{"id":2076,"date":"2018-02-20T16:12:29","date_gmt":"2018-02-21T00:12:29","guid":{"rendered":"https:\/\/phcprimarycare.org\/?p=2076"},"modified":"2018-03-08T16:01:32","modified_gmt":"2018-03-09T00:01:32","slug":"diagnosis-of-celiac-disease","status":"publish","type":"post","link":"https:\/\/phcprimarycare.org\/?p=2076","title":{"rendered":"Diagnosis of Celiac Disease"},"content":{"rendered":"

By Robert Moore, MD, MPH, MBA, Chief Medical Officer
\n<\/a><\/strong><\/p>\n

Clinical Case:\u00a0 A 23 year old woman with a several year history of gastritis (with prior treatment for H. pylori), migraine headaches, geographic tongue and anemia has a complete blood count ordered by her primary care physician, finding a hemoglobin of 9.7 with microcytic indices.\u00a0 She has an uncle with gluten intolerance, first developing these symptoms after being treated successfully for H. pylori-associated duodenal ulcer disease.<\/p>\n

What is the probability that this woman has Celiac disease?\u00a0 What does Helicobacter pylori infection have to do with Celiac Disease?\u00a0 What is the best first test to perform?<\/p>\n

 <\/p>\n

Celiac Disease is an autoimmune disease affecting about 1% of the U.S. population, but 83% of these individuals are either undiagnosed or diagnosed with other conditions without making the link to the underlying Celiac Disease.\u00a0 Of those 17% who are diagnosed, the mean time between onset of symptoms and diagnosis is between 8 and 11 years.\u00a0 It is arguably the most underdiagnosed and misdiagnosed condition in the United States, although this is beginning to change, thanks to new genetic and antibody tests that help point to the right diagnosis before doing a confirmatory duodenal biopsy.\u00a0 Primary care providers need to know what signs, symptoms and blood tests should prompt further workup, and how to do the initial, low-invasive testing.<\/p>\n

On the flip side, there are a growing number of people who have (or believe they have) gluten intolerance, who do not have Celiac disease.<\/p>\n

The history of the discovery of Celiac Disease<\/a> is a case of an astute clinician making an observation under conditions of a natural experiment.<\/p>\n

In the 1930s, Dutch pediatrician Willem Dicke was studying a mysterious, often fatal disease among children, where they were losing weight and malnourished in spite of plenty of vitamin-rich caloric intake.\u00a0 While he suspected this malabsorption syndrome was related to diet, he was not able to pinpoint the culprit until the winter of 1944, during World War II.\u00a0 Dutch railway workers held a strike in support of the Allies, prompting the Nazis to cut off food shipments to Dutch civilians, which led to mass starvation, except for Dr. Dicke\u2019s pediatric patients, who actually got better.<\/p>\n

During 1945, the allies parachuted bread to Holland, ending the Hunger Winter, ending the starvation, but Dr. Dicke\u2019s patients immediately relapsed.\u00a0 He hypothesized that grains were the cause of the malabsorption syndrome.\u00a0 He performed an experiment on the children, putting them on a gluten free diet, showing that the symptoms were completely gone, then put them back on a regular diet, showing that the symptoms came back.<\/p>\n

 <\/p>\n

Causes of Celiac Disease<\/u>: \u00a0As an autoimmune disease, there is a combination of a genetic predisposition and environmental factors.<\/p>\n

    \n
  1. Genetic: <\/a>\u00a0In terms of genetic predisposition:\u00a0 95% of those with Celiac Disease have a gene called HLA DQ2, and most of the remainder have HLA DQ8.\u00a0 However, of those individuals with either the HLA DQ2 or HLA DQ8 genes, only 3% have Celiac Disease.<\/li>\n<\/ol>\n

    In summary, although negative genetic testing can rule out celiac disease, a positive test cannot confirm the diagnosis.<\/p>\n

    Thirteen additional genes are associated with an increased risk that those with DQ2 or DQ8 will develop Celiac Disease.<\/p>\n

    Among first degree relatives carrying the DQ2 or DQ8 gene, 30% of symptomatic first degree relatives have Celiac Disease, and 10% of asymptomatic first degree relatives also have the disease found on intestinal biopsy.\u00a0 Overall, between 5 and 22% of individuals with Celiac Disease have a first degree relative who also has Celiac Disease.<\/p>\n

      \n
    1. Exposure to Gluten: <\/a>The incidence of Celiac Disease is higher in populations with larger consumption of wheat.\u00a0 Thirty years ago there was literally an epidemic of Celiac Disease in Swedish infants, when low rates of breastfeeding combined with standard use of wheat in infant formula, which led to diarrhea and failure to gain weight.\u00a0 In the 1980s, Celiac Disease was widely recognized and diagnosed in Italy, a country with a culinary culture of pasta, bread and pizza dough, all rich in gluten.\u00a0 Northern India (which consumes more bread) has a higher rate of Celiac Disease than southern India, where rice is the staple.<\/li>\n<\/ol>\n
        \n
      1. Protective Factors<\/u>: When genetic factors and diet are the same, the incidence of Celiac Disease is lower in lower income populations compared to higher income populations, as found in epidemiological studies.\u00a0 Using stored serum samples, researchers have found a four-fold increase in incidence of Celiac Disease over the past 50 years.\u00a0 While overall income has increased in that period, what is the underlying cause for this association?<\/li>\n<\/ol>\n

        An epidemiological study published in 2013<\/a> suggests one potential mechanism for this finding:\u00a0\u00a0 Helicobacter pylori infection, whose incidence is higher in low income populations, is associated with half the rate of Celiac Disease.\u00a0 Increased recognition of H. pylori infection as a cause of gastritis and peptic ulcers has led to widespread treatment, solving one problem but potentially increasing the risk of another.\u00a0\u00a0 There may be other protective factors related to other bacterial flora which we do not yet understand.<\/p>\n

         <\/p>\n

        Clinical Diagnosis:<\/u><\/p>\n

        Many common conditions of the intestinal tract and elsewhere in the body may be associated with Celiac Disease, either directly by the autoimmune process, mediated through the resulting malabsorption\/malnutrition\/vitamin deficiency or associated with the psychological stress of the other symptoms.\u00a0 These include:<\/p>\n