The evening pediatric clinic was winding down, and the note on the next chart said, “One week old, belly button problem.” Good, I thought, this case should be straightforward. New parents are usually concerned about one of three things when it comes to their newborn’s belly button: the normal whitish inflammatory material at the base of the cord, which makes it look as if there is an infection; slight bleeding that can happen when the cord falls off; or an unhealed stump of umbilical cord called a granuloma, which must sometimes be treated with a topical chemical that cauterizes the tissue.
I introduced myself to the parents, who looked worried and more than a little tired. With a newborn at home, that was not surprising. The baby, dressed in a pink sleeper, was asleep, but she quickly woke up when her mother began to undo the snaps.
“It looks like her belly button is infected,” the mother said. OK, I thought, anticipating a quick, reassuring talk. But when she lifted up the infant’s undergarment, I stopped short. The baby’s cord had already fallen off, so the parents weren’t worried about the normal discharge around the cord stump. Something else was wrong.
I recalled a baby I’d seen during a stint in the neonatal intensive care unit during my pediatric residency. What had appeared to be a small infection of the umbilicus proved to be a serious infection known as omphalitis. That baby had died.
To small children, the belly button, also known as the navel or umbilicus, is one of the great mysteries of life. My parents told me it was “the knot that the doctor tied in the cord when you were born.” Some cultures endow it with a mystical significance. In Greece, for example, the word for navel, omphalos, is also used to refer to the center of the world. Hawaiians use the word piko for both the umbilical cord and the navel; it is said to be the gate connecting a baby to its ancestors.
That link is literally true—for one generation, at least. The umbilical cord connects the fetus to the placenta, the structure that attaches to the mother’s uterus and funnels nutrients to the fetus. After the baby is born, doctors clamp the cord and cut it, leaving a remnant two to three inches long. The mother delivers the placenta, with the rest of the cord attached, afterward. That is why the placenta is also called the afterbirth.
Over the next few days, the baby’s cord dries out. Protective white blood cells congregate around the base, forming the puslike material that sometimes alarms parents. Enzymes produced by the white cells gradually dissolve the connection at the base of the cord, until one day it just falls off. After a day or so, the small, flat stump that remains is covered by fibrous scar tissue. Eventually, skin grows over the area, and it then becomes the belly button we all know. (Most people have an inward, contracted belly button. Those that poke outward are usually related to small defects in the abdominal wall.)
But when I looked at this baby’s umbilicus, I saw a small amount of pus around the area where the cord had detached. I swabbed the area with alcohol—and saw something I didn’t expect. In the center of the cord’s pink stump was a small dark opening, about one millimeter across, like a tiny tunnel diving into the middle of the baby’s umbilicus. That was odd. Then I saw something even more disturbing: A drop of thin yellowish-white pus exuded from that little tunnel. This was a sign of a potentially deadly problem.
There is a little-known structure in the developing fetus called the urachus, which is a tube leading from the bladder to the umbilicus. The urachus is derived from a tubelike embryonic structure known as the allantois (Greek for “sausage”), which eventually forms the urethra, the urinary bladder, and part of the umbilical cord itself. By the time most babies are born, the urachus has collapsed down to a solid cord that connects the bladder with the back of the belly button and is useful only as a landmark for surgeons.
In rare cases, however, part or all of the urachus remains open after a baby is born. When the entire tube is open, the baby will leak small amounts of urine from his belly button. Partial closure can lead to a urachal sinus, a small pocket that remains at the upper end of the urachus and still maintains its connection to the cord. Sometimes that structure can become infected. A simple infected urachal sinus is treated with oral antibiotics and removed surgically after the infection clears. I suspected that was what I was dealing with.
When I described the condition to the pediatric surgeon, she agreed that a urachal sinus was likely and advised me to start antibiotics, order an ultrasound exam of the abdomen—which would detect any cystic dilation of the urachal tract—and schedule the baby for an appointment with her the following week. “And you know what to tell the parents to watch for,” she concluded.
“Right,” I said. “I remember seeing one case of omphalitis when I was a resident. It was awful.”
Omphalitis is the most frightening complication of an infected umbilicus or urachal sinus. Bacteria that colonize the cord can sometimes overwhelm the newborn’s immature immune system. Infection in a tiny area can then quickly spread to the loose, soft tissue around the cord and rapidly enter the baby’s bloodstream. The telltale sign is swelling and redness of the skin around the cord, which often leaks pus. Suddenly, the baby begins to look sick. Those infants, like my patient years ago, can die. The condition is extremely rare in the United States, but it has been a common cause of death in the past; it is still a problem in Africa and developing countries.
Fortunately, this child didn’t look sick, and I hadn’t seen any redness around her umbilicus. After talking with the surgeon, I went back and explained the plan to the parents, outlining what they should watch for. “Make sure to bring her in right away if she runs a fever, if she won’t nurse, or if she seems very lethargic or fussy. And especially if you see the skin around the belly button turning red,” I said.
The baby’s father pointed to his daughter’s small abdomen. “You mean like that?” he said. Around the umbilicus there was a faint tinge of red, which hadn’t been there just 30 minutes earlier.
This baby wasn’t going home.
I told the hospital’s admitting pediatrician that a newborn with early omphalitis needed immediate treatment with intravenous antibiotics, along with very careful monitoring. Fortunately, we had caught the infection in time, and the baby made a full recovery. I shudder to think what might have happened if the infection had gone unnoticed just a little bit longer.
