Antibody tests boost celiac disease diagnoses

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Antibody tests boost celiac disease diagnoses

http://www.reuters.com/article/idUSTRE5BE32N20091215?feedType=nl & feedName=usheal\

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NEW YORK (Reuters Health) - The advent of antibody testing to diagnose celiac

disease has led to a substantial increase in the number of cases detected among

children, a new study suggests.

Celiac disease is a digestive disorder caused by an abnormal immune response to

gluten, a protein found in wheat, rye and barley -- as well as in many everyday

items like medicines and vitamins. The disease damages structures in the lining

of the small intestine called villi, which then impairs the body's absorption of

nutrients.

Traditionally, " classic " celiac disease was diagnosed when babies and young

children developed symptoms like chronic diarrhea and significant weight loss.

But in more recent years, experts have found that celiac disease has a wider

variety of symptoms -- including chronic abdominal pain, acid reflux, vomiting

and constipation -- particularly in older children.

This greater understanding of celiac symptoms has in large part been credited to

blood tests that detect certain antibodies produced in people with the disorder.

These tests have allowed more and more people who have " atypical " celiac

symptoms to be referred for definitive testing with an intestinal biopsy --

where a small piece of tissue is removed from the small intestine to check for

damage to the villi.

In the new study, published in the journal Pediatrics, researchers found that

the rate of celiac disease diagnoses at their children's hospital tripled after

the introduction, in 1997, of antibody testing.

And most of those children, the study found, did not have classic celiac

symptoms.

Although the study covered only a single center, the increase in celiac

diagnoses is not an isolated situation, according to senior author Dr. J. Decker

Butzner, of the University of Calgary and Alberta Children's Hospital in Canada.

Other research has similarly found increases in celiac diagnoses after the

introduction of antibody testing.

The current findings are based on 266 children who were referred to Alberta

Children's Hospital between 1990 and 2006 for an intestinal biopsy and

ultimately diagnosed with celiac disease.

Between 1990 and 1996 -- before antibody tests were available -- 36 children

were diagnosed with celiac, 67 percent of whom had been referred for testing

because of " classic " symptoms. The children were typically about 2 years old

when diagnosed.

In contrast, between 2000 and 2006, 199 children were diagnosed with celiac,

with the typical age at diagnosis increasing to age 9. Only 19 percent of these

children had classic celiac symptoms.

Instead, 38 percent had atypical digestive symptoms, like chronic abdominal

pain, while 15 percent had non-digestive symptoms, such as iron deficiency and

poor growth.

The rest of the children -- 28 percent -- had shown no clear symptoms, but were

referred for testing because they had a family history of celiac disease or had

medical conditions associated with a higher risk of the disorder, including type

1 diabetes and Down syndrome.

In an interview, Butzner said that blood testing for celiac disease should be

performed when a child has chronic gastrointestinal symptoms of any kind that do

not improve on their own or respond to treatment.

Testing might also be appropriate for children with a family history or

celiac-associated medical conditions -- though, Butzner said, it is

controversial whether this should be done in the absence of celiac symptoms.

He also stressed that the antibody blood tests are only a screening procedure

and do not provide a definitive diagnosis. A positive test result, Butzner said,

needs to be followed up by an intestinal biopsy.

This is important, Butzner explained, because the treatment for celiac disease

is to go on a lifelong gluten-free diet. While effective at easing symptoms and

healing and preventing intestinal damage, the diet can also be expensive and

challenging to follow.

SOURCE: Pediatrics, December 2009.