NEW YORK — Celiac disease doesn't look like it used to, and consequently the diagnosis is frequently missed by physicians who think of it as a disease of wasting, reported experts at an international symposium on celiac disease.
Traditionally, textbook pictures of celiac patients have shown the wasted limbs and swollen abdomens characteristic of malnutrition—but today, up to 40% of patients are overweight and 13% are obese at presentation, according to Dr. William Dickey of Altnagelvin Hospital, Londonderry, Northern Ireland.
Dr. Dickey's study of body mass index at presentation in 371 celiac patients over a 10-year period found that only 5% were underweight, and few presented with the classic symptoms of diarrhea and anemia (Am. J. Gastroenterol. 2006;101:2356–9). The well-documented problem of missed or delayed diagnosis of celiac disease may be partially explained by failure to recognize its modern presentation, he suggested.
In response to “significant lack of awareness and very substantial underdiagnosis of patients,” the National Institutes of Health has embarked on an awareness campaign aimed at primary care providers, said Dr. Stephen James, director of the digestive diseases and nutrition division of the NIH, who also spoke at the meeting.
“Physicians do not perceive the underdiagnosis of celiac to be problematic,” he said, citing findings from the recent NIH Consensus Development Conference on Celiac Disease (www.consensus.nih.gov/2004/2004CeliacDisease118html.htm
Recent evidence suggests that the prevalence of celiac disease—about 1%–-is the same in both Europe and North America (Arch. Intern. Med. 2003;163:286–92). Higher prevalence rates are seen in first-degree relatives (5%–15%), monozygotic twins (70%–75%), and patients with other autoimmune disorders.
The prevalence of celiac disease is slightly higher than that of either type 1 diabetes or Crohn's disease, but many physicians still have the misperception that celiac disease is a rare disorder, Dr. James said. Although many primary care physicians surveyed said they had never seen a case of celiac disease, they probably had several undiagnosed patients in their practice, he said.
Extragastrointestinal signs and symptoms of celiac disease—such as dermatitis herpetiformis, neurologic disorders, more than one miscarriage, osteoporosis, and dental and oral problems—often go unrecognized, he noted.
The ambiguity of diagnostic tests contributes to the elusiveness of celiac disease, once called a “clinical chameleon” by Dr. Alessio Fasano, a leading expert from the University of Maryland Medical Center, Baltimore. In addition to the nonspecific spectrum of clinical symptoms, diagnostic criteria have hinged on positive serum antibodies and small bowel biopsies, but equivocal serologic and histologic results are frequently found, experts agreed.
The combination of positive serology followed by a positive bowel biopsy and response to a gluten-free diet confirms the disease with roughly 95% accuracy, said Dr. Edward J. Hoffenberg, of the University of Colorado Health Sciences Center in Denver. But his work, and that of others, has shown that an individual's degree of immune response can fluctuate, especially if they are not ingesting gluten at the time of testing, and the characteristic villous atrophy seen on bowel biopsies is not always present.
A diagnosis of celiac disease within a family should alert physicians to the increased risk for other family members, said Dr. Chris Mulder of Vrije Universiteit Medical Center, Amsterdam. Genetic testing can rule out celiac for such risk groups, because 99% of celiac patients express the DQ2 or DQ8 haplotype.
However, 30% of those with genetic susceptibility may not develop celiac, he said. Genetic testing is part of the celiac work-up in the Netherlands, but it is less available in North America, making family history a more realistic genetic marker.