When the Diet Is Not Enough
Refractory coeliac disease (RCD) is defined as persistent or recurrent villous atrophy with malabsorptive symptoms despite at least 12 months of strict gluten-free diet adherence, after exclusion of other causes of villous atrophy (tropical sprue, autoimmune enteropathy, common variable immunodeficiency, Crohn's disease, drug-induced enteropathy). It affects roughly 2 to 5 percent of diagnosed coeliac patients.
Type I vs Type II
RCD is subdivided based on the phenotype of intraepithelial lymphocytes. In RCD type I, IELs retain normal surface markers (CD3+, CD8+, surface TCR+) — functionally, this resembles active coeliac disease that has not responded to diet, and the prognosis is relatively favourable with immunosuppressive therapy (budesonide, azathioprine). In RCD type II, IELs are aberrant: they lose surface CD3, CD8, and surface TCR expression while retaining intracellular CD3. These aberrant IELs represent a clonal T cell population and are considered a pre-malignant condition.
The Lymphoma Risk
RCD type II carries a 40 to 60 percent risk of progression to enteropathy-associated T cell lymphoma (EATL) within 5 years — a rare but aggressive lymphoma with a 5-year survival rate below 20 percent. This makes the distinction between RCD type I and type II critically important and requires specialised flow cytometry and TCR gene rearrangement studies on duodenal biopsies.
EATL presents with weight loss, abdominal pain, diarrhoea, and small bowel obstruction or perforation. CT or PET-CT imaging and capsule endoscopy or device-assisted enteroscopy are used for staging. Treatment involves chemotherapy (CHOP-based regimens) with or without autologous stem cell transplantation, but outcomes remain poor.
Other Complications
Beyond RCD and EATL, long-standing or untreated coeliac disease is associated with several complications. Osteoporosis affects 30 to 40 percent of newly diagnosed patients due to calcium and vitamin D malabsorption. Splenic hypofunction (functional hyposplenism) occurs in up to 30 percent, increasing susceptibility to encapsulated organisms — pneumococcal vaccination is recommended. Neurological manifestations include gluten ataxia, peripheral neuropathy, and, rarely, epilepsy with occipital calcifications.
Reproductive complications include iron and folate deficiency-related anaemia, recurrent miscarriage, intrauterine growth restriction, and infertility — most of which improve on a strict GFD. Microscopic colitis co-occurs in up to 4 percent of coeliac patients and should be suspected if diarrhoea persists despite mucosal healing on biopsy.
Monitoring Strategy
All coeliac patients should have annual serology and symptom review. Those with persistent symptoms, persistent serology, or initial severe presentation warrant repeat biopsy at 12 to 24 months. RCD is rare but its consequences are severe enough to warrant vigilance — especially in older adults diagnosed after age 50, who carry the highest EATL risk.