Celiac disease
Celiac disease is an autoimmune disorder affecting the digestive system, specifically the small intestine, where ingestion of gluten leads to damage of the intestinal villi, which are essential for nutrient absorption. This condition often results in malnutrition, as individuals may struggle to absorb essential nutrients from their diet. Risk factors include a family history of the disease and the presence of other autoimmune disorders. The disease can manifest at any age, with symptoms varying significantly between children and adults. Common symptoms include digestive issues like abdominal pain and chronic diarrhea in children, and non-digestive symptoms such as anemia, fatigue, and depression in adults. Diagnosis typically involves a combination of medical history, blood tests, and biopsies to confirm intestinal damage. The only effective treatment is a strict lifelong gluten-free diet, which can alleviate symptoms and promote healing of the intestine, though following this diet can be complex and requires careful management. Early diagnosis and adherence to dietary restrictions are crucial for minimizing long-term health complications.
Celiac disease
DEFINITION Celiac disease is an autoimmune disease of the digestive tract. For patients with celiac disease, eating food with gluten damages small protrusions in the small intestine. These protrusions, called villi, absorb nutrients from foods. The condition affects absorption of all nutrients. Untreated patients often become malnourished.
ALSO KNOWN AS: Celiac sprue; nontropical sprue; gluten-sensitive enteropathy
Risk Factors
Individuals whose family members have celiac disease are at risk for the illness. Individuals also are at risk if they have a history of another autoimmune disease, such as type 1 diabetes, autoimmune thyroid disease, lupus, dermatitis herpetiformis (a skin condition associated with celiac disease), and rheumatoid arthritis.
Etiology and Genetics
Celiac disease is a complex disorder that is determined by an interaction between both genetic and environmental components. According to researchers Francesca Megiorni and Antonio Pizzuti in 2012, 90 to 95 percent of affected individuals have at least one allele heterodimer (protein consisting of two different macromolecules) of two closely linked predisposing genes found at the major histocompatibility locus on the short arm of chromosome 6, at position 6p21.32. These alleles, known as HLA-DQA1 and HLA-DQB1, most commonly form the heterodimers DQ2.5 and DQ8. The HLA (human leukocyte antigen) alleles are necessary but not sufficient to predispose the development of celiac disease, since some unaffected individuals also carry one or both of them.
Additionally, there are several other regions in the genome that are unlinked to the HLA region and that may contain genes for celiac disease susceptibility (at positions 1q31, 2q11, 2q33, 3q21, 3q25, 3q28, 4q27, 5q31, 12q24, 15q11, and 19p13.1). Each of these has a relatively weak effect in comparison to the HLA alleles, but they serve to complicate the inheritance patterns and make predictions of outcomes more unreliable.
The incidence of celiac disease in first-degree relatives of affected individuals could be as high as 44 percent, according to various studies. Concordance rates for celiac disease in identical twins have been reported to be about 83 to 85 percent, according to Megiorni and Pizzuti. By contrast, the prevalence among the general US population was about 1 in 133 people in 2020. Like most autoimmune disorders, it is more often diagnosed in women.
The environmental factors that may serve to trigger the development of the disease are also not well understood, although a diet high in gluten is certainly a prerequisite. Other contributing environmental factors that have been reported include stress, pregnancy, traumatic injury, surgery, and systemic infections.
Symptoms
Symptoms of celiac disease vary and may start in childhood or adulthood. Children often have different symptoms from adults. Symptoms may not develop if a large section of the intestine is undamaged. Malnutrition may produce the first signs of the condition, which are often the most serious.
Digestive signs and symptoms of celiac disease in children may include abdominal pain, nausea, decrease in appetite, vomiting (in later stages of the disease), chronic diarrhea or constipation, and malodorous, pale, or fatty stools. The inability to absorb nutrients can also lead to symptoms such as anemia, slowed growth, short stature, delayed puberty, weight loss, irritability or mood swings, damage to the enamel of permanent teeth, neurological symptoms or disorders, and failure to thrive (in infants).
Digestive symptoms are less common in adults than in children. When present, these symptoms may include abdominal pain and bloating, ulcers, and intestinal blockages. More common, non-digestive signs and symptoms in adults include anemia, headaches, fatigue, bone or joint pain, depression or anxiety, seizures, missed menstrual periods, infertility or repeated miscarriages, canker sores or dry mouth, dermatitis herpetiformis, tingling numbness in extremities, and osteoporosis (loss of bone density) or osteomalacia (softening of the bone). According to a study published by Sujata P. Thawani and colleagues in JAMA Neurology in 2015, persons with celiac disease are also more likely to develop nerve damage.
Screening and Diagnosis
The doctor will ask about an individual’s symptoms and medical history and will conduct a physical exam. Symptoms of celiac disease are similar to those of other conditions. It may take a long time to get a diagnosis. Early diagnosis and treatment reduce the risk of complications.
Tests may include blood tests to detect the presence of gluten antibodies (produced by the immune system) and to look for evidence of malabsorption (anemia, vitamin and mineral deficiencies). Stool tests can also check for evidence of malabsorption. Other tests include endoscopy, in which a thin, lighted tube is inserted down the throat to examine the intestine; biopsy, in which a small sample of tissue is removed during endoscopy to test for inflammation and tissue damage; and repeat biopsy, a biopsy performed several weeks after treatment begins to confirm the diagnosis.
Treatment and Therapy
A lifelong gluten-free diet is the only known treatment for celiac disease. Fortunately, it is very effective, and symptoms usually go away within days of starting the diet. Healing of the villi (singular: villus) may take months or years. Additional intake of gluten can damage the intestine, even if the patient has no symptoms. Delayed growth and tooth discoloration may be permanent. Intravenous nutritional supplements may be needed if the intestinal damage is significant and does not heal. Since gluten is added to many foods, following a gluten-free diet can be complicated and often frustrating. Some patients find support groups helpful.
Individuals with celiac disease must avoid all foods containing wheat, rye, or barley. This includes most bread, pasta, cereal, and processed foods. Special gluten-free breads and pastas are available; they are made with potato, rice, soy, or bean flour. Patients who are lactose intolerant before their small intestine heals should avoid milk products. A dietitian can assist patients with meal planning.
Gluten is found in some unexpected foods and beverages; patients should carefully read all labels. Other foods containing gluten include flavored coffee, beer, tuna in vegetable broth, packaged rice mixes, some frozen potatoes, creamed vegetables, commercially prepared vegetables, salads and salad dressings, pudding, some ice cream, and many other products. Ordering at restaurants can be especially challenging, since many foods on the menu may surprisingly contain gluten.
Patients with celiac disease should be tested for nutritional deficiencies. Bone density testing may also be needed. If vitamin or mineral deficiencies are found, the doctor may recommend taking supplements. Once the disease is under control with a gluten-free diet, however, this is often not necessary.
Prevention and Outcomes
There are no guidelines for preventing celiac disease because the cause is not understood. If celiac disease runs in an individual’s family, that individual should ask the doctor about a screening test. The earlier patients start the gluten-free diet, the less damage there will be to their intestines.
Bibliography
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Thawani, Sujata P., et al. "Risk of Neuropathy among 28,232 Patients with Biopsy-Verified Celiac Disease." JAMA Neurology, vol. 72, no. 7, 2015, pp. 806–11. MEDLINE Complete, search.ebscohost.com/login.aspx?direct=true&db=mdc&AN=25962148&site=ehost-live. Accessed 5 Dec. 2017.