A classical set of coeliac disease symptoms no longer reflects the profile of most newly-diagnosed patients, according to a new study from Italy.
Instead, doctors need to take other symptoms into account and consider the possibility of coeliac disease, even when patients don't fit the old image of the condition, researchers say.
"It's been a gradual phenomenon since the 1970s that fewer people are presenting with the classical diarrhoea and more with non-classical or silent presentation, both in adults and children," said Dr. Peter Green, who wasn't involved in the study.
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"We don't actually know why one person has diarrhoea and another presents with abdominal pain or osteoporosis," said Green, director of the Coeliac Disease Centre at Columbia University in New York.
Dr. Umberto Volta and his co-authors write in the journal BMC Gastroenterology that just 15 years ago, coeliac disease was still thought of mainly as a rare paediatric food intolerance, whose most common signs were diarrhoea and intestinal damage that was diagnosed through a biopsy.
The disease is now known to be an autoimmune disorder, caused by an inability to tolerate the gluten protein in wheat, barley and rye.
Inflammation of intestinal lining
Eating gluten typically causes inflammation of the intestinal lining in people with coeliac disease and makes it hard to absorb nutrients.
Research shows that more than 1 percent of people worldwide have the disease, but most may not know it, the authors of the study note. The diagnosis is based on a blood test for signs of the abnormal immune response, such as antibodies, as well as biopsy in some cases.
With his colleagues, Volta, a professor of medicine at the University of Bologna in Italy and vice president of the Ethical Committee at St. Orsola-Malpighi University Hospital, looked at the coeliac patients diagnosed over the course of 15 years at that hospital.
The study involved 770 patients, 599 of them female, diagnosed between 1998 and 2007. Nearly half were diagnosed during the first 10 years of the study period and the rest in the last five years, indicating a steep rise in rates of diagnosis.
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Among all the patients, 610 people, or 79 percent, had symptoms when they were diagnosed. But most of their problems were not the typical diarrhoea and weight loss, but rather "non-classical" issues like bloating, osteoporosis and anaemia. Diarrhoea was a symptom in just 27 percent of patients.
Indeed, classical symptoms became less common over the years, decreasing from 47 percent of patients during the first 10 years to 13 percent in the last five. Meanwhile, other problems, as well as a lack of any significant related illness, increased by more than 86 percent.
Other non-classical symptoms
"The most striking change in clinical presentation of coeliac disease over time has been the decrease of diarrhoea as the leading symptom and the progressive increase of other non-classical gastrointestinal symptoms (such as constipation, bloating and alternate bowel habits as well as gastro-oesophageal reflux, nausea, vomiting and dyspepsia)," Volta said in an e-mail to Reuters Health.
"A high proportion of coeliac disease patients did not show any gastrointestinal symptom, but they displayed extra-intestinal manifestations such as iron-deficiency anaemia, unexplained osteoporosis, abnormalities of liver-function tests and recurrent miscarriages," he said.
The most common illness associated with coeliac was thyroid disease. Only half the patients had severe intestinal damage, and 25 percent had partial damage.
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In later years, more patients were diagnosed through blood tests. That may be one factor accounting for the changing pattern of typical symptoms, Volta said, because the patients were diagnosed earlier, before gluten had done its damage.
"The effects of gluten weren't as severe yet," Volta said. "The story of coeliac disease has been radically changed by the discovery coeliac disease-related antibodies, which identify plenty of unsuspected cases."
Green agreed that testing has vastly improved diagnosis of the disease. He said that in the United Kingdom, anyone with iron deficiency or migraine is tested for coeliac disease.
Common and underdiagnosed
While most coeliac specialists understand the varied symptoms, other physicians might not, he said. Green pointed out that in the United States, only 17 percent of people with the disease are actually diagnosed.
"Anyone can have coeliac disease, it's common and underdiagnosed," said Green. "The message we want to get out is if you think you've got coeliac disease, don't just go on a gluten-free diet, test for it."
Volta said he hoped the study reminded doctors about the many problems that can signal coeliac disease.
"I hope doctors keep in mind that coeliac disease is a very frequent food intolerance, which should be investigated not only in patients with diarrhoea and overt malabsorption, but also in people (with other symptoms)," Volta said.
"The treatment by gluten-free diet improves the quality of life in symptomatic patients and prevents complications in all coeliac disease patients including those without symptoms," he said.
SOURCE: http://bit.ly/1ATNpT3 BMC Gastroenterology, Nov. 18, 2014.
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