Celiac disease
Celiac disease is an auto immune disorder that damages the small intestine and interferes with absorption of nutrients from food. In celiacs the immune system destroys the microvilli, small protrusions in the small intestine. Some researchers have estimated that 1 in 150 people may have some level of gluten sensitivity. Celiac disease has been called the most under diagnosed disease in the modern world.
Those with celiac disease cannot tolerate a protein called gluten, found in wheat, rye, and barley. Gluten proteins may also be found in products such as stamps and envelope adhesive. Celiacs can be so sensitive to gluten that they have to avoid products like hard candy that are often produced in molds that are dusted with flour to aid release.
Signs and symptoms
Celiac disease is hard to diagnose without a specific test. Symptoms caused by the lack of nutrient absorption are non-specific. Many diagnosed celiacs report that chronic symptoms have disappeared after just two weeks on a strict gluten free diet. Some reported symptoms include:
- chronic headaches
- irritable bowel syndrome
- lethargy
- depression
- attention deficit disorder
Diagnosis
There are several tests for celiac disease. A blood test can detect antibodies to gluten that indicate a sensitivity. However, the only way to make a certain diagnosis of celiac disease is to use and endoscope to take a sample of the wall of the small intestine and examine it under a microscope.
Combining findings into a prediction rule to guide use of endoscopy reported a sensitivity of 100% (it would identify all the cases) and specificity of 61% (it would be incorrectly positive in 39%). The prediction rule recommends that patients with high risk symptoms or positive serology should undergo endoscopy. The study defined high risk symptoms as weight loss, anaemia (haemoglobin less than 120 g/l in females and less than 130 g/l in males), or diarrhoea (more than three loose stools per day).[1]
Blood tests
Antibody testing
Serologic blood tests are useful in diagnosing celiac disease.
| Test | sensitivity | specificity |
|---|---|---|
| AGA IgA | 50% | 98% |
| AGA IgA | 25% | 98% |
| Anti-EMA | 81% | 99% |
| ATA (Anti-TTG) | 81% | 99% |
| Test | sensitivity | specificity |
|---|---|---|
| HLA-DQ2 | 94% | 73% |
| HLA-DQ8 | 12% | 81% |
HLA genetic typing
Antibody testing and HLA testing have similar accuracies.[2]
Other diagnostic tests
Some professional guidelines[3] recommend screening of all patients for osteoporosis by DXA/DEXA scanning.
- ↑ Hopper A, Cross S, Hurlstone D, McAlindon M, Lobo A, Hadjivassiliou M, Sloan M, Dixon S, Sanders D (2007). "Pre-endoscopy serological testing for coeliac disease: evaluation of a clinical decision tool". BMJ 334: 729. PMID 17383983.
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