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. Sometimes part of the urachus stays after birth. The urachus has no purpose after birth and if it stays 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 about 20 weeks into pregnancy.

Symptoms

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 from the belly button down to the lower pelvis.

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 two to three days. If the redness does not go away or gets worse, talk to your health care provider. If there is continued drainage or wetness of the belly button, it will most often go away on its own, but may need a surgery to correct.

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.

Diagnosis

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

Treatment

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 problem. It will heal after use of silver nitrate on the area. There are usually no long-term issues.

If There Is a Sinus (abnormal opening)

Drainage

Unlike the simple granuloma, that can be managed by a primary care provider,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 sometimes be confirmed by testing urea and creatinine levels in the fluid, but this is not always needed or easy to do. 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.

Sinogram

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.

Other Imaging

When there is no draining sinus to look into, ultrasound of the lower belly will often show a fluid-filled, enclosed lump, called a cyst, in the location of the urachus. In an adult, where there is a chance of cancer, abdominal and pelvic CT scans may also be helpful. Cysts are more common than cancer and are not as much of a concern, but can still lead to problems, such as infection.

Sometimes a voiding cystourethrogram, or VCUG (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 a blockage of the bladder outlet, which would also need to be treated. The likelihood of this is figured out by the patient’s age, gender and physical exam.

Surgery

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 and may lead to other problems, such as stones or more infections. Less than 1% of all bladder cancer occurs in the urachus and other problems are rare, but once the urachus has potentially become a problem, it should be removed.

If There Is No Sinus

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, but sometimes a procedure is needed to drain the cyst temporarily to help treat the infection.

Surgery

Again, complete removal of the urachus is of great value. After simple drainage with a needle, urachal abnormalities come back in about a third of patients. This is because the inside of the urachus is still present.

Other Methods

Cystoscopy

In some cases a direct look into the bladder with a cystoscopy can be helpful, but most urologists suggest using the methods talked about earlier in this article.

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.

Updated August 2024.


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