Coeliac disease — branching viva

Station opening

Examiner: "Define coeliac disease and outline your approach to a child referred with possible coeliac disease." [1]

Strong candidate (must-hit)

• Defines coeliac disease as a permanent, immune-mediated small-bowel enteropathy induced by dietary gluten in people who carry HLA-DQ2 or HLA-DQ8; frames the approach around recognising the classic and non-classic faces, confirming the diagnosis with immunoglobulin A anti-tissue-transglutaminase plus a total immunoglobulin A taken while the child is still eating gluten, applying the ESPGHAN 2020 no-biopsy pathway when the criteria are met, and treating with a strict lifelong gluten-free diet with monitoring; states that the gluten-on-board rule is the single most important practical principle. [1]

Weak candidate

• "Coeliac disease is an allergy to wheat, and I would test for it and start a gluten-free diet." [1]

Branch A — The classic toddler

Examiner: "An eighteen-month-old has loose pale bulky stools, a distended abdomen, irritability and failure to thrive after starting gluten. What is the diagnosis and how do you confirm it?" [2]

Strong

• Makes the diagnosis of classic coeliac disease from the steatorrhoeic stools, the distended abdomen with wasted buttocks, the irritability and the fall across the weight centiles after weaning onto gluten; confirms it with immunoglobulin A anti-tissue-transglutaminase plus a total immunoglobulin A on a gluten-containing diet, applying the no-biopsy pathway when the titre is at or above ten times the upper limit of normal with positive endomysial antibody on a separate sample, and otherwise duodenal biopsy with bulb biopsies showing villous atrophy, crypt hyperplasia and raised intraepithelial lymphocytes. [2] [1]

Weak

• "I would stop gluten and see if he improves, then test the antibodies." [1]

Branch B — The fourteen-year-old with refractory iron deficiency

Examiner: "A fourteen-year-old has iron-deficiency anaemia that has not responded to three months of oral iron, short stature and a maternal aunt with coeliac disease. She is still on a gluten diet. Her anti-tissue-transglutaminase titre is twelve times the upper limit of normal. What is your next step, and can you make the diagnosis without a biopsy?" [1]

Strong

• Sends a separate serum sample for endomysial antibody and confirms a normal total immunoglobulin A, then applies the ESPGHAN 2020 no-biopsy pathway: a symptomatic child with an anti-tissue-transglutaminase titre at or above ten times the upper limit of normal, positive endomysial antibody on a separate sample and normal total immunoglobulin A can be diagnosed with coeliac disease without duodenal biopsy, the human leukocyte antigen requirement having been dropped in 2020; explains that iron refractory to oral iron is a classic clue because iron is absorbed at the duodenal tip where the atrophy is worst. [1] [4]

Weak

• "The titre is high, so I would refer for a biopsy to be sure before doing anything else." [1]

Branch C — The eight-year-old with type 1 diabetes

Examiner: "An eight-year-old with type 1 diabetes has a positive anti-tissue-transglutaminase on routine screening but no gut symptoms. The total immunoglobulin A is normal. Do you treat, and why?" [5]

Strong

• Confirms the diagnosis, classically with a positive endomysial antibody on a separate sample and, where the no-biopsy criteria are not fully met, with duodenal biopsy; treats even though the child is asymptomatic, because untreated coeliac disease can impair growth, reduce bone density and destabilise glycaemic control; manages the gluten-free diet jointly with a dietitian who reconciles it with carbohydrate counting and insulin adjustment; and explains that the three to eight per cent prevalence of coeliac disease in type 1 diabetes is the reason for periodic screening. [5] [1]

Weak

• "She has no symptoms, so I would just watch her and retest in a few years." [5]

Branch D — The child already on a gluten-free diet

Examiner: "A family has read online that gluten is harmful and has put their six-year-old on a gluten-free diet for two months. The symptoms have improved and the coeliac serology is now negative. How do you establish whether she actually has coeliac disease?" [1]

Strong

• Explains that the negative serology is uninterpretable because the antibodies fall within weeks on a gluten-free diet; establishes the diagnosis by a formal gluten challenge, reintroducing a gluten-containing diet for several weeks and repeating the serology and, where needed, the duodenal biopsy; counsels the family that the challenge is symptom-laden and unpleasant, and that the lesson is to test before the diet is ever started. [1] [3]

Weak

• "The negative antibodies mean she does not have coeliac disease, so she can stay on the diet." [1]

Close

Examiner: "Summarise your approach to the child with suspected coeliac disease in one sentence." [1]

Strong

• "Coeliac disease is a permanent gluten-induced immune enteropathy in HLA-DQ2 or DQ8 carriers: I suspect it in any child with faltering growth, refractory iron deficiency, short stature, chronic diarrhoea or a distended abdomen, confirm it with immunoglobulin A anti-tissue-transglutaminase plus total immunoglobulin A on a gluten-containing diet, apply the ESPGHAN 2020 no-biopsy pathway when the titre is at or above ten times the upper limit of normal with positive endomysial antibody on a separate sample, and treat with a strict lifelong gluten-free diet with monitoring." [1] [5]