Coeliac disease: hot topic

Coeliac disease is an enteropathy of the small intestine, for which there is an associated genetic susceptibility.¹

In those who have the disease, an immunological response is triggered by dietary gluten.

The prevalence may be up to 1% in the UK, although NICE suggests that only 10-15% of those patients will have a formal diagnosis of coeliac disease.²

According to the latest NICE guidance, presenting symptoms of coeliac disease may include diarrhoea, steatorrhoea, subsequent malabsorption and weight loss or failure to thrive.¹

Moreover, coeliac disease may also present with lethargy, anaemia, symptoms that are suggestive of irritable bowel syndrome, liver disease, osteoporosis and neuropathy.¹

Coeliac disease may be asymptomatic. Asymptomatic patients with coeliac disease may be found through screening those who are at increased risk of developing the disease, for example, where a first-degree relative is affected.¹

Diagnosis

Serological testing for coeliac disease involves measurement of IgA tissue transglutaminase first line. If this is equivocal, IgA endomysial antibody testing is performed.

If these results are positive, a gastroenterology referral is indicated, with a view to performing a duodenal biopsy.² Duodenal biopsy is the mainstay of diagnosis in coeliac disease.

Serological testing in infants needs to be performed when gluten has been introduced in their diet.²

It is important to make patients aware that serological testing does not diagnose coeliac disease in itself and further investigations may be required.

Patients should also be advised that a gluten-free diet should only be introduced after a positive duodenal biopsy result.

Human leukocyte antigen status may sometimes be helpful in confirming the diagnosis, for example, in those who have self-treated with a gluten-free diet and have not undergone prior testing.¹

NICE recommends offering serological testing to those with:

• Chronic or intermittent diarrhoea
• Lethargy
• Failure to thrive (children)
• Persistent or unexplained GI symptoms
• Abdominal pain with cramping or distension
• Unexplained iron deficiency anaemia²

It should also be offered to those with autoimmune thyroid disease or type 1 diabetes. Testing may be considered for patients with:

• Addison’s disease
• Autoimmune liver conditions
• Low-trauma fracture
• Lymphoma
• Persistently raised liver enzymes with unknown cause
• Sarcoidosis
• Unexplained subfertility²

Management

Once a gluten-free diet has been initiated with advice from the dietitian, annual follow-up may be commenced.

Subsequent dietary adherence may be assessed by asking patients about symptom control, dietetic review, serum antibodies and/or follow-up biopsy.

According to the NICE guidance, the need for long-term follow-up is controversial.1 Management of coeliac disease involves a lifelong gluten-free diet to relieve symptoms and avoid complications, and there is a view that follow-up is likely to encourage this.²

Poor dietary adherence may be related to age of diagnosis, understanding of the condition and psychological factors.¹

In newly diagnosed patients, support groups may be a helpful source of information and may encourage adherence to a gluten-free diet.

Patients in the UK should be advised about gluten-free items available on prescription. It is recommended that when assessing adherence to a gluten-free diet, it should be confirmed that at least the recommended minimum monthly amounts of gluten-free products are being prescribed.¹

Annual blood tests should be performed to assess absorption in the small intestine, incuding:

• FBC
• Ferritin
• Folate
• Vitamin B12
• Bone profile and vitamin D level
• LFTs, including alkaline phosphatase and aspartate aminotransferase/alanine aminotransferase
• TFTs and serum glucose may be helpful in testing for associated autoimmune conditions^1,2

Tests for dietary adherence, such as anti-tissue transglutaminase or endomysial antibodies, should be performed with the dietary review.¹

Complications

The risk of osteoporosis and bone fracture is increased in patients with coeliac disease, although it decreases following the initiation of a gluten-free diet.

Bone mineral density seems to increase in the first year of maintaining a gluten-free diet.¹

This should be measured one year after initiation of a gluten-free diet in patients with additional risk factors for osteoporosis, or those aged over 55 years.¹

Coeliac disease may cause hyposplenism, which may result in impaired immunity to encapsulated bacteria, so pneumococcal vaccination is recommended.

Dermatitis herpetiformis may be caused by exposure to gluten, and is the cutaneous manifestation of coeliac disease.¹

Undiagnosed or untreated coeliac disease may also result in GI symptoms, as well as longer-term complications such as osteoporosis, and an increased risk of intestinal malignancy, growth failure and delayed puberty in children.^1,2

• Dr Kochhar is a GP in Bexhill, East Sussex

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References

1. NICE. Coeliac disease: recognition, assessment and management. NG20. London, NICE, September 2015
2. Ludvigsson JF, Bai JC, Biagi F et al. Diagnosis and management of adult coeliac disease: guidelines from the British Society of Gastroenterology. Gut 2014; 63: 1210-28

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