Celiac disease
Celiac disease is defined as "a malabsorption syndrome that is precipitated by the ingestion of gluten-containing foods, such as wheat, rye, and barley.[1][2] It is characterized by inflammation of the small intestine, loss of microvilli structure, failed intestinal absorption, and malnutrition." 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.
Etiology / cause
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.
Gluten may cause symptoms in people without Celiac disease.[3][4]
Epidemiology
Celiac disease occurs in about 1% of the United States of America.[5]
Signs and symptoms
Celiac disease is hard to diagnose without a specific test. Celiac disease may have a rash of dermatitis herpetiformis. 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
- non-ulcer dyspepsia[6]
- 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 clinical 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).[7]
Blood tests
| Test | sensitivity | specificity |
|---|---|---|
| AGA IgA | 50% | 98% |
| AGA IgA | 25% | 98% |
| Anti-EMA | 81% - 90% | 99% |
| Anti-TGA (anti-TTG) | 81% - 89% | 99% |
| Notes: 1. AGA = gliadin antibodies 2. EMA = endomysium antibodies 3. TGA = (tissue) transglutaminase antibodies | ||
Antibody testing
IgA antiendomysial antibodies can detect celiac disease with a sensitivity and specificity of 90% and 99% according to a systematic review. The systematic review estimates that the prevalence of celiac disease in primary care patients with gastrointestinal symptoms to be about 3%. This results in a positive predictive value of and a negative predictive value of 74% and negative predictive value of 3% (click here to recalculate for different prevalences of celiac disease).[10] The review found that IgA antitissue transglutaminase antibodies performs similarly, but is an easier test to perform.
HLA genetic typing
| Test | sensitivity | specificity |
|---|---|---|
| HLA-DQ2 | 94% | 73% |
| HLA-DQ8 | 12% | 81% |
Antibody testing and HLA testing have similar accuracies.[9]
Other diagnostic tests
Some professional guidelines recommend screening of all patients for osteoporosis by DXA/DEXA scanning.[11][12]
References
- ↑ National Library of Medicine. Celiac disease. Retrieved on 2007-11-27.
- ↑ Green PH, Cellier C (2007). "Celiac disease". N. Engl. J. Med. 357 (17): 1731–43. DOI:10.1056/NEJMra071600. PMID 17960014. Research Blogging.
- ↑ Biesiekierski JR, Newnham ED, Irving PM, Barrett JS, Haines M, Doecke JD et al. (2011). "Gluten causes gastrointestinal symptoms in subjects without celiac disease: a double-blind randomized placebo-controlled trial.". Am J Gastroenterol 106 (3): 508-14. DOI:10.1038/ajg.2010.487. PMID 21224837. Research Blogging.
- ↑ Carroccio A, Mansueto P, Iacono G, Soresi M, D'Alcamo A, Cavataio F et al. (2012). "Non-celiac wheat sensitivity diagnosed by double-blind placebo-controlled challenge: exploring a new clinical entity.". Am J Gastroenterol 107 (12): 1898-906. DOI:10.1038/ajg.2012.236. PMID 22825366. Research Blogging.
- ↑ Katz KD, Rashtak S, Lahr BD, Melton LJ, Krause PK, Maggi K et al. (2011). "Screening for Celiac Disease in a North American Population: Sequential Serology And Gastrointestinal Symptoms.". Am J Gastroenterol 106 (7): 1333-9. DOI:10.1038/ajg.2011.21. PMID 21364545. PMC PMC3130886. Research Blogging.
- ↑ Ozaslan E, Akkorlu S, Eskioğlu E, Kayhan B (2007). "Prevalence of silent celiac disease in patients with dyspepsia". Dig. Dis. Sci. 52 (3): 692–7. DOI:10.1007/s10620-006-9453-1. PMID 17235704. Research Blogging.
- ↑ 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. DOI:10.1136/bmj.39133.668681.BE. PMID 17383983. Research Blogging.
- ↑ van der Windt, Danielle A. W. M.; Petra Jellema, Chris J. Mulder, C. M. Frank Kneepkens, Henriette E. van der Horst (2010-05-05). "Diagnostic Testing for Celiac Disease Among Patients With Abdominal Symptoms: A Systematic Review". JAMA 303 (17): 1738-1746. DOI:10.1001/jama.2010.549. Retrieved on 2010-05-05. Research Blogging.
- ↑ 9.0 9.1 9.2 Hadithi M, von Blomberg BM, Crusius JB, et al (2007). "Accuracy of serologic tests and HLA-DQ typing for diagnosing celiac disease". Ann. Intern. Med. 147 (5): 294–302. PMID 17785484. [e]
- ↑ van der Windt DA, Jellema P, Mulder CJ, Kneepkens CM, van der Horst HE (2010). "Diagnostic testing for celiac disease among patients with abdominal symptoms: a systematic review.". JAMA 303 (17): 1738-46. DOI:10.1001/jama.2010.549. PMID 20442390. Research Blogging.
- ↑ (2001) "American Gastroenterological Association medical position statement: Celiac Sprue". Gastroenterology 120 (6): 1522–5. PMID 11313323. [e]
- ↑ P Ciclitira , “Interim Guidelines for the Management of Patients with Coeliac Disease.,” British Society of Gastroenterology, April 2002, (accessed October 12, 2007).