereas, in young adults, nephrolithiasis is the most common cause of hydronephrosis. Moreover, hydronephrosis is seen in 80% of pregnant women.<a href="#accordion">[4]</a> 
&nbsp;

Hydronephrosis is classified into two types: 
&nbsp;

<ol>
	<li>
	<h5>&nbsp;Obstructive Hydronephrosis</h5>
	</li>
</ol>

This type of hydronephrosis is caused by a physical obstruction in the urinary tract, which restricts urine flow. The obstruction can occur anywhere along the urinary tract, from the kidneys to the bladder, and can be caused by several factors, including kidney stones, tumors, or an enlarged prostate. 
&nbsp;

<ol start="2">
	<li>
	<h5>&nbsp;Non-Obstructive Hydronephrosis</h5>
	</li>
</ol>

This type of hydronephrosis is caused by a functional problem in the urinary tract that prevents urine from flowing normally. Non-obstructive hydronephrosis can be caused by conditions such as vesicoureteral reflux, in which urine flows backward from the bladder into the ureters, or neurogenic bladder, in which the nerves that control bladder function are damaged.

Hydronephrosis can also be classified according to its severity and extent. 
&nbsp;

<ul>
	<li>Mild Hydronephrosis </li>
</ul>

It is characterized by minimal dilation of the renal pelvis and calyces.

<ul>
	<li>Severe Hydronephrosis</li>
</ul>

It is characterized by significant dilation and stretching of the renal pelvis and calyces, resulting in kidney damage and function loss.

Hydronephrosis can be unilateral (affecting only one kidney) or bilateral (affecting both kidneys) in some cases. According to the research, a unilateral blockage can result in a gradual decline in renal function in 20&ndash;40% of individuals<a href="#accordion">[2]</a>. The severity and type of hydronephrosis will be determined by the underlying cause of the condition as well as the duration of the obstruction or functional problem. 
&nbsp;

Signs and Symptoms

Normally, urine flows through the urinary tract with little pressure. If the urinary tract is obstructed, pressure can build up. The kidney may enlarge if urine accumulates for an extended period. It may become engorged with urine to the point where it presses on nearby organs. If left untreated for too long, this pressure can permanently damage the kidneys. 
&nbsp;

Mild hydronephrosis symptoms include frequent urination and an increased desire to urinate. Other potentially serious symptoms include:

<ul>
	<li>Abdominal or flank pain</li>
	<li>Nausea</li>
	<li>Vomiting</li>
	<li>Discomfort urinating</li>
	<li>Incomplete voiding, or bladder emptying</li>
	<li>Fever 
	&nbsp;</li>
</ul>

Interrupting the flow of urine raises the risk of a urinary tract infection (UTI). This is why urinary tract infections (UTIs) are one of the most common complications of hydronephrosis. Some symptoms of a UTI are as follows:

<ul>
	<li>Cloudy urine</li>
	<li>Painful urination</li>
	<li>Burning micturition</li>
	<li>A weak urine stream</li>
	<li>Back pain</li>
	<li>Bladder pain</li>
	<li>Fever</li>
	<li>Chills 
	&nbsp;</li>
</ul>

Note: If you notice signs of hydronephrosis, make an appointment with your healthcare provider to discuss your symptoms.&nbsp; Treat UTIs promptly, since if left untreated, it can lead to serious complications such as pyelonephritis, a kidney infection, sepsis, a bloodstream infection, or blood poisoning. 
&nbsp;

Causes

The following are the most common causes of adult hydronephrosis: 
&nbsp;

<ul>
	<li>Kidney Stones</li>
</ul>

Stones can get stuck in the kidneys or urinary tract., obstructing urine flow and causing hydronephrosis. 
&nbsp;

<ul>
	<li>Cancer</li>
</ul>

Tumors in the bladder, prostate gland, uterus, or other organs in or near the urinary tract can cause blockages in the urinary tract that disrupt urine flow. 
&nbsp;

<ul>
	<li><a href="https://merisehat.pk/disease/benign-prostatic-hyperplasia">Benign Prostatic Hyperplasia (BPH)</a></li>
</ul>

Enlargement of the prostate gland in men can put a strain on the urethra. 
&nbsp;

<ul>
	<li>Blood Clots</li>
</ul>

The presence of blood clots in the ureter or kidney can obstruct urine flow. 
&nbsp;

<ul>
	<li>Narrowing Or Stricture Of The Urinary Tract</li>
</ul>

An injury, infection, birth defects, or surgery can cause narrowing of the urinary tract. 
&nbsp;

<ul>
	<li>Nerve Or Muscle Problems</li>
</ul>

These problems can affect the kidneys or ureters, for example, from <a href="https://merisehat.pk/disease/diabetes-type-1-and-2">diabetes mellitus</a>. 
&nbsp;

<ul>
	<li>Urinary Retention</li>
</ul>

Urine may be trapped inside the body because of the inability to empty the bladder. 
&nbsp;

<ul>
	<li>Vesicoureteral Reflux</li>
</ul>

In this case, urine flows backward from the bladder to the kidneys. 
&nbsp;

<ul>
	<li>Uterocele</li>
</ul>

In this case, the lower portion of the ureter may protrude into the bladder. 
&nbsp;

<ul>
	<li>Pregnancy</li>
</ul>

As the uterus expands, it can press on the ureters, obstructing urine flow. 
&nbsp;

<ul>
	<li>Uterine Prolapse</li>
</ul>

This is characterized by the uterus sagging or slipping out of its normal position. 
&nbsp;

<ul>
	<li>Cystocele (Fallen Bladder)</li>
</ul>

A condition in which the wall between the bladder and vagina weakens, allowing the bladder to droop into the vagina. 
&nbsp;

There are no routine screening tests for hydronephrosis. However, antenatal ultrasound scans can help detect fetal hydronephrosis or anatomical defects of the kidneys and urinary tract that may be contributing to the condition. 
&nbsp;

Diagnosis

Early diagnosis can help prevent complications or permanent damage to the kidneys. To establish a diagnosis, the doctor will first get an overall assessment of the patient&rsquo;s health status and any urinary symptoms. During a physical examination, the patient&rsquo;s abdomen and flank area are palpated for an enlarged kidney. 
&nbsp;

Additionally, the following tests are required to confirm hydronephrosis: 
&nbsp;

<ul>
	<li>Ultrasound Of The Kidneys And Bladder</li>
</ul>

This imaging technique creates images of the kidney and bladder by using high-frequency sound waves. Ultrasound can detect organ-structural flaws and may also reveal swollen kidneys in the baby, an indication of primary vesicoureteral reflux. 
&nbsp;

<ul>
	<li>Specialized X-Ray Of The Urinary Tract System</li>
</ul>

This test detects abnormalities by taking X-rays of the bladder when it is full and emptying. A thin, flexible tube (catheter) is inserted through the urethra and into the bladder. The child&#39;s bladder is X-rayed in various positions after contrast dye is injected into the bladder via a catheter. Moreover, X-rays of the bladder and urethra are taken during urination to determine whether the urinary tract is functioning properly. The test is associated with side effects, such as catheter discomfort or having a full bladder, as well as the possibility of a new urinary tract infection. 
&nbsp;

<ul>
	<li>Nuclear Scan</li>
</ul>

This test employs a radioisotope tracer. The scanner detects the tracer and indicates whether the urinary tract is working properly. The risks include catheter discomfort and urination discomfort. 
&nbsp;

Treatment

The goal of treatment is to restore urine flow from the kidney and reduce swelling and pressure caused by urine build-up. Treatment is based on the underlying condition, as that is the primary problem.

If the hydronephrosis is acute or sudden, a stent or soft tube (nephrostomy tube) can be inserted through the skin into the kidney to drain excess urine. A urologist may place a soft plastic tube called a ureteral stent between the kidney and bladder during a cystoscopy to drain excess fluids.

Treatment options for hydronephrosis caused by kidney or ureter stones may include: 
&nbsp;

<ul>
	<li>Shock Wave Lithotripsy</li>
</ul>

This is the most commonly used treatment for kidney stones. A machine emits high-energy shock waves to break up the stones into dust or smaller fragments, allowing them to pass out of the body. 
&nbsp;

<ul>
	<li>Ureteroscopy</li>
</ul>

A thin tube containing specialized instruments may be inserted into the urethra, allowing a doctor to break up and remove the stones. This method is most commonly used for bladder or lower ureter stones.

To break up stones, ureteroscopy can be used in conjunction with other techniques, such as a pulsed dye laser or electrohydraulic lithotripsy. This is the preferred method for pregnant women, patients with blood clotting disorders, and those with Class III <a href="https://merisehat.pk/disease/obesity">obesity</a>. 
&nbsp;

<ul>
	<li>Surgery</li>
</ul>

When kidney stones become too large or difficult to remove, they may need to be surgically removed. Surgery may also be required in case of tumors or other types of blockages. 
&nbsp;

<ul>
	<li>Medications </li>
</ul>

<ol>
	<li>&nbsp;Urinary tract infections can be treated or prevented with antibiotics.</li>
	<li>&nbsp;Analgesics can be used for the management of alleviating pain. 
	&nbsp;</li>
</ol>

Early detection and treatment of hydronephrosis can aid in the prevention of complications and the preservation of kidney function. Untreated or severe hydronephrosis can lead to: 
&nbsp;

<ul>
	<li>Urinary Tract Infections - This is the most common complication of hydronephrosis.</li>
	<li>Renal Scarring - If UTIs are left untreated, it can lead to scarring of the kidney, resulting in permanent damage. This may lead to hypertension and kidney failure.</li>
	<li>Hypertension - Damage to the kidneys results in high blood pressure.</li>
	<li>Kidney Failure - Renal scarring results in loss of kidney function, causing acute kidney failure. This can progress to chronic kidney disease.</li>
	<li>Pyelonephritis</li>
	<li>Sepsis 
	&nbsp;</li>
</ul>

The following factors increase the risk of hydronephrosis: 
&nbsp;

<ol>
	<li><a href="https://merisehat.pk/disease/kidney-stones-66">&nbsp;Kidney Stones</a></li>
</ol>

These mineral and salt deposits can clog the urinary tract and cause hydronephrosis.

<ol start="2">
	<li>&nbsp;Enlarged Prostate</li>
</ol>

Men with an enlarged prostate may experience urinary tract obstruction, which can cause hydronephrosis.

<ol start="3">
	<li>&nbsp;Urinary Tract Infections</li>
</ol>

Urinary tract infections can cause inflammation and swelling, leading to hydronephrosis.

<ol start="4">
	<li>&nbsp;Congenital Abnormalities</li>
</ol>

Some people are born with urinary tract abnormalities that can lead to hydronephrosis.

<ol start="5">
	<li>&nbsp;Cancer</li>
</ol>

Tumors in the urinary tract or nearby organs can cause blockages and result in hydronephrosis.

<ol start="6">
	<li>&nbsp;Injury</li>
</ol>

Urinary tract trauma can result in swelling and blockages, which can lead to hydronephrosis.

<ol start="7">
	<li>&nbsp;Neurological Conditions</li>
</ol>

Hydronephrosis may be more common in people who have neurological conditions that affect the bladder or urinary tract. 
&nbsp;

It is important to note that having one or more of these risk factors does not guarantee that a person will develop hydronephrosis. However, they should be aware of the increased risk and consult their doctor if they experience symptoms. 
&nbsp;

Because hydronephrosis is caused by an underlying condition, prevention is dependent on avoiding or treating the underlying condition as soon as possible. For example, going to a stone clinic to determine the cause of the stones and begin treatment to prevent recurrence may reduce the likelihood of developing a kidney stone. 
&nbsp;

Note: Seek medical attention right away if you have severe pain in your side or abdomen, vomiting, or a fever of more than 100.5 degrees Fahrenheit. 
&nbsp;

The Use of Biomarkers in the Diagnosis and Treatment of Obstruction of the Upper Urinary Tract in Children<a href="#">[3]</a>. 
&nbsp;

<ol>
	<li>&nbsp;NGAL</li>
</ol>

A member of the lipocalin protein family, NGAL is an organ-specific protein. In individuals with severe hydronephrosis caused by UPJ obstruction, prospective clinical trials have revealed considerably greater levels of NGAL (normalized to urinary creatinine) in urine samples from the bladder of ill children in comparison to unaffected children. 
&nbsp;

<ol start="2">
	<li>&nbsp;CA 19-9</li>
</ol>

Tumor-associated marker CA 19-9 is a member of the group of carbohydrate antigens. Elevated CA 19-9 levels have been seen in secondary hydronephrosis brought on by ureterolithiasis in both urothelial malignancies and non-tumor situations. Three studies found that individuals who had signs of UPJ blockage had preoperative levels of CA 19&ndash;9 that were noticeably greater than those in the healthy control group. 
&nbsp;

<ol start="3">
	<li>&nbsp;TGF &beta;1</li>
</ol>

TGF-1 is a polypeptide that is a member of the cytokine superfamily. It is believed that the presence of this marker in urine may serve as a non-invasive technique for tracking the effectiveness of surgery and assessing the course of renal disease.

In three publications, TGF&beta;1 levels evaluated in urine were considerably increased prior to surgery in operated children with UPJ blockage compared to a healthy control group. 
&nbsp;

<ol start="4">
	<li>&nbsp;MCP1</li>
</ol>

Chemokine protein MCP1 controls the movement of monocytes. In the situation of obstruction, its expression at the levels of the renal tubules seems to be closely correlated with the buildup of these inflammatory cells throughout the interstitial space. Hence, the rate of monocyte infiltration and subsequent advancement of interstitial renal fibrosis may be correlated with urine excretion of MCP1. 
&nbsp;

<ol start="5">
	<li>&nbsp;KIM 1</li>
</ol>

Type I transmembrane glycoprotein (KIM 1) is potentially employed as an early and sensitive urine biomarker of renal dysfunction in obstructive nephropathy since it cannot be found in healthy children. However, it is abundantly expressed and secreted by injured proximal tubule epithelial cells, unless they are fully repaired. 
&nbsp;

Key Points

<ul>
	<li>Hydronephrosis is a condition in which urine accumulates in the kidneys as a result of a urinary tract obstruction.</li>
	<li>A variety of factors, including kidney stones, tumors, an enlarged prostate, and congenital abnormalities, can cause the obstruction.</li>
	<li>Hydronephrosis symptoms include back or side pain, frequent urination, and difficulty urinating.</li>
	<li>Imaging tests such as ultrasound, CT scan, or MRI are commonly used in diagnosis.</li>
	<li>Treatment is determined by the underlying cause of the obstruction and may include medications to alleviate symptoms, surgery to remove the obstruction, or a catheter to drain the urine. 
	&nbsp;</li>
</ul>

[1] Gemer O, Bergman M, Segal S. Prevalence of hydronephrosis in patients with genital prolapse. Eur J Obstet \& Gynecol Reprod Biol. 1999;86(1):11–3.

[2] McDougal WS, Wein AJ, Kavoussi LR, Partin AW, Peters CA. Campbell-Walsh urology 11th Edition review e-book. Elsevier Health Sciences; 2015.

[3] Seifriedova Z, Flogelova H, Sarapatka J, Smakal O, Student V, others. The use of biomarkers in the diagnosis and treatment of obstruction of the upper urinary tract in children. Biomed Pap. 2022;166(3):243–50.

[4] Thotakura R, Anjum F. Hydronephrosis And Hydroureter. [Updated 2022 Sep 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-.