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Megaureter - Types, Clinical Features, Diagnosis, and Treatment Measures

Published on Jul 22, 2022 and last reviewed on Feb 28, 2023   -  4 min read


Megaureter refers to a medical condition where the ureter is dilated more than average. This is a rare anomaly. To know more about this condition, read the following article.

Megaureter - Types, Clinical Features, Diagnosis, and Treatment Measures


The urinary tract is almost like a human plumbing system, and it consists of two kidneys, two ureters, a urinary bladder, and a urethra. Ureters are tubes that connect kidneys to the urinary bladder through which water and salts travel through to the bladder to be stored and are later excreted via the urethra. Most infants are born with entirely normal ureters, while some are born with wider ureters than others.

What Is a Megaureter?

Megaureter means larger ureter in layman terms. Ureters are known to be megaureters when they are wider than six or seven millimeters. This medical anomaly can cause problems such as obstructed urine flows and infections. If left untreated, this can lead to serious kidney problems. They are usually found during prenatal imaging. Megaureters are not a very common condition, but they are found four times more in males than in females. Megaureters can be caused due to a problem related to the ureter itself, which is called a primary megaureter. In some instances, the megaureter results from the blockage of the urinary bladder, which is known as the secondary megaureter.

Following are the types of megaureters:

  1. Primary Obstructed Megaureter: In this type of megaureter, the ureter near the bladder is constricted, which leads to the blockage of the ureter. This leads to the widening of the ureter further up. This condition can damage the kidney as time progresses, and medical care is required to avoid further severe complications related to the kidney.

  2. Refluxing Megaureters: This type of megaureter is commonly seen in newborn males and is characterized by the backflow of urine from the urinary bladder towards the kidney via the ureter. This is not a normal phenomenon as urine is not supposed to flow back from the bladder. This leads to the abnormal widening of the ureter. This is a sign of vesicoureteral reflux. Refluxing megaureters usually get back to normal during the first year of life, but if it does not, surgical treatments are required. Refluxing megaureters are often linked to other health problems like megacystis megaureter syndrome. Here, the reflux of urine along the ureter leads to improper drainage of urine and hence leads to the swelling of the bladder.

  3. Nonobstructive, Nonrefluxing Megaureters: Unlike the previously mentioned types, this type is not associated with any blockage or urinary reflux along the ureter. This type of megaureter usually gets back to normal without any treatment.

  4. Obstructed Refluxing Megaureters: This type of megaureter is a combination of both obstructive and refluxing megaureters and is known to be serious as it leads to extreme widening of the ureter. It can cause severe kidney complications if left untreated. People with this type of megaureter are often affected by urinary tract infections (UTI).

  5. Secondary Megaureters: This type occurs when the problem is not actually with the ureter itself. Instead, megaureter is a manifestation of other health conditions such as,

  • Prune belly syndrome.

  • Neurogenic bladder.

  • Posterior urethral valves (blocks in the male urethra).

What Are the Signs and Symptoms of a Megaureter?

Following are the common signs and symptoms associated with megaureter:

  • Frequent urinary tract infections.

  • Fever.

  • Nausea or vomiting.

  • Back pain.

  • Untreated megaureters can cause severe kidney problems.

How to Diagnose a Megaureter?

When a child experiences frequent urinary tract infections, or any of the symptoms mentioned above, your general physician or a urologist may ask for the following tests to make an exact diagnosis.

Ultrasound scans are scans taken with sound waves that bounce off the internal organs to produce images. This is a painless procedure that can help diagnose widened ureters in children. Ultrasound is performed during pregnancy to check the progress of the pregnancy, and many babies with congenital megaureters are usually diagnosed when they are in the uterus during regular ultrasound sessions.

Voiding Cystourethrogram (VCUG): This test is a specific type of x-ray done to diagnose vesicoureteral reflux. Here a dye is loaded into a catheter and is injected into the urinary bladder via the urethra. An x-ray is taken to diagnose if there is any reflux of dye from the urinary bladder into the ureter.

Diuretic Renal Scans: Diuretic renal scans are done to diagnose any blocks in the ureter and can also be done to assess the overall performance of the kidneys by injecting a radioactive liquid into the veins that reach the kidneys.

Magnetic Resonance of the Urinary Tract (Mr-U): This method provides accurate and more precise images of the kidneys and ureters than diuretic renal scans and ultrasound scans. However, this method is not used in small children as it might require general anesthesia or sedation.

How to Treat Megaureters?

After being diagnosed with megaureters, your doctor may opt for one of the following treatment options,

  • In most cases, megaureters resolve without treatment or surgery before the baby reaches its first age.

  • The doctor might prescribe antibiotics to prevent frequent urinary tract infections.

  • In some cases, when megaureters do not resolve within the first year of life, the doctor might go for open surgery. Here, a well-experienced surgeon who can deal with neonates should be assigned as extra care is required. During this surgery, the doctor removes the ureter, trims it, removes any blocks, and places it back into place.

  • Minimally invasive methods can also be done by using balloon methods where a balloon is used to stretch the narrow part of the ureter. This can also be done to remove blocks.


There is no way to prevent the occurrence of megaureter. However, a proper diagnosis can be done during regular checkups during pregnancy and can be treated as soon as possible to avoid severe kidney problems. In most cases, megaureters cure themselves before one year of age; therefore, regular visits to the urologist and frequent ultrasounds must be taken to keep the condition under control.

Frequently Asked Questions


What Does a Congenital Megaureter Mean?

The primary megaureter is also referred to as a congenital megaureter and occurs due to a blockage in the ureter itself. They are commonly diagnosed during prenatal investigations. They include:
- Obstructed megaureter.
- Refluxing megaureters.
- Nonobstructing, non-refluxing megaureters.
- Obstructed refluxing megaureters.


What Commonly Causes Hydronephrosis in Childhood?

Hydronephrosis refers to enlarged or dilated kidneys. About one in 100 fetuses may be diagnosed with hydronephrosis. In children, it most commonly occurs due to:
- Obstructed urinary tract.
- Abnormally developed kidneys.
- Congenital disabilities that affect the nerves controlling urinary retention.


What Are the Features of a Blocked Ureter?

A blocked ureter may cause the following symptoms:
- Fever.
- Frequent urination.
- Abdominal or flank pain.
- Nausea and vomiting.
- Incomplete emptying of the bladder.
- Swelling in legs.
- Urinary tract infections that keep recurring.


What Is the Surgical Method Used in Pediatric Megaureter?

The doctor may use the “wait-and-watch” approach for pediatric megaureters, as it resolves independently. The surgery is considered the last option, which may improve the urine flow.


How Does Megaureter Occur in Children?

Megaurter or enlarged ureter may occur due to any blockage in the urinary tract, resulting in urine backflow to the kidneys. It may eventually lead to enlarged kidneys. In addition, during the development of a fetus in the womb, the standard muscle layer in the ureter that aids in urine peristalsis may be replaced with fibrous tissue leading to a lack of urine flow to the bladder. It can also occur due to congenital disabilities that affect the nerves controlling urinary retention.


Is Megaureter Caused by Obstruction?

Megaureter mainly occurs due to obstruction in the ureter or the bladder. It leads to inappropriate urine voiding. Therefore, the urine stays in the ureter and flows back to the kidneys. Over time, it may result in:
- Recurrent urinary tract infections (UTI).
- Enlarged kidneys.


How Is a Primary Obstructive Megaureter Explained?

Megaurter most commonly develops when the baby grows in the mother’s womb. In the case of a primary obstructive megaureter, the blockage is present where the ureter meets the urinary bladder. Therefore, it results in improper urine flow to the bladder, which instead flows back to the kidneys. As a result, it gradually enlarges the ureter and the kidneys.


Do the Scars After Megaureter Surgery Look So Big?

If children have impaired kidney function due to a megaureter, the doctor may opt for open surgery, where the ureter is removed, trimmed, and replaced. The scars after the surgery may look big. However, alternatives like minimal invasive methods involve ballooning up the constricted portion of the ureter, and other laparoscopic surgeries may be done.


How Is Bleeding Controlled After TURP Surgery?

Transurethral resection of the prostate (TURP) is a surgical technique to manage enlarged prostate through resection. Fatigue, difficulty passing urine, and blood in the urine are expected for a few days after surgery. The doctor may advise drinking fluids to flush the surgical remnants. However, it is vital to seek medical attention if bleeding increases.

Last reviewed at:
28 Feb 2023  -  4 min read




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