A recent paper reviewing the clinical practice guidelines for the management of coeliac disease stated the importance of having dietetic input into the development of guidelines, considering that primary management is through the diet.¹ The review also emphasised the importance of patient involvement to help improve the implementation, patient adherence and disease outcome. The Coeliac Society of Ireland welcomed the opportunity to have an input into the recently published ICGP quick reference guide on ‘Diagnosis and management of coeliac disease’.²

It is hoped that the involvement of dietitians in these updated guidelines will improve the diagnosis and consistency in management of coeliac disease in adults by both the GP community and the dietetic community. This article headlines some of the key areas in the latest reference guide 

Who should be tested for suspected coeliac disease?

The guideline outlines 50 clinical presentations of coeliac disease (see Table 1).

 (click to enlarge)

While not all these presentations would necessarily need serological testing, GPs, dietitians, nurses and health professionals should ensure the following people are tested for coeliac disease:

• Patients with symptoms, signs or laboratory evidence suggestive of malabsorption such as chronic diarrhoea or steatorrhea
• Patients with a first-degree relative with coeliac disease should be tested if they have signs or symptoms consistent with the disease and testing should be considered in those who are asymptomatic
• Patients with type 1 diabetes should be tested at diagnosis and periodically thereafter.

They should also actively case-find through offering serological testing to people with any of the following presentations:

• Persistent unexplained abdominal or gastrointestinal symptoms
• Faltering growth
• Unexplained iron, vitamin B12 or folate deficiency
• Autoimmune thyroid disease at diagnosis
• Irritable bowel syndrome 

In addition, serological testing should be considered for coeliac disease in people with any of the following:

• Metabolic bone disorder (reduced bone mineral density or osteomalacia)
• Unexplained neurological symptoms (particularly peripheral neuropathy or ataxia)
• Unexplained subfertility or recurrent miscarriage
• Persistently raised liver enzymes with unknown cause
• Dental enamel defects
• Down’s syndrome
• Turner syndrome.

What tests to use for the diagnosis of coeliac disease? 

Historically there has been confusion over the types of serological investigations for diagnosis of coeliac disease as well as the referral path for biopsy. The new guidelines make this easier with diagnostic algorithms as shown in Figures 1 and 2.

 (click to enlarge)

 (click to enlarge)

There is a paucity of literature on the amount of gluten and length of time a patient should be on a gluten-containing diet prior to diagnosis. The current consensus is that the patient must be eating gluten in more than one meal daily for more than six weeks prior to testing. As we all know, many patients go gluten free themselves due to identifying an issue with wheat foods. 

The new guidelines recommend that these patients would need to go undergo a 14-day gluten challenge of ≥3g of gluten/day (two slices of wheat bread per day). This is thought to be enough to induce histological and serological changes in most adults with coeliac disease. However, the challenge can be prolonged to eight weeks if serology remains negative at two weeks. This may be very difficult for many patients who have suffered with severe symptoms and as such would be very reluctant to reintroduce gluten even if only for two weeks. In this situation the new guidelines recommend that genetic testing (HLA-DQ2/DQ8) should be considered. 

While positive HLA typing does not confirm a diagnosis, a negative result assures a 99% probability a person will NOT develop coeliac disease. While a positive HLA typing does not mean a patient will develop coeliac disease it may encourage the patient to do a gluten challenge prior to serological testing or biopsy for proper diagnosis. Finally, positive serological testing should be followed up with a duodenal biopsy.

Management 

The guidelines specify the importance of referral to a CORU registered dietitian with the recommended referral pathways outlined in Table 2. 

Table 3 outlines the blood tests that should be requested at diagnosis.

Multiple studies report evidence of reduced bone mineral density in up to 75% of patients at diagnosis; as such, patients should be assessed for their risk of osteoporosis (see Table 4). In patients not at high risk of osteoporosis, measure BMD not later than age 30-35 years and repeat every five years. Repeat every 2-3 years in cases of low BMD or where there is evidence of ongoing villous atrophy or poor dietary adherence.

Patients should be reviewed annually with their doctor or with a dietitian who can access advice from the doctor if required. This review can take place in the primary or secondary care setting and assess for body mass index (BMI), symptomatology, compliance with diet and complications of their disease. Patients should be reviewed more frequently at other times such as pregnancy or times of high emotional stress. Coeliac serology (IgA tTG or IgA DGP antibodies) should be repeated along with similar bloods as outlined in Table 3. 

 (click to enlarge)

GPs should provide patients with information and encourage them to join the Coeliac Society of Ireland (www.coeliac.ie).

The guidelines suggest that pure gluten-free oats may be included from initial diagnosis as only 5% of people react to the avenin in pure gluten-free oats. However, if symptoms do not settle or blood results do not improve on an otherwise strict gluten-free diet, a trial period excluding gluten-free oats from the diet may be considered.

If symptoms persist despite a gluten-free diet, other conditions should be considered by the GP:

• Lactose intolerance
• Pancreatic insufficiency
• Wheat/malt intolerance
• Lymphoma
• Microscopic colitis
• Small intestinal bacterial overgrowth (SIBO)
• Irritable bowel syndrome (IBS)
• Refractory coeliac disease.

If symptoms persist after six months on a gluten-free diet, GPs should refer to a dietitian to assess dietary compliance and consideration of other diet-related issues such as IBS, SIBO, lactose/wheat/malt intolerance. If the patient is compliant, but the following symptoms persist, the GP should consider referral to a gastroenterologist for repeat endoscopy or further investigation:

• Poor response to gluten-free diet
• Weight loss on a gluten-free diet
• Blood in stools
• Onset of unexplained abdominal pain
• Abnormalities in blood results, including persistent positive coeliac serology.

Non-coeliac gluten sensitivity 

Non-coeliac gluten sensitivity is a syndrome characterised by intestinal and extra-intestinal symptoms related to the ingestion of gluten-containing food, in patients who are not affected by either coeliac disease or wheat allergy. It is essential to rule out coeliac disease in these patients. This is largely a diagnosis of exclusion. 

Patients should be referred to a dietitian. After adherence to a gluten free diet with resolution of symptoms a gluten challenge may be performed to make a definitive diagnosis. The etiology of this condition is currently unknown and further study is needed to elucidate any long-term complications that may result. 

References

1. Theodoridis X, Grammatikopoulou MG, Petalidou A, Patelida M, et al. Dietary management of celiac disease: Revisiting the guidelines. Nutrition 2019; 66:70-77
2. Burska, S.; Russell, A.; Flanagan, Richelle; ICGP Quality in Practice Committee Diagnosis and Management of Adult Coeliac Disease: Quick Reference Guide 2020 https://www.icgp.ie/go/library/catalogue/item/29696FE3-9EC8-49AC-861194B26CBFE410