Celiac Disease (Gluten Enteropathy)

Celiac disease is a digestive disorder that occurs in reaction to gluten, a protein found in rye, barley, wheat, and hundreds of foods made with these grains.

Celiac disease is thought to be an autoimmune disorder and may have a familial or genetic component. In people with celiac disease, inflammation occurs in the small intestinal mucosa when it is exposed to gluten in the diet. Celiac disease is also known by other names including celiac sprue, non-tropical sprue, and gluten enteropathy.

Gluten is a protein found in wheat, barley, and rye. In some people who are exposed to gluten in their diet, an enzyme called tissue transglutaminase changes the gluten into a chemical that causes an immune response, leading to inflammation of the lining of the small intestine. The normal finger-like projections (villi) that make up the lining of the intestine are blunted and destroyed, preventing the normal absorption of nutrients from the diet.

This malabsorption of vitamins, minerals, and other nutrients may lead to damage to other organs in the body, such as the liver, bone, and brain that depend on those nutrients to develop and function normally. In children, the lack of effective nutrition because of malnutrition may cause abnormal growth and development.

There seems to be a genetic predisposition to developing celiac disease, however, not all people with a family history of celiac disease develop the condition. There may be another reason, yet discovered as to why the autoimmune response occurs.

In addition to family history, celiac disease seems to be more common in people with the following:

• Type 1 diabetes
• Microscopic colitis
• Sjögren's syndrome
• Autoimmune thyroid disease

Diarrhea and weight loss because of malabsorption are the classic symptoms of celiac disease, but they occur in less than one-half of people with the disease. The symptoms vary widely in presentation and intensity. Often the symptoms are not related to the bowel function, but instead are due to the consequences of chronic malabsorption of vitamins and minerals, for example, people who complain of weakness, fatigue, joint pain, and are anemic (low blood cell count) because they cannot absorb iron in the diet.

Other symptoms of celiac disease may include the following:

• Headache
• Fatigue and weakness
• Joint pain
• Numbness and tingling (paresthesia) of the hands and feet
• Osteoporosis due to decreased absorption of calcium and vitamin D
• Skin rash
• Abdominal pain
• GERD and heartburn

Infants and children may have even less specific symptoms including diarrhea, constipation, weight loss, failure to thrive, and developmental delays.

The diagnosis of celiac disease is often delayed and it may take several months or years for the patient and the doctor to think of it as the cause of its many nonspecific symptoms. History and physical examination may give direction as to the diagnosis, but commonly it takes many visits with the patient complaining of recurrent abdominal pain, nonspecific joint aches, or demonstrating chronic anemia that does not respond to iron treatment, to raise the suspicion that celiac disease is a possibility.

When the diagnosis is suspected, there is a two-step screening process to make the diagnosis:

1. Blood test for immunoglobulin A anti-tissue transglutaminase antibody (IgA TTG). Testing for antiendomysial antibodies may also be considered.
2. If the screening blood test is positive, then endoscopy and biopsy of the lining of the duodenum (the first part of the small intestine) is recommended. Usually performed under sedation, a fiberoptic tube is passed through the mouth, through the esophagus and stomach into the duodenum, and a small bit of tissue is taken to be examined under a microscope.

The patient must eat a regular diet for many weeks before the testing procedures. If the patient has already started a gluten-free diet, it may cause the tests to be falsely negative.

Once the diagnosis is made, screening for osteoporosis may be appropriate.

Since it is often familial, once one person in the family is diagnosed with celiac disease, it is reasonable to have other close family members screened.

Currently, the only treatment for celiac disease and the inflammation of the small intestine caused by gluten protein exposure is a lifelong gluten-free diet.

What is latent celiac disease, and how is it treated?

Latent or potential celiac disease describes those people suspected of having the disease with a positive antibody blood test, but whose small bowel biopsy is normal. Currently, there is no indication to begin treatment with a gluten-free diet, however, a repeat biopsy might be considered if signs and symptoms develop or if symptoms of malabsorption are present.

What is silent celiac disease, and how is it treated?

Individuals may be screened for celiac disease and have both a positive antibody blood test and a positive small intestine biopsy, and yet have no symptoms. This is considered silent celiac disease and the recommendation is to perform further testing to look for malabsorption complications such as anemia and osteoporosis. A gluten-free diet may be indicated if these tests are positive.

What is refractory celiac disease, and how is it treated?

While a gluten-free diet tends to resolve symptoms in most individuals, in a small group of patients, the gluten-free diet fails to control the symptoms including abdominal pain and malabsorption. These patients are considered refractory to diet treatment. Other types of bowel disease, including Crohn's disease must be first excluded before making this diagnosis. If diet therapy fails to resolve symptoms, refractory celiac disease is often treated with the same medications used in other autoimmune disorders to decrease inflammation. These medications include corticosteroids (prednisone), azathioprine (Imurarn, Azasan), and cyclosporine.

Gluten is a complex protein found in wheat, barley, and rye grains. A gluten-free diet excludes exposure to any of the foods that have this protein in their ingredients. It is easy to understand that regular wheat bread or pizza dough has gluten in it. However, it is less easy to realize that wheat flour is often used in many processed foods and in recipes for many foods that are prepared in a restaurant. Moreover, for it to be considered completely gluten-free, processed foods should be prepared in a kitchen or factory that has no cross-contamination with grains containing gluten.

The Federal Drug Administration has published new guidelines that define gluten-free food as having less than 20 parts per million of gluten. Regulations regarding food-labeling criteria require food to meet this standard to be labeled "gluten-free." It is important to read the labels for all food products. Aside from a gluten-free designation, there may be food allergy statements that discuss the factory or kitchen where the product was manufactured.

Many restaurants have gluten-free menus or can accommodate the gluten-free dietary needs of their customers, but the person needs to ask the server, manager, or cook directly about whether it contains gluten.

The inability to properly absorb vitamins, minerals, and nutrients from the diet can affect many organs in the body. Since the diagnosis of celiac disease is often delayed, there can be significant issues with iron deficiency anemia, osteoporosis because of decreased levels of calcium and vitamin D, and poor growth and development.

Aside from the other associated autoimmune disorders that might also be present, celiac disease is associated with an increased incidence of lymphoma and small intestine cancer. This risk is reduced in patients who maintain a strict gluten-free diet.

Celiac disease is thought to be an autoimmune disorder, meaning that the body develops antibodies against its tissues. Researchers believe that other diseases may be related, and may affect organs such as the thyroid (autoimmune thyroiditis), the liver (primary biliary cirrhosis), and the colon (microscopic colitis). Other diseases may include type 1 diabetes and dermatitis herpetiformis, a skin rash that has similar antibodies as celiac disease, but that is found in the skin.

Growth failure, delayed puberty, miscarriage, and infertility may be associated with celiac disease.