Gastrointestinal and hepatology · Moderate
This case is fictional and exists for study. It describes no real patient.
32 years · female
A 32-year-old woman presents to the general practice clinic complaining of a 6-month history of persistent watery diarrhoea, abdominal bloating, and fatigue. She reports an unintended weight loss of 4 kg over this period along with occasional painful aphthous mouth ulcers. Her medical history includes Hashimoto thyroiditis, for which she takes levothyroxine. On examination, she appears pale. Her abdomen is mildly distended with diffuse tenderness on palpation, but there is no guarding or rebound tenderness. Digital rectal examination is unremarkable.
Vital signs
- HR
- 78 bpm
- BP
- 115/72 mmHg
- RR
- 14/min
- Temp
- 36.8 °C
- SpO₂
- 98%
Examination findings
- Conjunctival pallor
- Mild diffuse abdominal tenderness with bloating
- No organomegaly or abdominal masses
Investigations
| Haemoglobin | 10.2 g/dL | reference: 12.0-15.5 |
| MCV | 72 fL | reference: 80-100 |
| Ferritin | 10 ug/L | reference: 15-200 |
| Tissue transglutaminase (tTG) IgA | >120 U/mL | reference: <10 |
| Total IgA | 2.1 g/L | reference: 0.8-4.0 |
Question 1 of 3
Which of the following is the most appropriate next step to confirm the diagnosis?
In adults with suspected coeliac disease and positive IgA tTG serology, an upper gastrointestinal endoscopy with small bowel (duodenal) biopsy is required to confirm the diagnosis (showing villous atrophy, crypt hyperplasia, and intraepithelial lymphocytosis). Option B (colonoscopy) evaluates lower gastrointestinal pathology such as inflammatory bowel disease, which is less likely given the specific positive tTG serology. Option D (stool culture) rules out infectious gastroenteritis but cannot confirm coeliac disease. Option A (HLA testing) has a high negative predictive value and is useful for ruling out coeliac disease in equivocal cases, but it is not the standard confirmatory step when serology is strongly positive.
Teaching point: In adults, duodenal biopsy via upper gastrointestinal endoscopy is the gold standard for confirming a diagnosis of coeliac disease.
Question 2 of 3
Before the patient undergoes the confirmatory investigation, what crucial dietary instruction should be provided?
Patients must continue eating gluten — some gluten in more than one meal every day for at least 6 weeks (NICE NG20) — before both diagnostic serology and mucosal biopsy; coeliac disease cannot be excluded on tests performed on a reduced-gluten or gluten-free diet. Commencing a gluten-free diet prematurely (Option B) leads to mucosal healing and seronegativity, causing false-negative histopathology results. Options A and C may help with symptom management in specific secondary intolerances, but they do not replace the fundamental requirement to maintain gluten intake during diagnostic evaluation.
Teaching point: Patients must remain on a gluten-containing diet until diagnostic duodenal biopsies are complete to prevent false-negative histopathological results.
Question 3 of 3
Histopathology confirms subtotal villous atrophy consistent with coeliac disease. In addition to establishing a strict lifelong gluten-free diet, which management step is most appropriate?
Coeliac disease causes malabsorption primary affecting the duodenum and proximal jejunum, frequently leading to iron deficiency anaemia and other micronutrient deficiencies (folate, vitamin B12, vitamin D). Correcting these deficiencies with oral supplementation alongside a gluten-free diet is standard initial management. Corticosteroids (Option D) and immunosuppressants (Option C) are reserved for refractory coeliac disease unresponsive to gluten withdrawal. Colectomy (Option B) is incorrect as coeliac disease involves the small intestine, not the colon.
Teaching point: Initial management of coeliac disease involves a strict gluten-free diet alongside nutritional assessment and targeted supplementation for deficiencies like iron deficiency anaemia.
Key learning points
- Coeliac disease is an autoimmune enteropathy triggered by dietary gluten, often associated with other autoimmune conditions like Hashimoto thyroiditis.
- Adult diagnosis requires confirmatory duodenal biopsy showing villous atrophy, which must be performed while the patient is on a gluten-containing diet.
- Management requires a lifelong gluten-free diet and correction of associated malabsorptive micronutrient deficiencies (such as iron deficiency anaemia).
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