Coeliac disease in type 1 diabetes with IgA deficiency — SCE Endocrinology MCQ

Correct answer: E — IgG-based coeliac serology followed by gastroenterology assessment

The best answer is “IgG-based coeliac serology followed by gastroenterology assessment”. IgA deficiency can make IgA-based tests falsely negative; NICE recommends IgG EMA, IgG deamidated gliadin peptide or IgG tTG testing when IgA is deficient. “Exclude coeliac disease because tissue transglutaminase IgA is negative” is less appropriate because the assay is unreliable when its immunoglobulin substrate is absent “Start pancreatic enzymes without investigating malabsorption” is less appropriate because pancreatic insufficiency needs supporting evidence and does not address the serological limitation “Diagnose diabetic autonomic diarrhoea before excluding coeliac disease” is less appropriate because autonomic diarrhoea is a diagnosis made after relevant alternative causes are assessed “Prescribe long-term antibiotics for presumed bacterial overgrowth” is less appropriate because empirical prolonged antibiotics neither diagnose coeliac disease nor correct the false-negative test mechanism

Reference: NICE NG20: Coeliac disease — recognition, assessment and management. https://www.nice.org.uk/guidance/ng20/chapter/Recommendations