What is Patent Urachus?

Patent urachus is one type of a few rare disorders often referred to as urachal anomalies. These disorders happen when certain embryologic tissues, which serve to empty the fetal bladder before birth, don’t disappear as they’re supposed to. Depending on the location and amount of tissue that still remains, the symptoms a person experiences can vary. Some urachal anomalies are apparent right at birth, while others are less obvious and might not be diagnosed until adulthood, or might only be found when imaging tests are done for unrelated reasons.

Historically, it was common to remove these tissues surgically because of the risk of them becoming cancerous. However, recent research has suggested that because of the rarity of the condition and the very low risk of it developing into cancer, early surgical removal may not be necessary.

Still, it’s crucial to promptly and accurately diagnose urachal anomalies in children who have symptoms such as a wet umbilical cord, ongoing drainage, repeated urinary tract infections, and recurrent infections around the belly button. This is important for alleviating symptoms, preventing severe recurring infections, and providing effective treatment.

What Causes Patent Urachus?

During the fourth week of a baby’s development in the womb, the tiny three-layered disk that will become the baby turns into a cylindrical shape. At this point, several important parts that play a key role in the baby’s growth, like the umbilical vessels (two umbilical arteries and one umbilical vein), urachus, and omphalomesenteric duct, enter into the narrowed interface between the yolk sac and the embryonic disk. The omphalomesenteric duct, which connects the developing gut to the yolk sac is particularly important.

This is also the time the allantois forms to become the urachus. This urachus serves as a connection between the developing bladder to the naval (or umbilicus). Usually, the urachus disappears at the end of gestation before birth, but some believe that this happens in the first few days after birth. What remains is a fibrous cord in the preperitoneal (area before the belly lining) space between the naval (umbilicus) and the bladder.

If the urachus doesn’t completely disappear as it should, it leads to urachal anomalies. These are linked to the amount and location of any leftover tissue.

The total failure of the urachus to disappear results in a patent urachus, which is an open passage between the bladder and the naval. Bladder diverticulum happens when there is persistent tissue left at the bladder without any connection to the naval. If there’s persistent tissue at the naval with no connection to the bladder, it’s called an umbilical polyp or sinus. A urachal cyst results when a part of the urachus remains open, but there is closure of the passage at both ends near the naval and the bladder.

Risk Factors and Frequency for Patent Urachus

Urachal anomalies refer to conditions where there is an issue with the urachus, a structure found in the human body. These conditions are usually hard to track because they often don’t cause symptoms or remain undiagnosed. One specific type of these anomalies, called a “true patent urachus,” is especially rare. A study done at the Hospital for Sick Children in Toronto, Canada, showed that only 1.03% of their general pediatric population had any form of urachal anomaly, and an even smaller fraction, 1.5%, was diagnosed with a true patent urachus.

A true patent urachus is normally diagnosed early, thanks to clear signs like constant leakage of urine from the belly button. Additionally, these urachal anomalies have a link to a condition known as posterior urethral valves, a situation that can block urine flow. As a result, the condition is three times more common in male children compared to female children.

Urachal anomalies are conditions that can often go unnoticed due to lack of symptoms or diagnosis.
One type of urachal anomaly, true patent urachus, is very rare.
According to a study, 1.03% of children had some form of urachal anomaly, but only 1.5% had a true patent urachus.
A true patent urachus typically shows early signs, such as constant urine leakage from the belly button.
The condition is often associated with posterior urethral valves, leading to urine flow blockage.
Consequently, urachal anomalies are three times more prevalent in male children than in females.

Signs and Symptoms of Patent Urachus

An umbilical cord usually measures about 1.5 cm across and 3.6 cm around. If the cord seems too thick, it might point to a urachal abnormality, which needs further investigation. Sometimes, there are no obvious issues at birth, but later, babies or older kids might show symptoms like continuous drainage from the belly button. This discharge typically smells like urine. Umbilical polyps, which are abnormal growths, could also cause belly button drainage. These polyps often don’t respond to silver nitrate, a common treatment.

Other symptoms like belly button inflammation, stomach pain, pain above the pubic bone, or a noticeable mass, particularly in correlation with urachal cysts, might occur later in a child’s life. During a physical check-up, the healthcare provider should look for any irregularities around the belly button, or sinus tracts (small abnormal channels) near it. They would also look for any masses that can be felt just below or behind the belly button, and check for movement or discharge from the belly button when the child pees or when mild pressure is applied to their bladder.

Testing for Patent Urachus

If a newborn baby has a visible issue with their umbilical cord, an ultrasound can help provide more information and confirm a diagnosis. If the ultrasound shows thickened tissue that could be connected to the bladder, another ultrasound should be done between six and twelve months later.

If the baby has a condition called a patent urachus, in which the connection between the bladder and the umbilical cord that normally disappears before birth remains open, they should have a test called a voiding cystourethrogram. This test can show if there are any other abnormalities in the urinary system, such as posterior urethral valves, which are extra flaps of tissue in the tube that carries urine from the bladder out of the body. In these cases, the patent urachus may be the only way for urine to leave the body.

If a child keeps getting their belly button wet, the doctor should check to see if there’s an abnormal opening in the belly button or any unusual lumps near or behind the belly button. If it’s not clear whether the fluid coming from the belly button is urine, a sample can be tested for creatinine, a waste product that’s usually present in urine. If there is a visible opening, they may have a test called a sinogram, where a dye is injected into the opening so it can be seen more clearly. However, this test is difficult to do in children and is more commonly used in adults.

Repeated belly button or urinary tract infections can sometimes mean the child has a urachal cyst, which is a pocket of fluid near the belly button. The infections are usually caused by skin bacteria or a family of bacteria called Enterobacteriaceae. Even though it’s not always necessary, CT scans are often done before a child is seen by a surgeon who specializes in treating children. This is because CT scans are very good at identifying these issues.

Treatment Options for Patent Urachus

A patent urachus, a tube connecting the bellybutton and bladder that is normally severed prior to birth but remains open in some cases, requires surgical removal. This is important to avoid recurrent bladder infections and skin damage around the bellybutton. For newborns or young children, surgeons often opt for open surgery due to its simplicity and less visible scarring.

In performing this surgery, surgeons aim for a complete removal of the patent urachus, including the bladder portion to which it attaches. The bladder is then secured with dissolvable stitches. In instances where an extensive bladder repair is necessary, some surgeons may place a tube, known as a Foley catheter, in the bladder post-surgery for one to three days to assist with urination.

As the child grows, a laparoscopic surgery, which uses smaller incisions, may become a better option as it helps avoid a larger incision across the abdomen. Similar to the earlier method, a two-layer bladder repair is still recommended. However, if the child has an infected belly button, the wound must first heal for around 4 to 6 weeks after drain and treatment with antibiotics before the surgery is performed. This process helps in avoiding bladder leaks.

In some children with a urachal anomaly, a type of disorder involving the urachus, the decision about whether to operate can be tricky, especially if they show no symptoms. In such cases, some surgeons choose to monitor these patients over time rather than opting for immediate surgery. There are even suggestions that a mild inflammation might naturally close off the remaining structure. Yet, if surgery is not performed, it’s important to discuss the potential future risks, including the very low probability of a certain type of cancer, with the child’s family.

When a baby is born with a noticeably large umbilical cord, certain health-related issues may need to be checked. These could include:

Gut contained within the umbilical cord
Omphalomesenteric duct (a tube that joins the baby’s midgut to the yolk sac)
Urachus that hasn’t closed properly (a tube between the baby’s bladder and belly button)
Unusual blood vessel formations

An ultrasound may be done, especially if there’s suspicion of a urachus or omphalomesenteric duct that hasn’t closed up as it should.

If a baby’s belly button seems consistently wet, this could be due to an umbilical granuloma. This usually looks like a moist, reddish lump of tissue in the belly button. It can often be treated in a doctor’s office using a substance called silver nitrate. If this doesn’t work, it may indicate an umbilical polyp (a growth), which may stem from the omphalomesenteric duct or the urachus.

A patent omphalomesenteric duct – one that remains open – may also cause a discharge from the belly button, which looks similar to digestive fluids. A urachal cyst may show up as a lump or swelling at the belly button. However, in most cases of children, this is usually an umbilical hernia.

In any scenario where the belly button of a newborn baby discharges pus, is harder or redder than normal and is sensitive to touch, omphalitis – an infection of the umbilical cord stump – could be suspected. This condition should never be overlooked.

What to expect with Patent Urachus

Children with isolated urachal anomalies, which are unusual features of a tube connecting the belly button and bladder, typically have an excellent outlook. However, it’s important not to miss the possible presence of posterior urethral valves. These are flaps of tissue in the tube that carries urine from the bladder out of the body, which can cause problems in infants with a completely open urachus (tube). It’s also worth mentioning that 25% to 30% of children with prune belly syndrome have an open urachus. Prune belly syndrome is a condition characterized by a lack of abdominal muscles, causing the skin of the belly area to wrinkle like a prune.

Possible Complications When Diagnosed with Patent Urachus

In the case of a patent urachus, repeated bladder and belly button infections can lead to serious health issues. Although complications after surgery are uncommon, they can happen and include infection at the wound site, and in more severe cases, leakage of urine into the abdominal cavity.

Common Side Effects:

Repeated bladder infections
Belly button infections
Complications after surgery
Infection at wound site
Leakage of urine into the abdominal cavity

Recovery from Patent Urachus

Some child surgery experts insert a type of tube called a Foley catheter before repairing a child’s urachus (the tube that connects the belly button and bladder in a fetus), while others skip this process. For the first two weeks after the operation, the child should not take baths or allow their surgical wounds to be fully submerged in water. A routine check-up is also necessary to ensure the surgical cuts are healing properly. Most children can be trusted to limit physical activities on their own, and it’s unusual for a hernia (a protrusion of an organ through the wall of the cavity it’s contained in) to develop from the incision.

Preventing Patent Urachus

Families should be informed about the causes of urachal abnormalities, or issues with the tube that connects the belly button to the bladder in unborn babies. If this condition is identified when the baby is very young, there could be other issues with the urinary system, such as problems with the tube that carries urine from the bladder out of the body (posterior urethral valves), and further investigation may be necessary.

If a baby is brought in due to a wet belly button, families should be comforted knowing that this usually means the baby has non-threatening tissue growth at the belly button (umbilical granulation tissue), which will likely go away on its own.

Children who are a confirmed case of a patent urachus (the tube did not close as it should), had a previous infection in a urachal cyst (a fluid-filled pocket), or show symptoms of a urachal polyp (a growth of tissue) or diverticulum (a pouch or sac developed), will need to have a surgery done to remove these. Families should understand what to expect during the recovery period after surgery.

For children who have urachal abnormalities discovered by chance and doctors are considering a watch-and-wait approach, it is important to be aware of the very small chance that these abnormalities could lead to cancer in the future.