- Clinical science
Celiac disease, also referred to as celiac sprue or non-tropical sprue, is a common condition characterized by a maladaptive immune response to gluten, a protein found in many grains (e.g., wheat). The disease often occurs in patients with other autoimmune illnesses, as both are associated with HLA variants (human leukocyte antigens, which encode immunoregulatory proteins) that cause pathologically increased immune responses. The underlying pathophysiology is believed to be a combination of gluten intolerance, which triggers an autoimmune reaction, and production of autoantibodies that target tissue transglutaminase, specifically within the proximal small intestine. Typical findings include changes in bowel habits and symptoms associated with malabsorption (e.g., fatigue, weight loss, vitamin deficiencies). Diagnostic tests include the detection of various antibodies. To confirm the diagnosis, an endoscopic biopsy from the small intestine is needed. Histopathological findings often include villous atrophy and crypt hyperplasia. A firm diagnosis is necessary, as therapy involves a lifelong commitment to a gluten-free diet. If patients comply with this diet, the prognosis is generally very good and the increased risk of celiac-associated malignancies (e.g., intestinal lymphoma) is mitigated.
- Definition: an autoimmune disorder characterized by an intestinal hypersensitivity to gluten, a grain protein
- Synonyms for celiac disease include celiac sprue and gluten-sensitive enteropathy
- Sex: ♀ > ♂
Age of onset
- At 8–12 months (or 2–3 months following the first exposure to gluten through diet containing wheat)
- Third to fourth decade of life
- But can occur at any age
- Bimodal distribution:
- Prevalence: in the US ∼ 1:3000
- More common in individuals of northern European descent
Epidemiological data refers to the US, unless otherwise specified.
Genetic predisposition with association to HLA antigens
- Common: HLA-DQ2 (90–95%)
- Alternatively: HLA-DQ8 (5–10%)
- Consuming gliadin from grains such as wheat, rye, and barley leads to an autoimmune reaction within the small intestinal wall.
- Commonly associated with autoimmune diseases (see “Clinical features” below)
Symptoms occur when an individual who is genetically predisposed develops an immunological response to gliadin, an alcohol-soluble fraction of gluten.
- Consumption of food containing gluten → tissue transglutaminase is released; → modifies gliadin from gluten proteins → pathogenic T cells react to and are activated by modified gliadin → mediate chronic intestinal inflammation → epithelial damage resulting in villous atrophy, crypt hyperplasia, and loss of brush border → impaired resorption of nutrients in the small intestine → malabsorption symptoms
- Chronic or recurring diarrhea: steatorrhea
- Flatulence, abdominal bloating, and pain
- Lack of appetite
- Constipation (rarely)
Extraintestinal symptoms and associations
- symptoms: fatigue, weight loss, , , osteoporosis, hypocalcemia
- In children: failure to thrive, growth failure, delayed puberty
- Dermatologic associations: dermatitis herpetiformis
- Neuropsychiatric symptoms: peripheral neuropathies (numbness, burning and tingling of the hands and feet) , headache, ataxia, depression, irritability
- Gynecological associations: reduced fertility or infertility
- Endocrine associations: autoimmune thyroid disease, type 1 diabetes mellitus
- Associated chromosomal syndromes: Turner syndrome, Down syndrome
- Other associated conditions: autoimmune hepatitis, inflammatory bowel disease, rheumatoid arthritis, sarcoidosis, selective IgA deficiency
In both children and adults, mild or asymptomatic cases are more common than the classic presentation of the disease.
If celiac disease is suspected (based on the medical history and clinical features), serum antibodies may be tested. Ultimately, the diagnosis should be confirmed via biopsy.
Gold standard: IgA (anti‑)tissue transglutaminase antibody (tTG)
- The single recommended test to diagnose celiac disease.
- In addition to the initial diagnosis, also useful for follow-up.
- Quantitative IgA test: In the case of an IgA deficiency, patients are tested for IgG-based antibodies.
IgG deamidated gliadin peptide (DGP) indications:
- IgA deficiency
- Also the test of choice in children under the age of two
- Anti-endomysial antibody (EMA)
- Low urine d-xylose levels following
- Fat malabsorption can be detected by quantitative stool fat assays or qualitatively by fat stains (e.g., Sudan III stain)
Endoscopy with small intestine biopsy
- Confirmatory test
- At least five duodenal biopsies should be taken and histologically examined.
- Characteristic histological findings:
- Definition: : A disease characterized by chronic diarrhea with subsequent malabsorption in association with a stay in the tropics or subtropics.
- Epidemiology: : occurs in residents of the tropics and subtropics or in travelers returning from these areas (after trips lasting several weeks)
- Etiology: most likely caused by a bacterial infection that leads to structural damage of the intestinal mucosa
- Clinical findings
- Blood tests: megaloblastic anemia, hypoalbuminemia, hypocalcemia, vitamin D deficiency
- Serology for antibodies to rule out celiac disease (see “Diagnostics” above)
- Stool analysis
- Endoscopy of the small bowel and biopsy: villous atrophy, elongated crypts, presence of inflammatory cells (plasma cells, lymphocytes, eosinophils)
- Treatment: tetracycline in combination with folic acid for 3–6 months
- Definition: infection with the bacteria Tropheryma whipplei
- Epidemiology: very rare, mainly males 30–60 years of age
- Intestinal manifestations: malabsorption syndrome, abdominal pain
- Extraintestinal manifestations: enteropathic arthritis (60% of cases) , sacroiliitis (40% of cases), fever, polyserositis, lymphadenopathy, cardiac symptoms (e.g., valve insufficiencies), and neurological conditions (myoclonia, ataxia, impairment of oculomotor function)
The differential diagnoses listed here are not exhaustive.
Lifelong gluten-free diet
- Abstain from products containing: wheat, rye, barley, spelt
- Recommended foods: rice, maize, potatoes, soy beans, millet, potentially oats
- In ∼ 70% of cases, clinical improvement occurs within two weeks after initiating the diet.
- Histological improvement occurs within weeks to months after beginning the diet.
- In case of secondary lactase deficiency: avoid milk products
- Iron and vitamin substitution
- Supplementation of calcium and vitamin D to prevent bone loss
Managing celiac disease mainly consists of maintaining a lifelong gluten-free diet!
With infants, maintaining a gluten-free diet that only introduces small amounts of wheat (into the supplementary diet) between 17–26 weeks of age appears to have a protective effect against developing celiac disease.