What are urachal abnormalities?
Developing fetuses have a canal between the belly button and the bladder known as the urachus. This typically closes before birth. Sometimes, however, that doesn't happen, and a baby will be born with the canal still in place. Problems related to this are known as urachal abnormalities, and are rare. They are more common in boys than girls.
Symptoms and Causes
What symptoms do urachal abnormalities cause?
In babies, parents might notice persistent wetness around the belly button. This most often is a granuloma, which is an area that is red and irritated because the umbilical cord stump didn't heal correctly. If the area stays red after the stump comes off, dabbing a small amount of hydrogen peroxide on the site twice a day may help it heal. If the redness doesn't go away or gets worse, you should talk to your child’s doctor.
When the wetness is more extreme, it may be because there is an opening, or sinus, from the bladder to the belly button from which urine is leaking. When this happens, it's called a patent urachus.
Urachal abnormalities are much less common in older children or adults. These often take the forms of lumps, or cysts, which can become infected. This happens because the two ends of the canal have closed, but an open central portion in which fluid gathers still remains. Problems related to this include lower belly pain, fever, pain on urination, a urinary tract infection or blood in the urine.
Other problems that are sometimes seen with urachal abnormalities include infections of blood vessels that are part of the urachus or problems with the vitelline duct, which is between the belly button and the small intestine.
Diagnosis and Tests
How are urachal abnormalities diagnosed?
If a doctor sees anything on a physical exam that makes them think a patient might have a urachal problem, they will send the patient for an ultrasound. This painless and noninvasive test allows doctors to see internal tissues and organs. For some patients, a magnetic resonance image (MRI) may be needed as well. An MRI is also a painless way to take images inside your body.
If your doctor suspects that wetness near the belly button is really urine coming from the bladder, they can test the fluid to see if it contains urea or creatinine, both of which are present in urine. If this is positive, the doctor will likely order a sinogram, a test in which a small tube is placed through the belly button opening, dye is injected and X-rays are taken. If the dye is seen to be moving from the belly button to the top of the bladder, that usually means the presence of a urachal sinus.
Other tests that can be used to provide a clear view of the tissue behind the belly button include voiding cystourethrogram, sometimes called a VCUG. In a VCUG dye is injected through the urinary tract into the bladder. This is particularly useful when there's also a problem with the structure of the bladder.
Management and Treatment
How are urachal abnormalities treated?
For patients with persistent wetness around the belly button area, the doctor can usually do a chemical cauterization, which involves putting a small amount of a chemical around the area. This usually helps it heal up within days. Sometimes the doctor will have the patient take antibiotics afterward as a precaution.
For patients who have fluid-filled cysts in the area of the urachus, antibiotics are usually very effective. Some patients also will need to have the fluid drained with a needle.
After that has healed, most patients will need surgery to remove the urachus and anything connected to it, such as the top of the bladder. Leaving urachal tissue behind increases a patient’s risk of developing cancer.
Outlook / Prognosis
What is the long-term outlook after surgery for urachal abnormalities?
Most patients who have surgical removal do well and do not have any further problems.
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