Draft:Umbilical-urachal sinus

Introduction

Umbilical-urachal sinus
Other names	Urachal sinus
Specialty	Urology

The umbilical-urachal sinus, also known as the urachal sinus, is a congenital anomaly resulting from the incomplete obliteration of the urachus. The urachus is a fibroelastic structure that connects the fetal bladder to the umbilicus during development. If the urachus fails to close properly, it can lead to various anomalies, including the umbilical-urachal sinus, which may present as a sinus tract or cyst at the umbilicus.

It is thought have been first described by Cabriolus in 1550.

Anatomy and Embriology

Anatomy

The urachus is a remnant structure formed during fetal development, deriving from the allantois, a part of the embryonic excretory system. It typically runs from the apex of the bladder to the umbilicus, and upon birth, it usually obliterates and transforms into the median umbilical ligament. An umbilical-urachal sinus occurs when this obliteration is incomplete, resulting in a communication between the bladder and the umbilicus.

Embriological Developement

During the 6th to 7th week of gestation, the allantois is incorporated into the developing bladder. As the fetus grows, the urachal structure normally undergoes regression. A failure in this process can lead to various urachal abnormalities, including:

• Urachal cyst (closed or fluid-filled sac)
• Urachal fistula (open connection between the bladder and umbilicus)
• Umbilical-urachal sinus (partial connection)

Symptoms

Symptoms of an umbilical-urachal sinus can vary depending on the extent of the condition and whether any complications arise. Common symptoms include:

1. Discharge from the Umbilicus:
   • This may be clear, cloudy, or purulent, often indicating infection or fluid accumulation in the sinus.
2. Umbilical Erythema:
   • Redness and inflammation around the belly button can occur, particularly if there is an infection.
3. Persistent Wet Umbilical Area:
   • The umbilical region may appear moist despite proper hygiene efforts.
4. Abdominal Pain or Discomfort:
   • In some cases, patients may experience generalized abdominal pain, particularly if there are associated urinary tract infections.
5. Urinary Symptoms:
   • Symptoms such as increased frequency, urgency, or pain during urination may occur if there is a connection to the bladder.
6. Fever:
   • If an infection develops, systemic symptoms, such as fever, may be present.
7. Foul-Smelling Discharge:
   • This may indicate an infection or necrosis of the sinus tract.

Causes

An umbilical urachal sinus primarily arises from incomplete closure of the urachus, a remnant structure that connects the bladder to the umbilical cord during fetal development. In normal circumstances, the urachus obliterates after birth, forming a fibrous cord. If this process doesn’t occur completely, various clinical anomalies, including umbilical urachal sinus, can develop. Here are some key causes and factors related to the condition.

1. Incomplete Closure of the Urachus:

•    The most direct cause of an umbilical urachal sinus is the failure of the urachus to obliterate completely after birth, leading to a sinus tract.

2. Developmental Abnormalities:

•    Certain congenital conditions affecting the urinary system may increase the likelihood of urachal anomalies.

3. Genetic Factors:

•    A family history of urachal remnants can suggest a genetic predisposition to these kinds of developmental anomalies.

4. Associated Conditions:

•    Conditions that affect other abdominal structures, such as bladder exstrophy or other urogenital malformations, can sometimes be associated with urachal anomalies,urinary tract

5. Environmental Factors:

•    While environmental factors are less clearly defined, certain influences during pregnancy may play a role in urachal development issues.

Mechanism

The pathophysiology of an umbilical urachal sinus revolves around the failure of normal obliteration of the urachus, leading to abnormal communication between the bladder and umbilicus, with potential for infection and other complications.The Umbilical urachal sinus involves the incomplete obliteration of the urachus, which is a fibrous cord that connects the fetal bladder to the umbilical cord. Here’s a detailed overview of the mechanism involved:

Normal Development of the Urachus:

1. Fetal Development:

•    The urachus is formed during embryonic development as a tube that connects the bladder to the umbilical cord, allowing for the drainage of urine from the fetus.

   2. Postnatal Obliteration:

•    After birth, the urachus typically closes and becomes a fibrous remnant known as the median umbilical ligament. This closure generally occurs within the first few weeks of life.

Pathophysiological Mechanism Leading to an Umbilical Urachal Sinus:

1. Incomplete Closure:

•    In cases of umbilical urachal sinus, the closure of the urachus does not occur completely. This can result in a patent or partially patent connection between the bladder and the umbilicus.

2. Formation of a Sinus:

•    The incomplete closure leads to the formation of a sinus tract that extends from the bladder toward the umbilicus. Depending on the degree of obliteration, this can result in an open umbilical sinus, which communicates with the bladder.

3. Potential for Infection:

•    The presence of a sinus can create a potential pathway for urinary tract bacteria to reach the surface of the skin around the umbilicus, leading to infection and inflammation. This often manifests as discharge from the umbilicus, which may be clear, cloudy, or purulent in nature.

4. Epithelialization:

•    The lining of the sinus may become re-epithelialized, leading to changes in the types of cells present in the sinus tract, which can complicate further management.

5. Complications:

•     If left untreated, the sinus can lead to chronic infections, performative abscesses, or can even provide a pathway for the development of more complex issues like urachal cysts, diverticula, or urachal cancer, although the latter is rare.

Diagnosis

Diagnosis of an umbilical-urachal sinus usually involves clinical examination and imaging techniques.

Common diagnostic steps include:

• Physical Examination: Inspection of the umbilical region may reveal signs of infection or discharge.

• Ultrasound: An abdominal ultrasound can help visualize any abnormalities in the urachal remnant.

• CT or MRI: These imaging techniques may be utilized to delineate the anatomy of the sinus and assess for associated complications.

Complications

• Infection, with possible abscess formation.
• Concurrent occurrence of a tumour.
• Development of a urachal cyst
• Potential for malignancy in advanced cases (though rare)

Treatment

The primary treatment for an umbilical-urachal sinus is surgical intervention. Excision of the sinus tract is generally performed to prevent recurrent infections and complications. The surgical procedure entails removing the sinus and ensuring complete closure of any communication with the bladder.

Prospective care

• Patients require careful monitoring for signs of infection or complications following surgical repair.

• Proper wound care, follow-up appointments, and patient education regarding signs of infection are vital for recovery.

Prognosis

The prognosis for patients with an umbilical-urachal sinus is generally good with appropriate surgical treatment. Excision of the sinus usually prevents recurrence and minimizes the risk of complications. Early diagnosis and intervention are key to preventing chronic infection and potential complications.

Epidemology

Umbilical-urachal sinus is a rare condition, occurring more frequently in males than females. It is most commonly diagnosed in children, although cases in adults are occasionally reported.

See also

• Urachus
• Patent urachus
• Urachal cyst
• Urachal diverticulum

References

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Category:Congenital disorders of urinary system