The stomach ache people look with some envy at the headache people.

“for some reason people respect headaches,” said Carlo Di Lorenzo, a leading pediatric gastroenterologist and a professor of clinical pediatrics at Ohio State. “I’ve never seen a parent or a pediatrician tell a child complaining of a headache,’ ‘you don’t have a headache — it’s not real.’ Bellyache is just as real as headache.”

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Indeed it is, and recurrent abdominal pain in children is common, frustrating and often hard to explain.

Consider a girl who came to the clinic for her 10-year physical exam. she gets bellyaches and had a bad one that week, but her stomach wasn’t hurting right at the moment.

She had been treated for constipation, tested for celiac disease and other problems and every blood and stool test over the two years since the pain began was completely normal. one night she went to the emergency room because the bellyache was so bad — and her abdominal X-rays were normal as well.

The diagnostic term for this common and perplexing condition is “functional abdominal pain”: recurrent stomachaches, as the American Academy of Pediatrics put it in 2005, with no “anatomic, metabolic, infectious, inflammatory or neoplastic disorder” to explain them.

When I was a resident, we often smirked when we spoke of functional abdominal pain, treating it as a code for a troublesome patient, dubious symptoms or an anxious family. However, recent research suggests we were too biomedically narrow in our thinking.

Scientists are coming to understand that abdominal pain is transmitted by a specialized nervous system that may be hypersensitive or hyperactive in some children. Studies in which researchers inflated balloons in children’s intestines suggested that those with functional abdominal pain might be unusually sensitive to any distension on the inside.

“We think in terms of a biological-psychological-social model” for pain, said Joel R. Rosh, a pediatric gastroenterologist at Goryeb Children’s Hospital in Morristown, N.J., and an associate professor of pediatrics at new Jersey Medical School. “when a child says, ‘My belly hurts,’ what drives me crazy is people say, ’no it, doesn’t.’

”why would people say that? You’re feeling something! How much is biological, how much is psychological, how much is social?“

The improved understanding of how such pain develops — and can be treated — has changed the ways that pediatricians look at the problem, but it hasn’t necessarily made it easier to take proper care of these children, to worry over them enough but not too much and, above all, to make them feel better.

The problem may start with some initial insult, an infection or inflammation that may affect pain pathways in the child — and may also set up psychological patterns and anxieties in the child and response patterns and anxieties in the parent.

Then the child continues to be extremely aware of sensations coming from the gastrointestinal tract, even when the initial illness is over. the challenge to the parents — passed on to the pediatrician — is how diligently these pains should be investigated, how many tests a child should be subjected to, how much money should be spent.

“one thing fairly well established is that as soon as you make a referral to a subspecialist, cost increases by fivefold,” Dr. Di Lorenzo said. “We’re going to tend to do a lot more tests.” the more anxious the parent, he said, the more tests may be done for reassurance.

With the 10-year-old girl, I was trying hard not to refer her to a subspecialist. she was growing well and had none of the red flags that signal a need for a medical work-up.

We suggested that she learn techniques to cope with her abdominal pain and maybe see a counsellor to talk about anxiety. Her mother thought we meant the pain was imaginary.

“the vast majority of data suggest that what helps the children is working with the brain more than working with the gut,” Dr. Di Lorenzo said. “Hypnosis is clearly more effective than medication.”

And the medications that do work are often those that work on the enteric nervous system (which uses serotonin as a neurotransmitter), so low doses of antidepressants are sometimes helpful with functional abdominal pain.

Miranda A.L. van Tilburg, a psychologist who is an assistant professor of medicine at the University of North Carolina, was the lead author of a study published a year ago in Pediatrics which showed good effects from a treatment called guided imagery.

“We would give them therapeutic suggestions,” van Tilburg said, “like imagining something in your hand that melts in your hand like butter and then you put it in your tummy and it makes it stronger, or imagine drinking your favourite drink and again the inside of your tummy is coated with this special layer.” the children were sent home with CDs and instructions to practise the imagery regularly as a prevention strategy.

Our patient said she didn’t want to see any more doctors. she didn’t want any more blood tests, and she didn’t want tests she had heard about that involved tubes. Her mother didn’t really want those tests either, since as she said, they never seemed to find anything wrong. Neither was enthusiastic about seeing a counsellor, but they finally agreed.

It’s an appropriate strategy. “It’s very disempowering to have this alien living in your belly,” Dr. Rosh said. “How about if I learn that my belly doesn’t have to run my life?”

And how do you help doctors, parents and children get past the idea that functional abdominal pain is not “real,” that a child doubled up with pain is faking it, that it’s all in his head?

“if it was all in his head, he’d have a headache,” Dr. Rosh said. “Clearly there’s something happening in his belly.”

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