Celiac disease (CD) is a chronic (long-term) digestive disease during which patients have irritation (inflammation) of the small intestine, which causes difficulty with absorbing nutrients from food. Patients with CD often have other family members with the condition and are therefore susceptible to this disease. Inflammation in the intestine occurs when a patient with CD begins to eat food that contains gluten. Gluten is the name given to certain types of proteins found in wheat, barley, rye and related grains. Oats are currently considered not to be dangerous to persons with CD. However, due to the high possibility of contamination with other gluten containing grains, oats are typically not recommended for people with celiac disease. When food containing gluten arrives in the small intestine, the immune system reacts against the gluten, causing an inflammatory reaction in the wall of the intestine. The small intestine lining is covered by millions of villi, finger-like projections that act to increase the surface area of the intestine allowing increased absorption of nutrients. The villi are damaged by the inflammation in CD, which results in a decrease in the absorption of food. When gluten is removed from the diet, inflammation is reduced and the intestine begins to heal. The time when a patient develops symptoms varies from patient to patient after their first contact with the gluten protein. In many cases, it may be decades before symptoms and signs develop, often precipitated by a trigger.
What are the symptoms of celiac disease?
The symptoms or signs of celiac disease are highly variable. Some people have mild inflammation with few symptoms. Even though they may feel quite well, there is still damage occurring to the lining of the intestine. Other people have more severe inflammation, which causes symptoms that may be severe enough to lead them to visit their doctor. Occasionally, individuals will not have any symptoms at all even though their small intestine is severely inflamed.
The most common symptoms and signs (consequences) are:
- Abdominal pains
- Bloating and gas
- Stools that may float or smell very bad
- Weight loss
- Poor growth or weight loss in children
- Anemia (low blood count)
Other symptoms and signs (consequences) are:
- Feeling weak
- Low vitamin levels—especially iron, calcium and folate
- Bone and joint pains
- Osteoporosis (bone thinning)
- A skin rash that lasts
- Infertility or reproductive difficulties
- Neurological deficits (neuropathy)
- Liver enzyme abnormalities
Someone with celiac disease may have a variety of the above symptoms, and different people with celiac disease may have completely different symptoms. Celiac disease can mimic the symptoms of more common problems and be misdiagnosed as irritable bowel syndrome (IBS). It is now recommended that patients with IBS symptoms such as abdominal pain and changes in bowel movements (especially diarrhea) be tested for celiac disease.
How do you screen or diagnose celiac disease?
It is important to remember that most patients with abdominal pain, bloating or diarrhea do not have celiac disease. In order to test for celiac disease with blood tests and/or endoscopy, the doctor should suspect celiac disease as the cause for the symptoms. When the doctor thinks that celiac disease is possible, but not very likely, then blood tests alone are done. If the blood tests are normal, other tests are rarely necessary. Sometimes the doctor strongly suspects that the symptoms are due to celiac disease or another similar illness, and will request an endoscopy and biopsy (sampling of the tissue of the small intestine). All tests for celiac disease, except for genetic tests, must be done while the patient is on a normal diet that contains gluten. Patients who are concerned that they may have celiac disease should not restrict their diet prior to seeking medical evaluation because this may cause false negative test results.
Specific antibody blood tests are used to diagnose patients with CD. These blood tests are also used to test people who may be at risk for having CD but have no symptoms (relatives of patients with CD). The 2 most accurate tests used are the endomysial antibody and tissue transglutaminase antibody tests. Other tests, such as tests for deamidated gliadin peptide antibodies, may be used in restricted circumstances, but are not as accurate because they can be abnormal in healthy patients who do not have celiac disease or in people with other digestive problems. The original anti-gliadin or anti-gluten tests are no longer used for the diagnosis of celiac disease. Other tests for allergies will not detect celiac disease. Tests on saliva or stool for antibodies are not good substitutes for the blood-based tests. Genetic tests are available to assist doctors when the blood tests are unclear, or when patients continue to have symptoms while on a gluten free diet. However, simply carrying the genes that enable celiac disease does not mean that the patient will get celiac disease, only that it is possible. Not having the genes is a very good way to rule out the possibility of having celiac disease and may be used when the certainty of diagnosis is in doubt.
Establishing a firm diagnosis of CD requires taking biopsy samples of the small intestine using endoscopy. Endoscopy involves insertion of a thin flexible tube through the mouth into the stomach and small intestine. Tiny samples are taken from the wall of the small intestine and are examined under a microscope for changes of CD. This test is usually performed with the aid of sedatives.
How do you treat celiac disease?
Celiac disease is treated by avoiding all foods that contain gluten. Gluten is what causes inflammation in the small intestine. When this is removed from the diet, the intestine will heal and return to normal. Dieticians with expertise in gluten-free diets are essential for educating patients and tailoring diets. Medications are not normally required to treat CD except in occasional patients who do not respond to a gluten-free diet. There are many CD support groups available for patients and family members.