AUA Summit - What are Urachal Abnormalities?


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What are Urachal Abnormalities?

Before birth, there is a canal between the belly button and the bladder called the urachus. In most cases this canal goes away before birth. But sometimes part of the urachus remains after birth. The urachus has no purpose after birth, so if it remains it can cause health problems. These problems are called “urachal abnormalities.”

Problems with a urachal abnormality are rare. They can be seen in infants or children, and rarely in adults. It is unclear why this happens.

What Happens Under Normal Conditions?

As a baby develops, the bladder is formed in the lower belly of the growing fetus. This organ is joined with the umbilical cord by a thick cord called the urachus. After the first few weeks of growth, this thick path to and from the placenta has blood vessels, a channel (that will later become the intestine), and a tube called the allantois.

The inside of the allantois is joined to the top of the growing bladder. This link from the top of the bladder to the belly button is formed in about 20 weeks.


Because the urachus is found between the belly button and the top of the bladder, diseases of the urachus can appear anywhere in that space.

Visible Signs

In newborns and infants, drainage or “wetness” of the belly button that does not go away can be a sign of a problem. The most common problem at the belly button is a granuloma. This is an area that is reddened because the base of the umbilical cord stump did not heal correctly.

Sometimes the area can be very red even after the umbilical cord stump comes off. Dabbing a small amount of alcohol on the site twice a day will often lead to full healing in 2 to 3 days. If the redness does not go away or gets worse, talk to your health care provider.

Other Signs

There can also be urachal issues without wetness. About 35% of these problems are from an enclosed or infected urachal cyst. This type of problem is seen more often in older children and adults. Instead of visible belly button drainage, the signs are:

Other Health Issues around the Belly Button

There have been a few reports of other problems causing pain and swelling with the umbilical cord. These include infections of the remnant blood vessels. Also, the vitelline duct, between the belly button and the small intestine, sometimes has its own remnant problems. Sometimes a health problem like appendicitis or an ovarian cyst can mimic some of the signs of urachal problems.


The most common test used to diagnosis urachal anomalies is an ultrasound of the abdomen, bladder and pelvis.

For more information on ultrasounds please visit our Ultrasound article.


Most urachal problems can be found with a physical exam and ultrasound.

Chemical Cauterization for Umbilical Granuloma

This is done in the office of your primary care provider. An umbilical granuloma is a superficial abdominal wall problem. It will heal after treatment with antibiotics. There are usually no long-term issues.

If There Is a Sinus (abnormal opening)


Unlike the simple granuloma, umbilical wetness that does not go away should be looked at by a urologist.

About 65% of all urachal problems appear as a sinus or drainage opening at the belly button. Most of those are not connected all the way to the bladder. But a few cases have an open pathway from the bladder to the belly button. This is called a patent urachus. This can be confirmed by testing urea and creatinine levels in the fluid. These levels would be high if the fluid was urine from a bladder connection.

Antibiotics for Infection

Redness can be caused by this drainage, as well as infection of the skin. If there is pain or fever, or the redness spreads to nearby skin, you will need prompt antibiotic treatment and a possible hospital stay. This type of infection of the umbilical stump is called omphalitis. It can be from bacteria from a urachal sinus. Or it could be caused by something else in the belly button area that once joined to the bowels.


Once the swelling is controlled, the opening at the belly button can be looked at with a sinogram. A small tube is placed into the sinus opening and contrast dye flows in. X-rays are then taken to look at the channel. If the channel follows the path to the top of the bladder, the diagnosis is urachal sinus.


The urachus and all of its connections (plus a small amount of the top of the bladder) should be fully removed with surgery. Leaving any tissue behind could allow cancer to develop. Less than 1% of all bladder cancer occurs in the urachus. But once the urachus has potentially become a problem, it should be removed.

If There Is No Sinus


When there is no draining sinus to look into, ultrasound of the lower belly will often show a fluid-filled, enclosed lump in the location of the urachus. In an adult with a small chance of cancer, abdominal and pelvic CT scans may also be helpful.

Antibiotics for Infected Cysts

About 80% of infected cysts contain Staphylococcus aureus and many other types of bacteria. An infected cyst almost always stays in the same place. Rarely, an infected cyst will drain into the space between the stomach and other organs, causing inflammation and fever. Antibiotics will heal the infection.


Again, complete removal of the urachus is important. After simple drainage with a needle, urachal abnormalities come back in about a third of patients. This is because the linings and structures are still present.

Additional Methods

Voiding Cystourethrogram

Sometimes a voiding cystourethrogram (an x-ray using contrast dye) is useful even after a physical exam and ultrasound. This is done when the draining urachus is linked to bladder outlet obstruction, which would also need to be treated. This is most often settled by the patient’s age, gender and physical exam.


In some cases a direct look into the bladder with a cystoscopy can be helpful. But most urologists suggest using the methods previously mentioned.

After Treatment

After complete surgical removal of the urachus, there should be no further issues. There is no need for routine follow-up. But, you should reach out to your health care provider if you notice any changes.

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