Celiac Disease
Overview
Celiac disease is a digestive disease that damages the small intestine and interferes with absorption of nutrients from food. People who have celiac disease cannot tolerate gluten, a protein in wheat, rye, and barley. Gluten is found mainly in foods but may also be found in everyday products such as medicines, vitamins, and lip balms.
When people with celiac disease eat foods or use products containing gluten, their immune system responds by damaging or destroying villi – the tiny, fingerlike protrusions lining the small intestine. Villi normally allow nutrients from food to be absorbed through the walls of the small intestine into the bloodstream. Without healthy villi, a person becomes malnourished, no matter how much food one eats.
Celiac disease is both a disease of malabsorption – meaning nutrients are not absorbed properly – and an abnormal immune reaction to gluten. Celiac disease is also known as celiac sprue, nontropical sprue, and gluten-sensitive enteropathy. Celiac disease is genetic, meaning it runs in families. Sometimes the disease is triggered – for becomes active for the first time – after surgery, pregnancy, childbirth, viral infection, or severe emotional stress.
How common is celiac disease?
Celiac disease affects people in all parts of the world. Originally thought to be a rare childhood syndrome, celiac disease is now known to be a common genetic disorder. More than 2 million people in the United States have the disease, or about 1 in 133 people. Among people who have a first-degree relative – a parent, sibling, or child – diagnosed with celiac disease, as many as 1 in 22 people may have the disease.
Celiac disease is also more common among people with other genetic disorders including Down syndrome and Turner syndrome, a condition that affects girls' development.
Source: National Digestive Diseases Information Clearinghouse (NDDIC)
Symptoms
Symptoms of celiac disease vary from person to person. Symptoms may occur in the digestive system or in other parts of the body. Digestive symptoms are more common in infants and young children and may include
• abdominal bloating and pain
• chronic diarrhea
• vomiting
• constipation
• pale, foul-smelling, or fatty stool
• weight loss
Irritability is another common symptom in children. Malabsorption of nutrients during the years when nutrition is critical to a child's normal growth and development can result in other problems such as failure to thrive in infants, delayed growth and short stature, delayed puberty, and dental enamel defects of the permanent teeth.
Adults are less likely to have digestive symptoms and may instead have one or more of the following:
• unexplained iron-deficiency anemia
• fatigue
• bone or joint pain
• arthritis
• bone loss or osteoporosis
• depression or anxiety
• tingling numbness in the hands and feet
• seizures
• missed menstrual periods
• infertility or recurrent miscarriage
• canker sores inside the mouth
• an itchy skin rash called dermatitis herpetiformis
People with celiac disease may have no symptoms but can still develop complications of the disease over time. Long-term complications include malnutrition – which can lead to anemia, osteoporosis, and miscarriage, among other problems – liver diseases, and cancers of the intestine.
Why are celiac disease symptoms so varied?
Researchers are studying the reasons celiac disease affects people differently. The length of time a person was breastfed, the age a person started eating gluten-containing foods, and the amount of gluten-containing foods one eats are three factors thought to play a role in when and how celiac disease appears. Some studies have shown, for example, that the longer a person was breastfed, the later the symptoms of celiac disease appear.
Symptoms also vary depending on a person's age and the degree of damage to the small intestine. Many adults have the disease for a decade or more before they are diagnosed. The longer a person goes undiagnosed and untreated, the greater the chance of developing long-term complications.
What other health problems do people with celiac disease have?
People with celiac disease tend to have other diseases in which the immune system attacks the body's healthy cells and tissues. The connection between celiac disease and these diseases may be genetic. They include
• type 1 diabetes
• autoimmune thyroid disease
• autoimmune liver disease
• rheumatoid arthritis
• Addison's disease, a condition in which the glands that produce critical hormones are damaged
• Sjögren's syndrome, a condition in which the glands that produce tears and saliva are destroyed
Source: National Digestive Diseases Information Clearinghouse (NDDIC)
Causes
Celiac disease is activated in genetically susceptible individuals by the dietary ingestion of "gluten". Although the disease activating proteins in wheat, rye and barley that activate celiac disease are popularly termed "gluten", strictly speaking, gluten is only present in wheat and the more scientific terms for the disease activating proteins in rye and barley, respectively, are secalins and hordeins. Wheat gluten is a combination of gliadins and glutenins. Gliadins, glutenins as well as hordeins, and secalins all characteristically have a high proline and glutamine content. For convenience and because of its widespread use, the disease activating proteins will be mostly referred to on this website as "gluten".
Gluten is resistant to proteolytic digestion by gastric, pancreatic, and brush border enzymes in the intestine. This is because there is a relative lack of enzymes with prolyl endopeptidase activity in human small intestine. As a result there are many relatively large peptides of gluten in the small intestine that have not been fully digested. Tissue transglutaminase, an enzyme produced by cells in the intestinal mucosa, and that is activated during tissue injury, can convert some of the glutamine residues in these peptides to glutamic acid. This increases the binding of those peptides to the celiac disease associated HLA–DQ2 and –DQ8 molecules on cells in the mucosa that can then activate populations of gluten specific CD4+ T cells that produce gamma interferon. Those T cells in combination with other populations of lymphocytes that are present within the epithelial lining (i.e., intraepithelial lymphocytes) cause tissue damage, leading to a loss of the absorptive surface. Current thinking is that both acquired and innate immune mechanisms are important contributors to the pathogenesis of celiac disease.
Source: Wm. K. Warren Medical Research Center for Celiac Disease
Prevention
Because the exact cause is unknown, there is no known way to prevent the development of celiac disease. However, being aware of the risk factors (such as having a family member with the disorder) may increase your chances of early diagnosis, treatment, and a long, healthy life.
Diagnosis
Recognizing celiac disease can be difficult because some of its symptoms are similar to those of other diseases. Celiac disease can be confused with irritable bowel syndrome, iron-deficiency anemia caused by menstrual blood loss, inflammatory bowel disease, diverticulitis, intestinal infections, and chronic fatigue syndrome. As a result, celiac disease has long been underdiagnosed or misdiagnosed. As doctors become more aware of the many varied symptoms of the disease and reliable blood tests become more available, diagnosis rates are increasing.
Blood Tests
People with celiac disease have higher than normal levels of certain autoantibodies—proteins that react against the body's own cells or tissues—in their blood. To diagnose celiac disease, doctors will test blood for high levels of anti-tissue transglutaminase antibodies (tTGA) or anti-endomysium antibodies (EMA). If test results are negative but celiac disease is still suspected, additional blood tests may be needed.
Before being tested, one should continue to eat a diet that includes foods with gluten, such as breads and pastas. If a person stops eating foods with gluten before being tested, the results may be negative for celiac disease even if the disease is present.
Intestinal Biopsy
If blood tests and symptoms suggest celiac disease, a biopsy of the small intestine is performed to confirm the diagnosis. During the biopsy, the doctor removes tiny pieces of tissue from the small intestine to check for damage to the villi. To obtain the tissue sample, the doctor eases a long, thin tube called an endoscope through the patient's mouth and stomach into the small intestine. The doctor then takes the samples using instruments passed through the endoscope.
Dermatitis Herpetiformis
Dermatitis herpetiformis (DH) is an intensely itchy, blistering skin rash that affects 15 to 25 percent of people with celiac disease. The rash usually occurs on the elbows, knees, and buttocks. Most people with DH have no digestive symptoms of celiac disease.
DH is diagnosed through blood tests and a skin biopsy. If the antibody tests are positive and the skin biopsy has the typical findings of DH, patients do not need to have an intestinal biopsy. Both the skin disease and the intestinal disease respond to a gluten-free diet and recur if gluten is added back into the diet. The rash symptoms can be controlled with antibiotics such as dapsone. Because dapsone does not treat the intestinal condition, people with DH must maintain a gluten-free diet.
Screening
Screening for celiac disease means testing for the presence of autoantibodies in the blood in people without symptoms. Americans are not routinely screened for celiac disease. However, because celiac disease is hereditary, family members of a person with the disease may wish to be tested. Four to 12 percent of an affected person's first-degree relatives will also have the disease.
Source: National Digestive Diseases Information Clearinghouse (NDDIC)
Prognosis
Following a gluten-free diet heals the damage to the intestines and prevents further damage. This healing most often occurs within 3 - 6 months in children, but it may take 2 - 3 years in adults.
Rarely, long-term damage will be done to the lining of the intestines before the diagnosis is made.
Some problems caused by celiac disease may not improve, such as a shorter than expected height and damage to the teeth.
Treatment
1. Obtain information about a gluten-free diet
A strict gluten-free diet is advised for life.
Referral to an experienced nutritionist:
This is an often-quoted initial post diagnosis management issue. Unfortunately, this is often an unrewarding experience for a patient because there are only a few dieticians/nutritionists very experienced in the gluten-free diet. These persons usually practice in Medical Centers with an interest in treating patients with celiac disease or may in fact have the disease.
Physicians should familiarize themselves with some of the difficulties encountered by patients in trying to obtain the perfect gluten-free diet. Patients often feel that after diagnosis they are left out on a limb. They receive instructions like "go to the Internet" or are referred to dieticians with little knowledge of the diet.
When patients are quite ill they are advised to eat a few safe foods, for example rice, baked potato, meat without condiments, and cooked vegetables. They should gradually diversify their diet as their knowledge base about a gluten- free diet increases. Eating commercially prepared food and at restaurants should initially be avoided.
We have gathered together information as to the basic gluten-free diet (read more).
Referral to National and Local Celiac Support groups:
Most patients obtain information from support groups. Local support groups provide such resources as accompanying newly diagnosed individuals on shopping excursions. These local groups are often affiliated with the National support groups. The Internet provides another important recourse. Unfortunately, not all the information is scientifically sound.
2. Assessment of nutritional deficiencies
Serum ferritin as a parameter of iron stores, folate and vitamin B12 levels need to be measured. When deficient, iron should be prescribed. Folic acid and vitamin B12 should be given only if blood levels are low. Vitamin B12 needs to be given by injection. Serum albumin and calcium need to be measured.
A multivitamin and calcium supplements are reasonable for most patients, but benefit has not been assessed in any study.
3. Check that medications are gluten-free
Because medications are taken on a regular basis, often at several times through a day, patients are advised to ensure that they are gluten free. This is usually accomplished by calling the drug manufacturer.
4. Obtain bone density determination
Bone density is frequently reduced in patients with celiac disease and results in increased fracture risk. Bone density should be determined at the wrist, spine and hip. If there are reduced levels of parathyroid hormone, calcium and vitamin D should be measured. Vitamin D needs to be administered if levels are low.
Treatment of reduced bone density in celiac disease consists of calcium supplements, with or without vitamin D, together with a gluten free diet. On this regime bone density will usually increase. Bone anti-resorption agents (for example Fosamax) have not been studied in patients with celiac disease. They potentially can cause a fall in serum calcium if administered when a patient has active celiac disease and should be reserved for patients who still have reduced bone density after an adequate period on calcium and a gluten-free diet.
5. Pneumovax administration
Hyposplenism, or an inadequately functioning spleen, is common in active celiac disease. Because the spleen is important in fighting bacterial infections caused by pneumococcal bacteria, patients over the age of 50 years are advised to have the pneumococcal vaccine. This is usually repeated every 5 years.
6. Screen family members
First degree relatives are advised to be screened. This is because the disease is common, about 1 in 10 family members have the disease, and it is considered that early diagnosis prevents the development of associated autoimmune diseases, osteoporosis and symptomatic celiac disease.
7. Monitor serum antibody levels
Patients are advised to have follow-up antibody levels measured at 6 and 12 months. Most patients have normal levels by that time though it may take up to 3 years to normalize in some individuals. It is reasonable to assess antibody levels annually. This will serve to monitor adherence to the diet though is not sensitive for minor dietary indiscretions
8. Repeat duodenal biopsy
A repeat biopsy is frequently performed to assess response to the diet, though it is not necessary for conformation of the diagnosis of celiac disease. Some experts recommend a biopsy during the first 6 months after diagnosis. However, if a patient is doing well on the diet, a repeat biopsy early in the course of the diet will serve little purpose. The biopsy may not show sufficient improvement. We recommend a follow up biopsy at about 2 to 3 years to assess optimal improvement. While many patients will have normal biopsies on these follow up procedures, some patients have persistent villous atrophy. This may be due to ongoing gluten ingestion.
Patients who are not doing well on the diet, due to persistent abdominal complaints or diarrhea, may undergo earlier, or more frequent endoscopy and biopsy to assess the status of the celiac disease, or whether there are other complicating conditions such as collagenous sprue or refractory sprue.
9. General health measures
Patients need to be aware that they are at somewhat increased risk to develop obesity and elevated cholesterol levels on the diet. This is probably due to several reasons. Gluten-free food may have more calories than regular food and absorption of food becomes more efficient in patients with celiac disease once this is treated with a gluten-free diet. Many patients are already overweight at diagnosis; this will obviously become a greater problem for these individuals. For some patients, elevation of the serum cholesterol also becomes a problem. This should be monitored and treated appropriately by diet and occasionally with medications.
10. Screening for malignancies
Patients with celiac disease are at an increased risk for the development of some specific types of malignancies. A gluten-free diet is considered protective. After diagnosis and commencement of the gluten-free diet, the increased rates in most studies fall to that of the general population.
There are currently no recommended guidelines for screening individuals with celiac disease for malignancies. It would seem prudent for patients to at least have an annual thorough physical examination and to have the stool examined for occult blood.