Coeliac disease is a condition in which the small intestine lining is damaged and this interferes with absorption of nutrients. Patients with coeliac disease have intolerance to a protein in gluten, which is found in wheat, rye, barley and oats. In such patients, when gluten is ingested the immune system responds by attacking the cells lining the small intestine. Specifically, tiny finger-like protrusions, called villi, are lost. These villi play a key role in the absorption of nutrients into the bloodstream. Without them, malnutrition ensues regardless of the quantity of food consumed.
Coeliac disease is also known as coeliac sprue, nontropical sprue, and gluten-sensitive enteropathy. Because the body's immune system causes the damage, coeliac disease is considered an autoimmune disorder. It is also classified as a disease of malabsorption.
The prevalence of coeliac disease in Australia may be as high as 1 in every 500 people. Patients may develop initial symptoms as children or adults. Coeliac disease is sometimes triggered or becomes active for the first time after surgery, pregnancy, childbirth, viral infection or severe emotional stress.
Coeliac disease may be asymptomatic in some patients where the small intestine is able to absorb enough nutrients to prevent symptoms. There is no typical presentation. Common gastrointestinal symptoms include chronic diarrhoea, abdominal discomfort, bloating and distension. Symptoms may or may not occur in the digestive system. For example, one patient might have diarrhoea and abdominal pain, while another patient may complain of irritability or depression. In fact, irritability is one of the most common symptoms in children. Many symptoms (eg. fatigue, anaemia, weight loss, bone pain, delayed growth and failure to thrive in infants) are secondary to malnutrition. Other possible symptoms include behavioural changes, muscle cramps, tingling numbness in the limbs, mouth ulcers, dermatitis, tooth discolouration and missed menstrual periods. Many coeliac patients are diagnosed by finding an abnormality on the blood test. This is usually iron deficiency or even anaemia.
Coeliac disease can be difficult to diagnose because symptoms are similar to those of other diseases, including irritable bowel syndrome, Crohn's disease, ulcerative colitis, diverticulosis, intestinal infections, chronic fatigue syndrome and depression. Diagnosis is suspected on the basis of the symptoms and signs enhanced by laboratory and x-ray studies. Endoscopy diagnoses the condition. Here, Gastroenterologist introduces a flexible tube carrying a tiny camera through the mouth and stomach into the small intestine. This allows a sample of intestinal tissue (a biopsy) to be obtained for examination under the microscope and checked for damage to the intestinal lining and villi. Biopsy of the small intestine is required to diagnose coeliac disease. The lining has to show atrophy or shrinking of the villi together with inflammation in the underlying mucosal tissue. The diagnosis can then be confirmed by clinical and microscopic improvement when the patient is placed on a strict gluten-free diet.
Antibodies are produced by the immune system in response to substances that the body perceives to be threatening. Coeliac disease may be strongly suggested through the presence of some abnormalities in the blood. These include elevated antigliadin antibodies, , anti-endomysial and TTG (tissue trans-glutaminase enzyme). Such blood tests are used to screen for coeliac disease especially in at risk patients for example those with family members who have coeliac disease. Positive blood tests should be followed up with an endoscopy, small bowel biopsy and histological analysis. A blood test does not definitively diagnose the presence of coeliac disease.
The standard treatment for coeliac disease is the removal of all gluten-containing foods from the diet. For many patients, this is all that is needed to control symptoms, heal existing intestinal damage (the villi regrow and regain function) and further prevent damage. Improvements can begin within days of starting the gluten free diet and the small intestine is often completely healed within 3 to 6 months in those on a strict diet.
The gluten-free diet is a lifetime requirement. Eating any gluten, no matter how small an amount, can damage the intestine. This is true for anyone with the disease, including patients without noticeable symptoms. A proportion of patients with coeliac disease do not improve on the gluten-free diet and need to receive nutritional supplements. Supplementary vitamins, minerals, especially iron, are given according to the deficiency. While mild cases of coeliac disease may not require any supplementation, severe cases require comprehensive intravenous replacement. Drug treatments are being evaluated for unresponsive coeliac disease. These patients may need to be monitored for signs of complications of the disease, which include lymphoma, osteoporosis and seizures among others.