Jacob Dylan Roddy has spent 10 of his 18 months in the hospital, fighting infections. When other kids his age are busy exploring the world, he spends most of his time on a much shorter leash, tethered to the bag of food that provides most of his nutrition.
Though he's not as active as most kids his age, Jacob is in a race.
He has short bowel syndrome, the result of a congenital problem, according to his mother, Alisha Roddy. And a small bowel transplant offers him the best chance at a normal, healthy life and perhaps even survival.
There's a lot most people don't know about their digestive system, according to Jacob's physician, gastroenterologist Dr. Daniel Jackson of Primary Children's Medical Center. Alisha Roddy knows a lot now, but she had to learn it.
For instance, people can live without their large intestine. The small intestine is more central to survival, Jackson said.
The small intestine has three parts. The duodenum connects to the stomach and is integrally related to the liver and the pancreas. It's about 1/10 of the small bowel's total. The next 4/10 is the jejunum. The final segment is the ileum, which is hooked into the large intestine near the appendix on the right side and empties into the large intestine.
"The job of the small intestine is to basically provide a place where complex nutrients — foods — can be broken into small molecules we can absorb," Jackson said. "It does it sequentially as things go down into the intestine. There are lots of enzymes, chemical reactions and it also has to absorb water."
There, food breaks down and some of the water is absorbed, as well as the "good stuff," the nutrients. The large intestine salvages what's left. If it isn't absorbed, normal stool doesn't form, causing diarrhea. The small intestine is more crucial. If part of it is lost to disease or obstruction, it will still digest food, but there's a limit to that. If a significant portion of the small intestine doesn't work or is missing, an individual can't absorb enough food and water and has to rely on the support of intravenous nutrition, delivered through a central line close to the heart.
How much small bowel you have is no more important than what part of it you have. The duodenum must be there, because that's where digestion starts. People who don't have a good portion of their ileum miss special functions. It's does most of the absorbing.
And that's Jacob's problem. He has a third of his small bowel left, none of it the ileum. His large intestine is intact and helps salvage nutrition, but it's not enough.
Small bowel syndrome has many causes. It's not uncommon in newborns and premature infants for the small bowel to twist around itself and kill off the blood supply. Jacob's small bowel narrowed, most likely from a blood vessel problem, a twist, when he was developing. Cystic fibrosis can lead to short bowel syndrome, as can inflammation. Newborns and premies sometimes get infections that kill off the small bowel, but physicians haven't been able to find the germ that causes it.
The IV line poses a risk of serious infections, and Jacob has had more than his share. And replacing the central line, even periodically, can damage veins. "You can run out of veins," Jackson said. "It gets harder and harder."
Intravenous nutrition is never good for the liver, which "likes to receive its nutrition from the intestine," Jackson said. "It gets blood from there and likes first crack at the nutrition from there." If the liver can't be fed effectively, it is damaged. And after receiving nutrition through the central line, the liver always shows some signs of injury.
To counteract that, Alisha Roddy feeds her son normally, as well. But it's not normal because he can only tolerate tiny amounts of food, maybe a teaspoon full an hour. He has diarrhea all the time. Still, his liver is doing "fairly well," Jackson said.
That adds urgency to the race. The toddler needs a new small bowel soon to avoid needing a liver transplant as well.
"Almost all liver transplant places say you should protect your liver. If you can transplant the intestine before the liver's bad, that's a good thing," said Jackson. "You should do whatever you can to keep your own organs and make them work and adapt."
There are techniques to help some people cope with short bowel syndrome, including a special surgery that lengthens the intestine by splitting it. Doctors try to prevent obstruction and infection and feed someone normally as much as possible. The odds improve for people who can keep their own organs.
But there are people, like Jacob, whose bodies don't seem to adapt to the syndrome. That means a transplant, and there are never enough to meet need. Of 20,000 transplants in the United States last year, about 70 were small bowel.
Few medical centers will perform small bowel transplants because they're extremely complicated. Jacob must go to Pittsburgh, Miami or Nebraska. Sometimes doctors do a bone marrow transplant along with the small bowel to transplant the immune system, as well.
The waiting list for a small bowel transplant is as much as a year long, and many patients die waiting, Jackson said.
Older children and adults also develop the syndrome, usually as a result of the small intestine twisting on itself. Other causes include injury, surgery, vascular damage, inflammatory bowel disease like Crohn disease, and malabsorption disease.