Coeliac disease

Information and facts about Autoimmune diseases.

Coeliac disease (also called celiac disease, non-tropical sprue, c(o)eliac sprue and gluten intolerance) is an autoimmune disorder characterised by permanent damage or flattening to all or part of the villi lining the small intestine, causing scar tissue that cannot be used to absorb nutrients. This damage is caused by exposure to gluten and related proteins found in wheat, rye, malt and barley. Damage to the villi reduces the ability of the intestines to absorb nutrients, and it is believed that the resulting nutritional deficiencies likely cause the wide spectrum of symptoms associated with the disorder. Coeliac disease may lead to digestive problems, such as indigestion, heartburn and irritable bowel syndrome, unexplained weight loss or other signs of nutritional deficiency due to malabsorption, and a wide range of other problems in different bodily systems, including the nervous system, the heart, and the teeth and bones.

Other symptoms can include dermatitis (an itchy rash), excessive tiredness or fatigue, aching in joints and a general feeling of being unwell.

Coeliacs (people with coeliac disease) may also be symptom-free, but they are still doing irreversible damage to their small intestines. Regardless of the presence or absence of symptoms, the disorder is associated with an increased risk of osteoporosis and MALT lymphoma, a form of intestinal cancer. Susceptibility to coeliac disease is genetic and many cases are diagnosed in childhood, but the disease can be triggered by environmental factors at any point in life. With 1 in 250 people diagnosed, Italy has one of the highest rates of coeliac disease. It is also estimated that 1 in 250 Americans have the disease, with Italian-Americans and Irish-Americans having the highest incidence. People of African, Japanese, and Chinese descent are rarely diagnosed with the disease.

In July 2005, University of Colorado scientists published information on their studies, which indicated that exposure to gluten in the first three months of a baby's life increased the risk of coeliac disease five-fold. This is believed to be a result of gluten crossing the baby's relatively undeveloped gut barrier. However, after the baby is six months old, the risk appears to be less. There is ongoing research in this area.

The condition is frequently misdiagnosed or overlooked as it can exhibit multiple symptoms and often the patient or medical staff may not link seemingly unconnected conditions. It is most frequently misdiagnosed when the sufferer complains of diarrhea, persistent indigestion, a rash or irritable bowel syndrome.

Coeliac disease has been identified in some diabetics or people suffering from milk allergies; there is some debate in medical circles as to whether these conditions are linked to gut damage caused by the disease.

The only treatment is a life-long gluten-free diet. No medications are required, and none have proven useful; trials with immunosuppressive medicines (to control the bowel inflammation) have been largely unsuccessful. Therefore, coeliacs do not need any medication; the disease can be controlled by strict adherence to a gluten-free diet, which allows the intestines to heal and resolves all symptoms in the vast majority of cases and, depending on how soon the diet is begun, can also eliminate the heightened risk of osteoporosis and intestinal cancer.

Signs and symptoms
Strict adherence to a gluten-free diet typically resolves all symptoms and conditions caused by coeliac disease. In coeliacs who are not on a gluten-free diet, the disease may present through one or more of the following symptoms. The presence of these symptoms does not mean the individual is coeliac. These symptoms are also associated with other diseases, some of which are life-threatening; therefore, patients with these symptoms should promptly consult a doctor for differential diagnosis.

Dietary deficiencies, which may manifest as symptoms in particular body systems (e.g., digestive or nervous system) or may be noticed on routine blood tests, are common in coeliacs. Up to 50% of coeliac disease patients have malabsorption-related diarrhea (with bulky, pale, offensive-smelling stools which may float in the toilet bowl). This symptom is known as steatorrhea. However, some coeliacs suffer from constipation. Excess flatulence is common, and some coeliacs also experience infrequent, minor rectal bleeding. Unexplained weight loss, indigestion, acid reflux, excessive tiredness and an itchy rash (dermatitis) may also be a sign of the disorder.

In young children, the most common symptoms are steatorrhoea, weight loss, abdominal distension, and slow growth/failure to thrive, but irritability, vomiting and tiredness are common. It has been suggested that some cases of autism may be caused by coeliac disease.

In adults, the symptoms of coeliac disease may be mistaken for irritable bowel syndrome (IBS) or an inflammatory bowel syndrome such as Crohn's disease. However, coeliac disease is also associated with anemia, cardiomyopathy, depression, fatigue and "mental fog," dental problems (see below), adverse pregnancy outcome (particularly miscarriage), peripheral neuropathy, and according to some studies, schizophrenia. A very high proportion of patients diagnosed with dermatitis herpetiformis are coeliacs.

Selective dietary deficiencies such as dietary iron deficiency, vitamin B12 deficiency, osteoporosis (due to Vitamin D and calcium malabsorption), poor thyroid function, or other secondary dietary deficiencies may be the sole symptom (predominantly in older patients), or found in addition to diarrhea or weight loss. Some coeliacs experience dental problems as a result of malabsorption of nutrients essential for dental health. Coeliacs who have dental symptoms typically have tooth enamel problems, which manifest primarily as discoloration and/or severe tooth decay. A pattern of symmetrical decay is particularly associated with coeliac disease.

Epidemiologically, the disease predominates in Northern European populations. Estimates of its frequency among people of European origin range from 1 in 300 to 1 in 500. Some studies indicate that among the Irish, the frequency may be as high as 1 in 133. Because it is partly genetic, doctors commonly recommend that the first-degree relatives of diagnosed coeliacs should be tested for the disorder even if they are symptom-free.

There is an increased risk of intestinal T-cell lymphoma and osteoporosis in untreated cases. In recent years it has also become more evident that coeliac disease in the pregnant mother could have an adverse effect on the foetus. Offspring to mothers with undiagnosed (and untreated) coeliac disease are more often preterm and low birth weight (weigh less than 2500 grams/5 pounds at birth) than offspring to mothers without coeliac disease. This may be due to the mother's inability to absorb all the nutrients she eats. In children of women with coeliac disease and a gluten-free treatment there seems to be no such risk increase. Women with coeliac disease have fertility similar to that of the general female population, but they often have their babies at an older age

A number of patients with other diseases are often screened for coeliac disease, including patients with type 1 diabetes, Down's syndrome, Turner's syndrome, irritable bowel syndrome, lupus, and autoimmune thyroid disease.

Diagnosis

Tests
The gold standard is still upper endoscopy with biopsy of the distal duodenum or jejunum. To avoid false negative results, the first endoscopy must be done while the patient is on a normal, gluten-containing diet or very shortly after going on a gluten-free diet. Sometimes the endoscopy is repeated after the patient has been on a gluten-free diet, in order to ensure that the bowel has healed. However, upper endoscopy always carries a risk of false negative results. This is because coeliac disease may or may not damage villi throughout the entire small intestine, and upper endoscopy only examines the upper part of the intestine. In a patient whose intestinal damage is located further down, the biopsy may come back negative. If the endoscopy is positive the diagnosis is confirmed, but if it is negative, the diagnosis is not necessarily excluded.

Serology has been proposed as a screening measure, because the presence in the blood of IgA antibodies reactive against gluten and tissue transglutaminase is indicative of coeliac disease. Like the endoscopy, these tests are not accurate in patients who have been on a gluten-free diet for some time; they must be performed while the person is on a normal diet or within a relatively short time after eliminating gluten. A thorough workup includes four tests:

Anti-tissue Transglutaminase Antibody (tTG), IgA. This test is sometimes used alone. If this test is positive it is highly likely that the patient has celiac disease.
Anti-Gliadin Antibodies (AGA), IgG and IgA. These tests are often useful when testing young symptomatic children, but they are found in fewer coeliacs than Anti-tTG, and their presence does not automatically indicate coeliac disease because they are found in some other disorders. Some people have an IgA deficiency that causes a false negative test; due to this and other factors, the IgA test has a relatively high rate of false negatives.
Anti-Endomysial Antibodies (EMA), IgA. This test is being replaced by the Anti-tTG test because both tests measure the autoantibodies that cause the tissue damage associated with coeliac disease. Many physicians still order this test.
Anti-Reticulin Antibodies (ARA), IgA. Anti-ARA is not ordered as frequently as it once was, because it is less sensitive and less specific than the other tests. It is found in about 60% of people with coeliac disease and 25% of those with dermatitis herpetiformis.
Many doctors will not consider positive blood tests as definitive proof of coeliac disease, but will still require biopsy confirmation. A growing minority consider coeliac disease to be diagnosed where the patient has positive blood tests and shows improved symptoms after the adoption of a gluten-free diet. Because upper endoscopies are uncomfortable, expensive, and may produce false negative results, this group of doctors considers serology tests and a positive response to eliminating gluten from the diet to be sufficient for diagnosis. A small minority of doctors advocate gluten-free diets even for symptom-free patients who have not had an endoscopy but have had a positive blood test, because some confirmed coeliacs are completely symptom-free throughout their lives; in symptom-free patients, the purpose of the diet is to avoid nutritional deficiencies, osteoporosis, and intestinal lymphoma.

Other tests that may assist in the diagnosis are a full blood count, electrolytes, renal function and liver enzymes. Coagulation testing may be useful to identify deficiency of vitamin K, which predisposes patients to hemorrhage.

Biopsy appearance
The standard changes seen under dissecting microscope are loss of villous height and hypertrophy of the crypts. There is often some degree of inflammation with inflammatory cells (plasma cells and lymphocytes) seen in the lamina propria.

Causes
The cause is presently presumed to be:

Partly a genetic susceptibility to the illness (identical twins do not have 100% concordance however).
Together with an environmental agent, probably a virus or other infection, but stress and pregnancy have also been invoked as possible triggers.
It is associated with other autoimmune diseases; these diseases are also probably a combination of susceptibility and infection.
Possible exposure to gluten as a young baby before the gut barrier has developed fully (although this is still subject to further research).
Autoantigens are probably of major importance in the pathogenesis of coeliac disease (transglutaminase), a trait it shares with many other autoimmune diseases; thyroiditis: thyroglobulin, thyroid peroxidase; multiple sclerosis: myelic basic protein, etc.). To some extent infectious agents may increase the risk of certain autoimmune diseases (e.g. Coxsackie B in type 1 diabetes). However, in the case of coeliac disease, there are few proofs of infections triggering coeliac disease. Some researchers have suggested that smoking is protective against coeliac disease. Results on this topic are however inconsistent, and smoking cannot be recommended as a means to avoid developing coeliac disease.

Pathophysiology
Antibodies to the enzyme tissue transglutaminase (tTG) are found in an overwhelming majority of cases, and cross-react to gluten1. This has led to the theory that they cause the autoimmune attack on the bowel lining (which is high in tTG), prompted by the continuous stimulation by gluten. This reaction happens almost exclusively in patients with human leukocyte antigen types DQ2 and DQ8, which is inherited in families. The exact cause for this predisposition is still uncertain, but up to 95% of patients carry these genes (although they are also common in the general population in Western countries).

The inflammatory process leads to disruption of the structure and function of the small bowel's mucosa, and causes malabsorption (it impairs the body's ability to absorb nutrients and fat-soluble vitamins A, D, E and K from food).

The targets of the immunologic response are gliadin, hordein, and secalin, proteins contained in the gluten component of wheat, barley, and rye respectively. Traditionally, oats have been included in the list as well, but some recent studies have brought into question whether this is necessary. Maize (corn), sorghum, and rice are considered safe for a patient to consume. They contain types of gluten that do not trigger the disease.

Treatment
In the vast majority of patients, a strict gluten-free diet will relieve the symptoms. A tiny minority of patients suffer from refractory sprue, which means they do not improve on a gluten-free diet. This may be because the disease has been present for so long that the intestines are no longer able to heal. In other patients, the intestinal damage of coeliac disease may have been aggravated by other problems, such as intolerance to the dietary proteins found in eggs, milk, or soy. Just as a person who is allergic to cats may also happen to be allergic to pollen, a patient with coeliac disease may also happen to have other food intolerances that cause similar symptoms. In rare cases only the complete removal of members of the Gramineae family of plants from the diet will bring about recovery from symptoms.

Epidemiology
It is estimated that 1 in every 133 to 500 persons (up to 3 million) in the United States and Europe are affected by coeliac disease. The disease is not limited to those of European origin; it is found in other races, but the prevalence is not known. Coeliac disease is more common in women than in men. In symptomatic adults, the average delay between onset of symptoms and diagnosis is estimated at 11 years. This lengthy delay appears to be caused by the variety of symptoms associated with the disease, the fact that some coeliacs have no digestive-tract symptoms at all, and lack of widespread, up-to-date information among doctors.

Social impact

Lifelong diet
The lifelong diet can be difficult and socially troublesome, especially in young patients, but it is crucial in order to avoid serious health consequences. Teenagers in particular occasionally rebel against the dietary strictures and suffer relapses or complications as a result. The widespread use of wheat byproducts in prepared food, soups and sauces can make dining out problematic. This is especially true in the United States, where celiac disease is less widely-known among the wider population than it is in Europe. However, certain types of restaurant (e.g., Japanese, Thai, Indian, and Latin American) already offer a wide range of gluten-free menu options, and many major restaurant chains have responded to growing awareness of celiac disease by posting information about the gluten content of their menu items on their websites.

It is important for coeliacs to understand that one does not "get over" coeliac disease; it is present for life. As coeliac disease has become better understood, the availability of gluten-free replacements for everyday treats such as muffins, bagels, pasta and the like has continually improved, as has their quality. This positive trend shows no sign of slowing, so it will become easier and easier to manage a gluten-free diet.

Coeliacs and the Eucharist
The Christian sacrament of the Eucharist presents a unique challenge for Christian sufferers of coeliac disease. In its classical form, the bread and/or communion wafers have traditionally contained wheat flour, and therefore gluten. Coeliacs are therefore presented with a choice between denying themselves a central part of their religious practice or placing themselves at risk of serious illness. In response to this, some makers of communion wafers have begun making gluten-free versions (usually made of rice), which are now widely available. Many churches permit (or have no official policy on) use of these wafers, while other churches do not allow them.

In particular, Roman Catholic doctrine requires that the Eucharistic host (communion wafer) must contain at least some unleavened wheat, as did the bread served at the Last Supper. The Catholic Church has approved the use of low-gluten wafers, but even these are not gluten-free. Some Catholic coeliac sufferers have requested permission to use rice wafers; these petitions have so far been denied 2.

Official Roman Catholic doctrine is that a Catholic may validly receive communion by consuming either the consecrated host or the consecrated wine (or both). Because Christ is risen, his Body and Blood are reunited; therefore each sip of consecrated wine is both the Body & Blood, as much as each host is also both the Body & Blood. In both cases, the accidents of bread and wine remain (see Transubstantiation). The Council of Trent decreed that all of Christ, his Body, Blood, Soul, & Divinity are fully present in each species:

For we do not receive in the Sacred Host one part of Christ and in the Chalice the other, as though our reception of the totality depended upon our partaking of both forms; on the contrary, under the appearance of bread alone, as well as under the appearance of wine alone, we receive Christ whole and entire (cf. Council of Trent, Sess. XIII, can. iii).
Therefore, since any Catholic can receive the Eucharist in the "fullness of the sacrament" (Catechism, Section 1390) simply in a sip of consecrated wine (even an approved low-alcohol wine), even those who cannot safely consume wheat (or indeed, any other grain) can safely partake of the Eucharist.

The Orthodox Church also requires that the bread used at the Eucharist be made with wheat flour; here the bread is leavened with yeast. In the Orthodox practice, the consecrated bread and wine are given together from a chalice with a spoon. Some Orthodox coeliac sufferers have been able to receive communion simply by having the priest take only wine in the spoon; others, more sensitive to wheat, have had to have some of the wine set aside before the bread is added to the chalice. This latter case is extremely unusual, and is strictly speaking only permissible with the blessing of the diocesan bishop. While the Orthodox do not have such an explicit rationale as the Roman Catholic Church, their general understanding is that, in the case of exceptions made for the sake of Economy, the Holy Spirit makes up whatever is lacking.

Coeliacs and Passover
The Jewish festival of Pesach (Passover) also presents problems with its obligation to eat matzo. Matzo is normally made from wheat or other gluten-containing grains. People with coeliac disease are sometimes told they can rely on matzo baked either from spelt or from strains of oats bred for lack of gluten, however neither are suitable for people following a gluten-free diet. The festival can be very limiting, as matzo meal (fine-ground matzo) is used as a replacement for flour in many products to avoid other stringencies of the festival.

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