- Prevalence is about 1 in 100. However it is thought that only ½ of cases are actually diagnosed
- Most common incidence is in children, and in those over 60, although it can occur at any age
- Slightly more common in women over 60 than in men over 60
- 30% risk for sibling, and 10% risk for first degree relatives, indicating an element of genetic susceptibility
- It is a T-cell mediated auto-immune disease. The body has an adverse reaction to breakdown products of gluten (gliadins). This results in the production of two antibodies – anti-gliadin, and anti-endomysial. Anti endomysial antibody is the auto-immune. This attacks TGG (tissue transglutaminase) which is the enzyme responsible for gluten breakdown.
- There is hypertrophy of crypts, and atrophy of the villi thus the overall wall thickness remains stable, but the surface area for absorption becomes greatly reduced
- The proximal small intestine is most affected – due to the higher concentration of gluten products in this area (they get more broken down the further along the intestine they travel)
- General malaise / tiredness – often as a result of iron deficiency anaemia due to malabsorption
- Diarrhoea – due to malabsorption
- Nausea / vomiting
- Angular stomatitis – anaemia
- Weight loss
- Oral ulceration
- Blood Test for anti-endomyisal antibody and/or anti tTg (anti tissue transglutaminase). Anti tTG is a newer and more sensitive specific test and should be used in preference if available.
- Endoscopy to take a duodenal biopsy for histological examination. 50% of those with positive antibody test may not have histological changes. These people are ‘latent Coeliacs’ and are highly likely to develop true Coeliac disease in the future.
Histological findings typically involve: hypertrophy of the crypts, and atrophy of the villi, giving the mucosa a flattened appearance. the overall thickness of the mucosa is not changed. There must also be an increase in the number of inflammatory cells in the lamina propria for a diagnosis to be made.
There are no set criteria for diagnosis, but typically you will need:
- Evidence of malabsorption (steatorrhoea, vitamin / nutritient deficiency)
- Villous atrophy on duodenal biopsy
- Weight loss
- Features resolve upon adoption of gluten free diet
- Osteopaenia – reduction in bone density – due to lack of calcium absorption
- Osteoporosis – due to prolonged lack of calcium absorption
- Osteomalacia– due to vitamin D / calcium malabsorption
- Cerebellar disorders – due to problems with calcium metabolism
- Neurological disorders – e.g. parasthesia and muscle weakness
- Increased incidence of other auto-immune conditions
- Increased risk of malignancy – GI lymphoma (rare) or can be oesophageal, gastric, brain or breast (these are even rarer)
- Prevalence is about 1 in 250. In the past, estimates for the prevalence were far lower, as mild cases were missed and the disease couldn’t be tested for serologically.
- It is common in Northern Europeans, particularly in Irish populations.
- 50% of patients are asymptomatic – thus the true presenting incidence is 1 in about 500. The 1 in 250 figure includes people who have ‘silent’ disease, as well as genetically susceptible people who if left in treated are likely to develop the disease in the future.
- It is rare in black Africans.
- There is also a genetic component although the exact mode of inheritance is not known. 10-20% of first degree relatives will have the condition, although it is often asymptomatic. There is a 30% risk for siblings.
- It can occur at any age, although peaks are in infancy, and between ages 50-60. At the later age of presentation, females are slightly more likely to be affected than males.
T-cell mediated autoimmune disease
Initially there is an immune reaction to gluten – this is why the proximal gut is more affected – because this is where there is the highest concentration of gluten. However, this reaction against gluten eventually becomes an auto-immune reaction against the small intestinal mucosa.
- Anti-endomysial – these can be used to test for the presence of the disease. The test is 95% specific. The endomyisal anti-body mainly attacks TGG – Tissue transglutaminase. These are the enzymes that break down the gluten peptides, and thus allow them to be presented to T-cells in genetically susceptible individuals.
- The mucosa of the proximal small bowel is the most readily affected. As you move towards the ileum, the affect decreases, due to the fact the ‘toxic’ peptides are broken down into smaller fragments.
- There is an absence of villi, and thus the mucosal surface becomes flat.
- Increase in the number of inflammatory cells in the lamina propria
- There is hypertrophy of the crypts, and atrophy of the villi, and thus the overall mucosal thickness remains the same. There are chronic inflammatory cells in the lamina propria.
- Children - The disease will typically present with weaning onto cereals. Symptoms will include diarrhoea (steatorrhea), malabsorption and failure to thrive.
- Adults - In older children and adults it may present with more non-specific symptoms, such as failure to grow properly, or more vague symptoms, such as fatigue, abdominal pain, abdominal distension, iron-deficiency anaemia, (angular stomatitis), weight loss, and oral ulceration.
- Often the only sign is iron-deficiency anaemia.
- 1/3 of patients are asymptomatic.
- Skin rash - There is a very specific skin rash linked to coeliac disease. About 1/5 patients will develop the rash. The rash tends to be very itchy and it found mainly on the trunk. They are more like little red spots than a rash. It is called Dermatitis herpetiformis.
- Test for anti-endomysial antibody and also for transglutaminases. These tests are highly sensitive and specific. If these are positive, then you should do an endoscopy, and take histological samples via duodenal biopsy (>4 samples should be taken). A certain number of patients may not have histological abnormalities and these people are called ‘latent coeliacs’ – and these patients are likely to develop coeliacs in the future, but do not actually have the disease yet. The changes to the mucosa tend to be subtle and can be missed if the histological test is not good enough.
- Histological abnormalities- these include, cuboidal surface cells, and an increase in inflammatory cells. also the receptors on T cells are different. Normally , they are of the γ \ δ type, but in coealic’s they become α \ β. This is specific to coeliacs, and is irreversible. In Latent coelicas, the only noticeable change is the higher number of inflammatory cells present.
- The changes seen in coeliacs are measured in the Marsh scale. This has 4 levels (I-IV, IV being the most severe), with most coeliacs patients being level III. Marsh type IV is associated with a non-response to a gluten-free diet, and thus has a much greater risk of complications.
- People who are diagnosed with coeliacs tend to always be screened for osteopenia – DEXA scan. It can be surprising – some young 20 somethings often have osteopenia.(Osteopenia is a reduction in bone density –basically a pre-osteoporosis state.)
- Cerebellar disorders – due to calcification of the cerebellum.
- Neurological disorders – such as parasthesia and muscle weakness
- Increased incidence of atopy and auto-immune disease – particularly thyroid disease, type-1 diabetes etc.
- Increased risk of malignancy – this can be gastric, oesophageal, brain and breast. Also increased risk of T-cell lymphoma and MALT, although this is still rare.
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