Urachal Cyst - An Overview

Introduction

Urine from the developing baby (fetus) drains through a channel between the bladder and the umbilicus (belly button) during the first trimester of pregnancy. The remnants or remains of this channel are called the urachus. The channel commonly seals off and is wiped out around the 12th week of gestation leaving behind a small fibrous cord between the bladder and the belly button called the median umbilical ligament.

What Are the Abnormalities of the Urachus?

Abnormalities in the urachus develop when there is an issue in the closing off of the channel between the bladder and the umbilicus. The most common disorders of the urachus are:

• Urachal Cyst: Urachal cyst occurs when a portion of the urachus is not sealed completely but there is no connection between the bladder and the umbilicus. Mostly, this does not cause any symptoms after birth and can be diagnosed only while taking an ultrasound for other conditions.

In rare cases, the urachus can become infected leading to abdominal pain and there can be a leakage of a cloudy or bloody fluid at the level of the umbilicus. Infection can manifest between two to four years of age.

• Patent Urachus: When the channel of urachus is not sealed and if the connection between the bladder and the umbilicus is intact, the condition is called patent urachus. This can cause different amounts of urine to be leaked at the umbilicus.

• Urachal Sinus: When the channel of the urachus near the umbilicus is not closed, a blind tract from the umbilicus ending into the urachus can be formed which is called a sinus. The person may not experience any symptoms or can develop an infection that causes abdominal pain and fluid leakage.

• Diverticulum: When the channel of the urachus near the bladder is not closed, a blind tract from the bladder ending into the umbilicus can be formed which is called a diverticulum. The person may not experience any symptoms or can develop a urinary tract infection.

What Are the Symptoms Associated With Urachal Cyst?

The symptoms of a urachal cyst occur only when there is an infection. These symptoms are:

• Distended abdomen or rigidity.

• Abdominal pain.

• Abdominal masses that can be felt.

• Pelvic (hip) pain.

• Chills.

• Fever.

• Pain during urination.

• Presence of blood in the urine (hematuria).

• Cellulitis of the abdominal wall (bacterial infection in the abdominal wall).

• Frequent occurrence of urinary tract infections.

In severe cases of infection, there can be redness and swelling in the abdomen, vomiting, severe abdominal pain, peritonitis (inflammation of the lining of the membrane in the abdominal wall and covering of the abdominal organs), and extreme fatigue.

Does Urine Come Out of the Belly Button in Urachal Cysts?

The drainage of urine from the belly button is rare. Urine can drain from the belly button of newborns if there is a problem in the closure of the channel near the umbilicus called the urachal sinus. Due to this, the healing of the umbilical cord after birth is poor. The belly button can be persistently moist in case the urine drains from the belly button of urachal cysts. If this is not cleaned repeatedly, the skin can become red with a foul odor.

Are Urachal Abnormalities Common?

Urachal abnormalities are rare. They are detected only during imaging for other conditions or in autopsies (a procedure in which a corpse is examined by dissection). Urachal abnormalities are more common in men than in women. The cause for these abnormalities is unknown. Urachal cysts can occur if the urachal area is partially developed. Since these abnormalities occur at birth (congenital), there can be genetic reasons for their occurrence.

How Are Urachal Cysts Diagnosed?

The healthcare professional will ask for the medical history, carry out a physical examination and suggest laboratory tests before proceeding with the treatment. Confirmation of urachal cysts is done through:

• Ultrasounds.

• Computed tomography (CT).

• Magnetic resonance imaging (MRI).

• Sinogram or sinography (a contrast is introduced into the umbilicus to determine if it is a urachal sinus or a patent urachus).

• Voiding cystourethrogram (VCUG-to detect urinary tract infection or to ensure the proper drainage of the bladder).

• Fistulography (an X-ray technique to view the abnormal passage between two or more parts of the body that drains out of the skin called a fistula).

Imaging techniques enable the doctor to confirm the presence of the cyst and to find out if it poses a problem.

What Is the Differential Diagnosis for Urachal Cysts?

Urachal cysts can resemble many conditions:

• A urinary tract infection.

• Cellulitis (a common and serious bacterial infection).

• Pelvic inflammatory disease (infection of a female’s reproductive organs).

• Inflammatory bowel disease (long-standing infection of the gastrointestinal tract).

• Appendicitis (inflammation of the appendix) without rupture.

• An intra-abdominal abscess (collection of infected fluid or pus which is surrounded by inflamed tissue inside the abdomen).

• Omphalitis (inflammation of the umbilicus particularly in newborns).

• Bowel perforation (a hole in the large intestine that causes stool to leak into the abdomen).

• Strangulated umbilical hernia (a life-threatening medical condition in which the blood supply to the herniated tissue is cut off).

How Is Urachal Cyst Treated?

The treatment depends on the status of the cyst and the presence of complications like peritonitis or rupture. An uninfected cyst does not require any treatment. Most of the infected cases can be treated with oral antibiotics. The other treatment modalities are:

• Administration of antibiotics. Severe infected cases may require antibiotics administered through the intravenous route.

• Drainage.

• Surgical removal of the cyst.

Any one of the above or all the above treatment options may be implemented based on the condition of the cyst. The Urology Care Foundation (UCF) recommends that all the urachal remnants or remains be completely removed through surgery. The UCF does not suggest the removal of urachal abnormalities through a needle as there has been a recurrence in one-third of the patients. Since there is a risk of post-surgical infection, oral antibiotics are given to the patients before the surgical procedure. Surgical options include:

• Laparoscopy (a surgical procedure using a fiber-optic instrument that is inserted through the abdominal wall to view the abdominal organs and perform the surgery).

• Through robots.

• Open abdominal surgery.

What Are the Complications of Urachal Cysts?

The majority of people with urachal cysts are asymptomatic but 35 % of the individuals with urachal cysts can experience painful symptoms that require medical attention. The complications of urachal cysts are:

• Infections are due to the collection of materials within the cyst that encourages the growth of bacteria like Escherichia coli (E. coli) and Staphylococcus aureus. Infected cysts can leak, and the contents can enter the abdominal cavity.

• In a few instances, the urachal cysts can rupture. These may drain into the bladder and can resemble urinary tract infections (UTIs).

• Enteric fistula (a life-threatening condition in which an abnormal connection is formed between the urachal cyst and the adjacent organs).

• Can develop into peritonitis (abdominal infection).

• Sometimes, urachal cysts may enlarge causing symptoms but do not rupture.

• Incomplete removal of the urachal cyst can cause a type of bladder cancer called urachal cancer. Urachal cancer constitutes less than 1% of bladder cancers.

Conclusion

Urachal cyst occurs if the connection between the bladder and the umbilicus is not sealed before birth. Most people with urachal cysts lead a normal life without any symptoms. Infection of the cyst may require medical help. Surgery is needed if there is excess drainage, discomfort, irritation, or repeated infection of the cyst and to reduce the risk of future complications. Very rarely, a urachal cyst can develop into urachal cancer.