A Case of Patent Urachus - The Horse Owner's Resource

A Case of Patent Urachus

A newborn foal urinating from a hole in his abdomen looks frightening, but the situation isn't as dire as it seems.
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All seemed well at first when a retired cutting horse named Ashez delivered a handsome sorrel colt at Ranch One in Batesville, Mississippi. After an uneventful labor, the foal slipped onto the straw at 4:30 a.m. on March 4, 2013.

Signs of patent urachus are typically seen within hours of a foal's birth. ©EQUUS Magazine

Signs of patent urachus are typically seen within hours of a foal's birth. ©EQUUS Magazine

"He was absolutely gorgeous, just a phenomenal colt," recalls Kerri Carriere, Ranch One's breeding manager. As always, Carriere kept meticulous notes, and she recorded that the foal stood for the first time at 4:55 a.m. "[He was] an average-size foal, but stunning to look at," she says. "He had a big bold blaze down the front of his face, and he was just beautiful."

Soon, however, Carriere noticed something she'd never seen before: "As soon as the umbilical cord broke, I dipped his navel [area] into the antiseptic, but it didn't look normal. Usually when the umbilical cord breaks there is the loose skin on the outside and the solid cord in the middle. But this time there was a hole in the middle of the cord. While I knew it didn't look right, I didn't know for sure what---if anything---was really wrong. I decided to give him a few minutes, then I came back to look again. I think I was hoping each time I looked that it would change."

Meanwhile, the colt went about his baby business. He wobbled around his stall, flicked his downy tail, nursed his dam and sized up the barn staff, who gave him the barn name Travis. Ashez accepted with equanimity the ministrations of the ?people helping her with Travis, her third foal. In fact, neither mare nor colt seemed to have a care in the world.

Carriere, however, had many concerns. Too worried to leave the barn that morning, she continued to monitor the foal and ponder the unusual umbilical cord. Because Travis was bright-eyed, alert, moving about, nursing well and otherwise acting like a healthy newborn, she felt watchful waiting was her best course.

Wide open
Carriere's misgivings grew into outright fear later that morning, just before 11 a.m., when Travis urinated for the first time. He stood, and a full stream of urine poured forth---not from his penis, but from the underside of his belly. Moving in to take a closer look, Carriere discovered that the foal had a hole in his abdomen, as wide as a quarter, where the umbilical cord stump had dropped away just a few hours earlier. Urine was flowing freely from the hole.

Carriere was worried. "Had his umbilical cord or his bladder been torn during the birth?" she wondered. "Would he be OK?"

Then another fear loomed: The colt had been lying in the stall---the opening in his abdomen had been in direct contact with the bedding. "Infection was the next horrible thing that ran through my mind, because that area is wide open to his internal organs," says Carriere. "You could have stuck your finger up to the second knuckle into that hole, way up into his abdominal cavity."

Carriere phoned Steve Shideler, DVM: "He couldn't even understand me I was talking so fast, I was so upset," she recalls. "He told me to slow down and please just calm down so he could understand what was going on."

Once he grasped the situation, Shideler explained that the foal most likely had a patent urachus---a term derived from the Latin word "patere," which means "to lay open," and urachus, which is a channel that connects the urinary bladder to the umbilicus (navel) during fetal development.

While the fetus is in the womb, its urine drains via the urachus, out through a tube contained within the umbilical cord and into the sac of fluid that surrounds it. Normally, at birth, after the umbilical cord ruptures the urachus begins to shrink. Within a few hours, it should close at the navel, and then the foal's bladder begins to empty via the urethra. Sometimes, however, the urachus does not close completely, and urine may continue to trickle or even flow from the hole where the umbilical cord had been. That was the case with Travis.

The cause of patent urachus is still unknown, but some factors are thought to contribute, including infection at the umbilicus, increased abdominal pressure during foaling, an unusually long umbilical cord or twisting of the umbilical cord that causes stress at the fetal navel. Foals born sick or debilitated are more likely to be affected. Any mammal can develop patent urachus, but precocious animals like horses are more prone to it because they have to stand on their own and run within hours, which can put strain on the area and prevent closure. Sometimes, if the foal is lifted by the abdomen or struggles with constipation, a urachus that had closed just after birth can reopen; systemic infection can also cause a urachus to reopen.

The good news was that patent urachus is usually not a life-threatening condition. Shideler told Carriere he would stop by to examine Travis later that day. Until then, he advised her to keep the foal's umbilical area clean and call him immediately if Travis's condition deteriorated. Carriere continued her stall-side vigil.

Watch and wait
Shideler arrived to find a young colt with a plush coat, big dark eyes, pole-like legs---and a hole in his belly. Docile and friendly, Travis took the examination in stride. Shideler's assessment confirmed the foal did indeed have patent urachus.

The best-case and most likely scenario, Shideler told Carriere, was that the opening in Travis's abdomen would close on its own within the next day or two. If it didn't, they could discuss treatment options. Sometimes, a caustic agent like silver nitrate might be applied to the opening, to help stimulate scar tissue that would close it up. Surgery, while an option, probably wouldn't be necessary.

Shideler also warned that, as Carriere had suspected, the opening at the navel would have to be kept scrupulously clean. A bacterial infection at the site could easily enter the bloodstream and spread throughout the foal's body. That complication could be fatal. Travis would need to be closely monitored
until the urachus closed.

The veterinarian left Carriere with instructions to gently apply iodine solution to the opening as needed to keep it clean. Urine would continue to flow from the hole until it closed; if the foal's skin became irritated by the urine she could apply a barrier ointment to protect it. Chances were, Shideler said, the patent urachus wouldn't require surgery, and it wouldn't affect Travis's future.

While reassured by the veterinarian's assessment, Carriere fretted about the frisky foal. "I stayed with him all day, and slept outside his stall that night," she says. "I was so worried about him." But, just as Shideler had predicted, the hole began to close on its own within hours, and the urine stream slowed to a trickle. By midnight, there was no urine at all coming from the hole.

It's not a milestone most people cherish, but Carriere was thrilled and delighted the first time she saw Travis stretch out and urinate normally from his penis. "The actual treatment wasn't that hard," she says, "but all that worrying was the worst." When Shideler returned the next day, he confirmed that the hole had closed and that there would be no need for further treatment or referral to a surgical facility.

Alison Eddy, DVM, DACVS, of Mississippi State University, sees several referral cases of patent urachus each year: "There are basically two types: the straightforward patent urachus that closes spontaneously or is treated with cautery and antibiotics by the local veterinarian. Then there are the foals with a patent urachus that initially closed at birth but reopened. These can be more ominous and difficult to treat, since the urachus may have reopened because of infection. That infection could have originated in the lungs or the GI tract, and it can also spread to the joints. This can be life-threatening. Some of these foals respond well to medical treatment, but some of them will need surgery to remove the infected tissue and to close the urachus."

To minimize the risk of reopening a urachus, Eddy suggests that people "avoid pulling on the umbilical cord or vigorously restraining a newborn foal." It's best to allow a newborn's umbilicus to break on its own. However, as Travis's case shows, sometimes everything can go exactly right, and this abnormality can still occur.

Today, Travis is a healthy, happy foal who shows no ill effects from his experience. In fact, if anything, the events of his first 24 hours may have made him more people-oriented than his peers. A visitor cannot pass Travis's stall without him tapping on the wall to get attention or ask for a head rub. When out romping in the pasture, Travis will leave his dam to come greet visitors. His handlers at Ranch One have high hopes for his future as a great cutting horse.

"We dream of Travis as a future super-star," says Carriere. "He has cutting blood on both sides, and he will playfully chase the dog down and practice herding her about in the pasture. He just has that herding instinct. He's quite a character."

In focus: Patent Urachus

Definition: condition in which the urachus, the tube that drains urine from the unborn foal's bladder into the amniotic sac, remains open after birth. There are two forms: A persistent urachus occurs when the urachus fails to close; a patent urachus is one that closes but then reopens. In common practice, however, the term "patent urachus" is used interchangeably to refer to either of these two forms.

Causes: Usually unknown, although several risk factors seem to be associated with patent urachus, including conditions in the womb that place stress on the umbilicus. A closed urachus may reopen if a foal strains with constipation, is handled in a manner that stresses his abdomen or develops an infection. Experts don't believe any breed or sex is more predisposed to the condition.

Signs: Urine may be seen dribbling or flowing in a full stream from the navel.

Diagnosis: Observation of urine emerging from the navel confirms the diagnosis, but ultrasound may be used to assess the extent of the opening and to check for signs of infection. Blood may be drawn for laboratory assessment of infection. Any moisture felt around a foal's umbilicus should be investigated to determine the source; wear exam gloves to avoid transferring bacteria to the foal. A foal's umbilical area should be checked daily to ensure it is shrinking and dryTreatment: A patent urachus usually closes spontaneously; prevention of infection is integral to complete closure and permanent healing. Because a patent urachus provides an open pathway to the internal organs, infection at the site can be deadly. If the patent urachus persists, a cauterizing or burning agent like silver nitrate may be applied. In exceptional cases, surgery to close the opening may be required; the prognosis is often good. An equine specialist must perform the surgery, which requires general anesthesia, under sterile conditions.

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