What is celiac disease?
Celiac disease is a disease that affects the whole body, especially the gastrointestinal tract and especially the first sections of the small intestine. The disease is of autoimmune origin, appearing in genetically predisposed patients.
It is relatively common and affects about 1-2% of the population. In many cases the diagnosis is made by pediatric specialists, but it is not uncommon that at early ages it may go unnoticed and patients are diagnosed at older ages, even 25% are over 60 years of age.
What is the cause?
Celiac disease is triggered by the consumption of gluten, which is a protein component contained in the flour of certain cereals, mainly wheat, rye, barley and, to a lesser extent, oats. When gluten is consumed, celiac disease patients develop characteristic lesions of varying intensity, preferably intestinal.
What symptoms does it produce?
The symptoms are very varied, the most frequent are digestive, from hardly any abdominal discomfort, even in asymptomatic patients, to a wide range of symptoms. The usual digestive complaints are stomach pain or diffuse abdominal pain, slow and heavy digestion, bloating, altered bowel habits with a predominance of diarrhea or sometimes even constipation.
Frequently, certain extra-digestive alterations are associated such as hematological disorders, the most important being iron deficiency (with or without anemia), alteration of liver tests, musculoskeletal alterations, such as the development of osteoporosis, growth retardation in children, thyroid diseases, fertility-related disorders, recurrent mouth ulcers, dermatological processes such as dermatitis herpetiformis, neurological disorders, depression and anxiety, etc.
How is it diagnosed?
In general the diagnosis is based on clinical suspicion and therefore the performance of a specific serology (determination of antibodies in blood), genetic markers and the study of intestinal biopsies. None of these tests alone is sufficient to confirm the diagnosis and at present, depending on each case, different diagnostic algorithms are established to select the type of tests to be performed to obtain a diagnosis of certainty.
What are the most frequent explorations for diagnosis?
The following are the main diagnostic tests to be performed in these patients.
- Serological studies: Several serological markers are currently available:
- Anti-Gliadin antibodies: directed against gliadins (gluten fragments). They are not very specific and false positives are frequent.
- Anti-Endomysial antibodies: They are very specific, but somewhat less sensitive.
- Anti-tissue transglutaminase antibodies: more sensitive, but less specific. The most informative are of the IgA class. Its positivity has a linear relationship with the presence and severity of villous atrophy in the duodenal mucosa.
- Anti-deamidated Gliadin peptide antibodies: More sensitive than anti-endomysial antibodies, presenting a similar specificity to anti-transglutaminase antibodies. The most commonly used are those of the IgG class and are determined especially in children under 18 months of age and in patients with IgA deficiency.
Serological tests in adults are much less sensitive than in children, and their results are frequently negative, especially for anti-transglutaminase Ac, so other detection systems are being studied, to be used in the near future.
- Genetic studies: The HLA system (human lymphocyte antigens, located on the short arm of chromosome 6) is implicated in the onset of the disease. This system is responsible for monitoring the body’s own cells and its presence is related to the appearance of various autoimmune diseases. There are a number of variations in the HLA system that predispose to the disease. Thus, HLA-DQ2 is present in 90% of celiac patients and about 5% have HLA DQ8.
The presence of these histocompatibility antigens does not imply that having them positive means developing the disease (in fact, celiacs are only 2-5% of HLA-DQ2 carriers).
- Duodenal biopsies: These are obtained by performing a gastroscopy to reach the duodenum and take biopsies, using a forceps introduced through the endoscope. In celiac disease, duodenal biopsies show lesions of varying intensity that are classified according to histological criteria (the most commonly used are the Marsh criteria), ranging from intraepithelial CD3 lymphocyte infiltrates to the appearance of atrophied intestinal villi.
- Familial study. As celiac disease has a genetic basis, once a patient has been diagnosed with celiac disease, the existence of the disease in close relatives, mainly first-degree relatives, should be investigated.
- Differential diagnosis: It should be borne in mind that some cases of celiac disease may have certain peculiarities that may require more complex procedures, such as celiac disease refractory to gluten-free diet, collagen sprue, etc.
It should also be taken into account that other diseases may have similar findings, preferably histologically, such as inflammatory bowel diseases, side effects of certain drugs such as NSAIDs, certain infections such as Helicobacter Pylori or Giardia Lamblia, food allergies, intestinal lymphoma, etc. Therefore, a diagnosis of certainty, with the appropriate complementary examinations, should be made in all cases.
It is also advisable to rule out other processes that can produce very similar symptoms, such as various food intolerances, preferably intolerance to disaccharides (lactose, fructose and others), gluten intolerance without celiac disease, as well as disorders related to the intestinal biota (intestinal bacteria) such as syndromes with bacterial overgrowth. All these disorders have their own diagnostic techniques.
How is celiac disease treated?
Although a multitude of clinical trials are underway with new diagnostic and therapeutic strategies and the appearance of new drugs that will considerably change the future treatment of celiac disease, in practice the only existing treatment at present consists of maintaining a strict gluten-free diet for life. The diet does not cure the disease, but it controls it and normally achieves clinical normalization, as well as avoiding possible complications.
It has been shown that continuous consumption of small amounts of gluten can severely damage the intestinal villi or cause other major undesirable alterations and/or disorders, even in the absence of symptoms.
What does the gluten-free diet consist of?
The gluten-free diet is fundamentally based on the consumption of natural and fresh foods that do not contain this protein component, such as milk and dairy products; meats and sausages; fish and seafood; eggs in their various forms of consumption; all kinds of fruits, vegetables, legumes and cereals that do not contain gluten such as corn, rice, millet and sorghum, combining them together in a varied and balanced way.
Any product containing wheat, barley, rye, triticale (hybrid of wheat and rye) or oats as an ingredient should be eliminated from the diet. As a general rule, bulk products, handmade products, or those that are not labeled, where the list of ingredients cannot be checked, should be eliminated from the diet.
A very important aspect for the patient refers to the precaution in food handling in order to avoid food contamination. Avoid frying gluten-free foods in oils where gluten-containing products have been previously prepared. In those households where there is a coeliac, it is recommended to eliminate wheat flours and breadcrumbs and use instead gluten-free flours and breadcrumbs or flakes of mashed potato for batter, breading or thickening sauces. In this way, almost all foods that are prepared can be eaten by the entire family of the celiac patient.
At present, celiac disease patients should be followed up in all cases and analytical tests or other complementary explorations should be carried out periodically to check the good evolution of the disease and avoid complications.