Table of Contents
see also: gastroenterology
Newsbreak - new vaccine starting trials 2009 for Rx of coeliac - see here
- now known as gluten enteropathy
- results from an abnormal immune response to gliadin, a component of dietary gluten, found in wheat, barley, rye and possibly oats.
- this causes villous atrophy of the small bowel mucosa, which in turn leads to malabsorption and a predisposition to gastrointestinal malignancy, particularly carcinoma of the oropharynx and oesophagus, and small bowel lymphoma.
- the disease may present in either children or adults, but it is uncommon in adolescence and its manifestations may disappear at this age.
- largely a disorder of Caucasians - in Australia it affects approximately 1 in 100 to 1 in 2000 people depending upon accuracy of diagnosis.
- subclinical, or `silent', celiac disease, detected by antibody screening, may be up to ten times more frequent.
- Patients with coeliac disease typically have the HLA-B8, DR3, DQ2 or DQ8 haplotype
- thus coeliac disease occurs in 10% of first-degree relatives, 30% of HLA-identical siblings and 70% of monozygotic twins.
- however, approximately 20% of the general population have the same HLA alleles but do not develop coeliac disease.
- When gliadin enters the small bowel mucosa, it undergoes enzymatic deamidation by tissue transglutaminase (tTG), an extracellular enzyme found in the connective tissue of the small bowel.
- In susceptible people, the gliadin-tTG complex becomes antigenic, producing a local immune response. This leads to the characteristic villous atrophy of coeliac disease. As part of this immune reaction antibodies to tTG are produced and are recognised as endomysial antibodies.
- The classic presentation of a patient with abdominal distension, steatorrhoea, weight loss, bruising and other obvious features of malabsorption is now uncommon.
- adults tend to present with milder symptoms such as:
- diarrhoea, flatulence and bloating, or fatigue.
- isolated iron and/or folate deficiency anaemia
- the clinical features have also changed in children who now may present with:
- growth or pubertal failure, recurrent abdominal pain, iron and/or folate deficiency or malaise.
- irritability and poor school performance.
- non-GIT presentations:
- recurrent mouth ulcers
- delayed menarche, infertility or repeated miscarriage
- untreated coeliac disease is reported to have a 8-9x risk of recurrent miscarriages compared with treated patients but requires further study1)
- most adults will have significant osteopenia at presentation.
- 5% of adults diagnosed with osteoporosis will be found to have underlying coeliac disease as the cause
- at least 75% of patients with dermatitis herpetiformis will be found to have typical villous atrophy on small bowel biopsy whilst most of the others will have more subtle changes.
- other associations:
- type 1 diabetes
- autoimmune thyroid disease
- IgA deficiency
- atrophic gastritis
- peripheral neuropathy
- primary biliary cirrhosis
- alopecia areata
- Down's syndrome
- muscle weakness due to hypokalaemia
- cryptogenic neurological illness, in particular epilepsy and ataxia (leading to the term `gluten ataxia')
- non-Hodgkin's lymphoma in < 1% patients
- NB. arthritis is a rare association although rheumatoid arthritis has increased prevalence
- requires a high index of suspicion
- NB. trial of gluten-free diet has NO place in diagnosis or Rx - gluten-free diet must be lifelong
- if low index of suspicion but alone, these are not diagnostic
- “coeliac disease serology”
- deamidated gliadin IgG
- now used instead of endomysial (EMA) antibodies
- h-Transglutaminase (h-TTG) IgA recomb Ab
- now used instead of IgA-TTG
- false negatives may occur if:
- patient on a gluten-free diet
- patient has IgA deficiency - 3-5% of patients with coeliac disease
- the total serum IgA concentration should therefore also be measured at the same time as antibody tests if this is suspected
- useful in checking dietary compliance
small bowel biopsy
- now taken from distal duodenum rather than jejunum
- essential in all patients
- repeat after 6 months on gluten free diet
- if coeliac disease is a possibility, duodenal biopsies should be taken in patients undergoing endoscopy for unexplained iron deficiency anaemia.
- lifelong gluten-free diet
- gluten refers to two families of proteins (glutenens and gliadins) found in mature grains such as wheat, barley and rye, and thus in foods such as bread, cakes and pasta
- gluten is sticky, stretchable, elastic, and can act as a thickening agent
- gluten-free diets can cause deficiency in iron, folate, thiamine, calcium, vitamin B12, and zinc
NEJM 2011 364:8 p783-4
coeliac.txt · Last modified: 2014/09/09 13:02 by 127.0.0.1