Gastroenterology and hepatology for MRCPI Part 1

A 32-year-old woman presents with 4 months of intermittent diarrhoea, bloating and fatigue. Haemoglobin 104 g/L with a low ferritin. Anti-tissue transglutaminase IgA is strongly positive and total IgA is normal. She has already started a gluten-free diet on her own two weeks ago and feels better. What is the most appropriate next step?

1. Start iron replacement and take no further action Incomplete. Iron deficiency needs correcting, but leaving the underlying diagnosis unconfirmed misses the associated risks and the need for follow-up.
2. Advise her to resume a gluten-containing diet and arrange duodenal biopsy correct Correct. Serology alone does not establish the diagnosis in adults, and the histology normalises on a gluten-free diet. She needs an adequate gluten challenge before endoscopy, or she risks a lifelong restrictive diet on an unconfirmed diagnosis.
3. Refer directly for capsule endoscopy Wrong test. Capsule endoscopy has a role in complicated or refractory coeliac disease, not in initial diagnosis, and it does not obtain the tissue needed.
4. Repeat the antibody test in 6 months on the gluten-free diet Wrong. Antibody titres fall on a gluten-free diet, so the repeat test will be uninterpretable for diagnosis. Falling titres are used to monitor adherence, not to diagnose.
5. Confirm coeliac disease on serology alone and continue the gluten-free diet Wrong in adults. A no-biopsy pathway exists in selected children with very high titres, but adult practice still requires histological confirmation.

The point: Coeliac diagnosis in adults needs serology AND biopsy while eating gluten. Always check total IgA, because IgA deficiency produces false-negative tTG. Once confirmed, address bone density, functional hyposplenism and vaccination, and screen first-degree relatives.

Source: NICE NG20 — Coeliac disease: recognition, assessment and management NICE · tier 1, national regulator or guidance