Urachal remnants: fluid from the belly button

What is the urachus?

In the womb, the top of the bladder is connected to the belly button by a thin channel. This channel is called the urachus. Normally it closes before birth and turns into a firm cord. When the closure is incomplete, various urachal remnants form.

Types

• Patent urachus: an open channel remains between the belly button and the bladder, and urine comes out of the belly button.
• Urachal sinus: only the belly button end of the channel stays open, and fluid comes out of the belly button from time to time.
• Urachal cyst: the middle of the channel stays open and forms a cyst. It is often found when it becomes inflamed.
• Urachal diverticulum: a small pouch left on the bladder side. It usually causes no symptoms.

Symptoms

• constant or intermittent wetness, urine or infected fluid from the belly button,
• slow healing of the belly button, redness around it,
• a painful lump below the belly button and fever (an inflamed cyst),
• recurrent urinary tract infection.

Sometimes the remnant causes no symptoms at all and is found by chance on an ultrasound done for another reason.

Diagnosis

Ultrasound is the main test: it shows a channel or cyst extending from the belly button toward the bladder. When needed, an X-ray with contrast injected through the belly button or a VCUG (voiding cystourethrogram) can be done.

Treatment

• Remnants found by chance without symptoms, especially in babies, often resolve over time and are only monitored with ultrasound.
• An inflamed cyst is first treated with antibiotics, sometimes with drainage. After the inflammation settles, the remnant is removed in a planned operation, because the inflammation can come back.
• A patent urachus and remnants that cause symptoms are removed surgically. The operation is done through a small incision below the belly button or laparoscopically, and the corresponding part of the bladder is closed.