Cœliac disease is believed to affect 0.3-1% of the population in almost all countries and ethnic groups where it has been investigated. Previously regarded largely as a childhood problem it is now recognised to affect mostly adults, with about 25% of diagnoses being made in people over 60 years of age. Typically the presenting features of malabsorption (diarrhoea and weight loss) are suggestive of cœliac disease, but case presentations in the BMJ indicate that often few or no gastrointestinal symptoms are present, and some people with the condition can even be obese. The condition may also present insidiously, for example, with iron deficiency anaemia, osteoporosis or neurological symptoms

Historically diagnosis is based on atrophy of the lining of the small intestine, which recovers on a gluten-free diet. An endoscopic examination is needed to see this. Since antibody testing has become available, anti-endomysial and anti-transglutaminase antibodies are often used as a preliminary and less invasive method of screening.

Where both intestinal atrophy and blood antibodies are found the diagnosis of cœliac disease is straightforward. Difficulties arise when one or other of these is not found, and the diagnosis is particularly difficult when both are negative. The objective of orthodox medical diagnosis of cœliac disease is to determine treatment, i.e. a gluten-free diet. Some individuals with cœliac disease have no symptoms and find a gluten-free diet very limiting. When the diagnosis is in doubt and individuals have few or no classical symptoms of cœliac disease, treatment approach is more problematic.

Intestinal biopsy needs expertise: the disease may be patchy, so biopsies from several sites in the upper intestine should be carried out, and although cœliac disease is regarded as an upper small intestinal disorder, it is possible for atrophy to be present at the far end of the small intestine. If endoscopy is carried out following a positive antibody test, the individual may have already started a gluten-free diet, and the results of endoscopy can then be negative.

The results of antibody testing in any area depend on the population used to standardise the test, the particular test used, and the laboratory expertise. A combination of anti-endomysial and anti-transglutaminase antibodies is often used, and can be highly predictive of the condition. Antibody negative cases of cœliac disease do occur, a possible reason for this is IgA deficiency. This is more common in cœliac disease and since anti-endomysial and anti-transglutaminase antibodies are normally measured as immunoglobulin A antibodies they will be absent in individuals with IgA deficiency. Therefore in patients with IgA deficiency, IgG anti-endomysial and anti-transglutaminase antibodies need to be checked.

There is a strong association between being an ABH non-secretor and having overt cœliac disease. Non secretors being about 200% more likely to be cœliacs than secretors. Non-secretors also have lower levels of IgA than secretors. One study reported that up to 48% of patients with cœliac disease were reported to be ABH non-secretors. This appears to be especially true for the Lewis negative (a-b-) phenotype. Evidence suggests an increased prevalence of complications and cœliac-associated abnormalities is also found in non-secreting and Lewis negative individuals with cœliac disease.

This may go some way to explaining the 'atypical' cases of cœliac disease reported in the BMJ. Gluten-free diets are usually heavily reliant on corn/maize-based substitutes. Using corn as a staple is likely to increase weight due to the inhibiting effect it has on insulin production, which may cause weight gain, particularly in non-secretors, who are more prone to syndrome X.

The possibility of cœliac disease should be borne in mind even with 'atypical' presentations and negative diagnostic results. It would appear that eating according to reccomendations of blood group and secretor status would still be of benefit when diagnosed as cœliac or not, although with a positive diagnosis of cœliac disease gluten should also be avoided.

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References

Saunders DS, Hurlstone DP, McAlindon ME, Hadjivassiliou M, Cross SS, Wild G, et al.

Antibody negative coeliac disease presenting with coeliac crisis in the elderly people—an easily missed diagnosis.

BMJ 2005;330: 775-6.

PMID 15802721



Furse RM, Mee AS.

Atypical presentation of coeliac disease.

BMJ 2005;330: 773-4.

PMID 15802720

Pathbase 3.0 - Celiac disease