Patent Urachus

Overview

The urachus is a small tube that connects the bladder to the navel (belly button) while a baby is developing in the womb. Normally, before or shortly after birth, this channel closes and shrinks into a thin cord of tissue. A patent urachus occurs when the channel fails to close completely and remains open along its full length, leaving a passage between the bladder and the surface of the abdomen at the navel.

This is a rare congenital condition, usually identified in newborns or young infants. Because the open channel connects directly to the bladder, urine can leak out through the belly button. Patent urachus is one of several urachal anomalies; related problems include a urachal cyst or sinus, where only part of the channel stays open. With diagnosis and treatment, the outlook is generally very good.

Symptoms

The most noticeable sign is fluid coming from the belly button. Features that suggest a patent urachus include:

• Clear or urine-like fluid leaking from the navel, sometimes increasing when the baby strains or cries.
• A constantly moist or wet belly button that does not heal as expected after the umbilical cord falls off.
• Skin irritation or redness around the navel from constant moisture.
• Signs of infection such as foul-smelling discharge, swelling, warmth, fever, or pus if the channel becomes infected.

In some cases the leakage is subtle and the problem is suspected only when the umbilical area fails to dry and heal normally.

Causes

A patent urachus is caused by incomplete closure of the urachus during fetal development. In normal development, the urachus is needed early in pregnancy and then closes off, becoming a fibrous cord. When this closure does not happen fully, the open channel persists after birth.

The exact reason the channel fails to close is not known, and in most cases it occurs by chance rather than being inherited. It is not caused by anything the parents did during pregnancy. In some infants, a urachal problem is associated with other conditions that increase pressure in the bladder, but most cases occur on their own without a clear underlying cause.

Risk Factors

• Being a newborn or young infant, when most cases are discovered
• Other anomalies of the urinary tract in some cases
• Conditions that raise bladder pressure or block bladder outflow, which can keep the channel open

Patent urachus is rare and, in the great majority of cases, occurs without any identifiable risk factor or family history.

Diagnosis

Diagnosis begins with examining the belly button and the leaking fluid. Tests used to confirm the condition include:

• Ultrasound: A safe, painless imaging test that can show the channel between the bladder and navel.
• Fluid analysis: Testing the leaking fluid to confirm that it is urine.
• Contrast studies: Imaging in which dye is used to outline the open channel and show its connection to the bladder.
• Examination for infection: If redness, swelling, or discharge suggests infection, additional evaluation may be needed.

Treatment

Treatment usually involves surgery to remove the persistent channel:

• Surgical excision: The open urachus is removed and the bladder is closed, which corrects the leakage and prevents future problems such as infection.
• Minimally invasive surgery: In many cases this can be done through small incisions.
• Treating infection first: If the channel is infected, antibiotics and sometimes drainage are used before definitive surgery.

Removal also addresses a long-term concern: persistent urachal tissue carries a small risk of problems later in life, so complete removal is generally recommended. Most children do very well after treatment with normal bladder function.

Prevention

Patent urachus is a congenital condition that develops before birth, so it cannot be prevented. There is nothing parents can do during pregnancy to cause or avoid it. The focus is on early recognition and treatment rather than prevention.

• Watch for fluid leaking from a newborn's belly button or a navel that stays wet and does not heal
• Keep the umbilical area clean and dry while awaiting evaluation
• Seek medical advice promptly if leakage, redness, or signs of infection appear

When to See a Doctor

Contact your child's doctor if you notice fluid leaking from the belly button, a navel that stays moist and does not heal after the umbilical cord falls off, or persistent irritation of the surrounding skin. Seek prompt care if there are signs of infection, such as:

• Redness, swelling, or warmth around the navel
• Foul-smelling discharge or pus
• Fever or a child who seems unwell

Early evaluation allows accurate diagnosis and timely treatment.

Related Topics

Frequently Asked Questions

References

1. MedlinePlus, U.S. National Library of Medicine. Urachal anomalies.
2. Mayo Clinic. Birth defects — Symptoms and causes.
3. American Urological Association. Congenital urinary tract anomalies.
4. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Urologic Diseases.