Medical terms
A brief glossary of medical terms related to coeliac disease.
| Abdomen | Often called the belly; the section of the body between the chest (thorax) and pelvis. Contains many parts of the digestive tract (e.g. stomach, small intestine, and large bowel [also known as the colon]). |
| Biopsy | The removal of a tissue sample for the purpose of examination. In coeliac disease, the tissue samples obtained from the small intestine, called duodenal biopsies, are examined under a microscope (i.e. histological examination) for evidence of active coeliac disease (e.g. villous atrophy). |
| Brain-gut axis (BGA) | The bi-directional relationship between the central nervous system and the gastrointestinal tract. The electrochemical process in the brain can influence the gut (e.g. passage of food, intestinal permeability), which may cause gastrointestinal symptoms (e.g. diarrhoea, constipation). Conversely, information from the gut (e.g. inflammation, microbial signals) can affect our thoughts, feelings, and behaviour. |
| Coeliac disease | A lifelong immune-mediated illness affecting the small bowel that emerges when a genetically susceptible individual ingests gluten. |
| Coeliac serology | The specific blood tests that measure antibodies in the bloodstream that can help in in the screening and diagnosis of coeliac disease. See deamidated gliadin peptide and transglutaminase below. |
| Cross contamination | When a gluten-free food/ingredient becomes contaminated by gluten due to contact with a gluten-containing food/ingredient. |
| Dapsone | A medication that can be used to treat the skin condition related to coeliac disease called dermatitis herpetiformis. |
| Deamidated gliadin peptide (DGP-IgG) | Antibodies to parts of gluten are produced in individuals with coeliac disease in response to dietary gluten intake. May be used as a screening test for coeliac disease. |
| Dermatitis herpetiformis | An extremely itchy rash composed of red bumps that affects a subset of people with coeliac disease. Treated with a gluten-free diet and Dapsone. |
| Duodenum | The first section of the small intestine (bowel), immediately after the stomach. To confirm a diagnosis of coeliac disease, the physician will conduct a gastroscopy to collect duodenal biopsies. |
| Endoscope | A long, flexible tube-like device with a video camera on the end. An endoscope is used to examine the digestive tract for signs of disease (e.g. gastroscopy). |
| False negative | Test results that erroneously indicates a condition/illness is not present, when in fact it is. |
| False positive | Test results that erroneously indicates a condition/illness is present, when in fact it is not. |
| Gastrointestinal | Relating to the digestive tract, that is, the organs that make up the passage beginning at the mouth and ending at the anus. |
| Gastroscopy | A procedure wherein an endoscope is inserted through the mouth to examine the upper gastrointestinal tract. In coeliac disease, the endoscope traverses the stomach and into the first section of the small bowel, the duodenum, where biopsies are collected. |
| Gluten |
A composite of water insoluble proteins found in wheat, barley, rye, and oats. These proteins are toxic to people with coeliac disease. (Note. Avoidance of oats is recommended in Australian and New Zealand. For people with coeliac disease in Europe and the US it is OK to have contamination free oats.) |
| Gluten-free | Containing no gluten. For food labelling, regulatory bodies define this as no detectable gluten (Australia, New Zealand) or gluten below a threshold of 20 parts per million [ppm] (e.g. in Europe and the USA). |
| HLA | Human leukocyte antigen (HLA) refers to a set of genes that influence how the immune system recognises foreign proteins. Some HLA genes impart genetic susceptibility to coeliac disease (see HLA-DQ2 and HLA-DQ8). |
| HLA-DQ2 and/or HLA-DQ8 | Almost every person with coeliac disease has one or both of these HLA gene types and their absence makes a diagnosis of coeliac disease very unlikely. Most people with these HLA gene types will not develop coeliac disease. |
| IgA Endomysial antibody (EMA) | A highly specific antibody test for coeliac disease. Less commonly used than tTG-IgA or DGP-IgG. |
| Mucosal healing | Healing of the lining of the small bowel. This is an important goal of treating coeliac disease and is generally achieved by strict adherence to gluten-free diet. |
| Non-coeliac gluten sensitivity | A term used to describe a condition wherein symptoms related to gluten ingestion are reported by individuals in which coeliac disease has been excluded as a potential cause. |
| Small bowel/small intestine | The section of the digestive tract between the stomach and the large bowel (or colon). The small bowel is the main organ affected in coeliac disease. |
| Tissue transglutaminase IgA antibodies (tTG-IgA) | Antibodies to transglutaminase (tTG) are produced in individuals with coeliac disease in response to dietary gluten intake. May be used as a screening test for coeliac disease. tTG-IgA assessment may be conducted with the deamidated gliadin peptide (DGP-IgG) test or the total serum IgA test. |
| Total serum IgA | A test that measures IgA antibody levels. These antibodies can be reduced in 3% of patients with coeliac disease, rendering tTG-IgA screening for coeliac disease inaccurate. If total IgA is reduced then the DGP-IgG test should be used. |
| Villi | The microscopic finger-like projections lining the inside of the small bowel that help increase the surface area for absorption of nutrients. |
| Villous atrophy | The flattening of the villi in the small bowel. In coeliac disease, the villi become damaged due to the body’s abnormal immune reaction to gluten. |