Urachal Fistula - Symptoms, Causes, Treatment & Prevention

Urachal fistulas are rare congenital anomalies. Population‑based studies estimate an incidence of about 1 in 5,000 to 1 in 10,000 live births (Miller et al., *J Pediatr Surg* 2020). They are diagnosed most often in infancy, but a small percentage present later in childhood or adulthood when the tract becomes symptomatic.

Both males and females can be affected, though a slight male predominance (≈ 55 %) has been reported. Because the condition originates in utero, there is no link to lifestyle or environmental exposures.

Symptoms

The clinical picture varies with the size of the tract, the amount of urine that passes through it, and whether infection has developed. Commonly reported signs include:

• Umbilical discharge – clear, yellow‑white, or urine‑stained fluid that may become foul‑smelling.
• Wet or moist umbilicus – persistent dampness that does not improve with hygiene.
• Recurrent umbilical infections (omphalitis) – redness, swelling, tenderness, and possible pus formation.
• Foul‑smelling urine from the belly button – especially when the infant voids.
• Lower abdominal pain or cramping – can be intermittent and may mimic urinary tract infection.
• Fever – a sign of secondary infection.
• Urinary frequency or urgency – rare, seen when the fistula diverts a significant volume of urine.
• Palpable midline mass – sometimes a cystic swelling adjacent to the umbilicus.
• Hematuria – blood in the urine if the fistula becomes inflamed.
• Abdominal distension – in severe cases with associated urinary obstruction.

Adults who present with a urachal fistula often report a long‑standing “wet belly button” that suddenly becomes painful or infected, prompting medical evaluation.

Causes and Risk Factors

Embryology

The urachus is a remnant of the allantois, a canal that drains fetal urine into the amniotic sac. Normally, by the 12th–16th week of gestation, the lumen obliterates and the structure fibroses. Failure of this involution can result in four anatomic patterns:

1. Patent urachus (complete fistula) – the most severe form.
2. Urachal cyst – both ends closed, fluid‑filled cavity in the midline.
3. Urachal sinus – opens at the umbilicus but closed toward the bladder.
4. Urachal diverticulum – opens toward the bladder but closed at the umbilicus.

A patent urachus is the only type that creates a true fistulous tract.

Risk Factors

• Male sex – modestly higher incidence.
• Prematurity – some series show a slightly increased risk in preterm infants.
• Family history of urachal anomalies – rare but reported.
• Associated congenital anomalies – such as bladder exstrophy or omphalocele, may coexist.

There are no known environmental, dietary, or occupational risk factors.

Diagnosis

Because the presenting sign is often a persistent umbilical discharge, the first step is a careful physical examination.

Clinical Evaluation

• Inspection of the umbilicus for wetness, drainage, or erythema.
• Gentle probing with a sterile cotton swab – may reveal urine‑like fluid.
• Assessment of growth parameters and signs of infection (fever, tachycardia).

Laboratory Tests

• Urinalysis of the discharge – testing for urea, creatinine, and specific gravity confirms that the fluid is urine.
• Complete blood count (CBC) – to evaluate for leukocytosis if infection is suspected.
• Blood cultures – in cases with systemic signs of infection.

Imaging Studies

1. Ultrasound (US) – first‑line, non‑invasive tool that can visualize a tubular tract extending from the bladder to the umbilicus and detect associated cysts or abscesses.
2. Fistulography – injection of contrast into the umbilical opening followed by fluoroscopy; provides a clear map of the tract.
3. Computed Tomography (CT) Scan – especially with contrast, useful for pre‑operative planning and to rule out malignancy in adults.
4. MRI – offers excellent soft‑tissue contrast without radiation; preferred in children when detailed anatomy is needed.

Differential Diagnosis

Other conditions that can mimic a urachal fistula include umbilical granuloma, ventral hernia, omphalitis, and infected epidermoid cysts. Imaging helps to distinguish these entities.

Treatment Options

Because a patent urachus creates a pathway for urine and bacteria to the skin, definitive treatment is surgical. Medical management alone is generally insufficient except as a bridge to surgery.

Initial Medical Management

• Antibiotics – Empiric broad‑spectrum agents (e.g., amoxicillin‑clavulanate or cefazolin) are started if infection is present. Tailor to culture results.
• Pain control – Acetaminophen or ibuprofen for mild‑to‑moderate pain; stronger analgesics if necessary.
• Skin care – Keep the area clean and dry; use sterile gauze to protect against maceration.

Surgical Techniques

1. Open Excision – Traditional method; a transverse or vertical infra‑umbilical incision allows complete removal of the urachal tract up to the bladder dome. The bladder is closed in two layers.
2. Laparoscopic Excision – Minimally invasive; three small ports provide visualization and allow precise dissection. Advantages include less postoperative pain, shorter hospital stay, and better cosmetic results. Systematic review (Kumar et al., *Surg Endosc* 2021) reported a 95 % success rate with a mean stay of 1.5 days.
3. Robotic‑assisted Excision – Emerging technique offering enhanced dexterity, especially for complex or large tracts; outcomes comparable to laparoscopy.

All approaches aim for complete excision of the tract and a primary closure of the bladder wall to prevent recurrence.

Post‑operative Care

• Indwelling urinary catheter for 24‑48 hours to keep the bladder decompressed.
• Continuation of prophylactic antibiotics for 24‑48 hours (longer if infection persisted).
• Analgesia as needed and wound care instructions.
• Follow‑up ultrasound at 4‑6 weeks to confirm healing.

Potential Role of Conservative Management

In extremely low‑weight infants or patients unfit for surgery, a temporary “watch‑and‑wait” approach with meticulous hygiene and antibiotics may be employed, but definitive surgery is recommended once the child is medically stable.

Living with Urachal Fistula

Even after successful surgery, families benefit from practical strategies to promote healing and prevent complications.

• Wound hygiene – Change dressings daily, keep the area dry, and avoid tight clothing that could irritate the incision.
• Hydration – Adequate fluid intake supports normal urine production and helps flush the urinary tract.
• Bladder habits – Encourage regular voiding; avoid prolonged holding of urine.
• Monitor for recurrence – Any new wetness, discharge, or pain at the umbilicus should be reported.
• School and daycare – Children can return once the incision is fully healed and no fever is present (usually 7‑10 days post‑op).
• Psychosocial support – Some children may feel self‑conscious about a scar; reassure them and consider a scar‑care regimen (silicone gel sheets or ointment).

Prevention

Because a urachal fistula is a congenital defect, primary prevention is not possible. However, early detection and timely treatment can prevent complications:

1. Neonatal screening – Routine newborn examinations should include inspection of the umbilical stump for persistent drainage.
2. Prompt medical attention for any umbilical wetness lasting beyond the first 2 weeks of life.
3. Maternal prenatal care – While it does not prevent the anomaly, high‑quality prenatal ultrasound may identify urachal cysts or other midline anomalies, allowing early counseling.

Complications

If left untreated, a urachal fistula can lead to serious problems:

• Recurrent Omphalitis – Chronic infection can spread to the fascia and cause cellulitis.
• Abscess formation – Pocket of pus may develop along the tract, requiring drainage.
• Urosepsis – Bacterial entry into the bloodstream from the infected fistula can be life‑threatening, especially in infants.
• Urolithiasis – Stagnant urine in the tract predisposes to stone formation.
• Urachal carcinoma – Although rare (<0.01 % of all bladder cancers), malignant transformation of a long‑standing urachal remnant can occur, typically in adults aged 40‑60 (WHO, 2022).

When to Seek Emergency Care

References

1. Miller JM, et al. “Incidence and presentation of urachal anomalies in newborns.” Journal of Pediatric Surgery. 2020;55(4):754‑759.
2. Kumar R, et al. “Laparoscopic versus open excision of urachal remnants: a systematic review.” Surgical Endoscopy. 2021;35(6):2581‑2590.
3. National Institutes of Health. “Urachal Anomalies.” NIH. Accessed June 2024.
4. World Health Organization. “Rare Tumors of the Urinary Tract.” WHO Classification, 2022.
5. Cleveland Clinic. “Urachal Fistula – Symptoms, Diagnosis, and Treatment.” Updated 2023. clevelandclinic.org.