Villous atrophy, crypt hyperplasia and intraepithelial lymphocytosis
Expansion
The triad
- Villous atrophy, reducing absorptive surface area
- Crypt hyperplasia, as the epithelium attempts to compensate
- Intraepithelial lymphocytosis, over 25 lymphocytes per 100 enterocytes
Marsh classification
- Marsh 0 - normal
- Marsh 1 - intraepithelial lymphocytosis alone
- Marsh 2 - plus crypt hyperplasia
- Marsh 3 - plus villous atrophy, graded a (partial), b (subtotal), c (total)
“Lymphocytes first, then crypts, then villi.” The lesion develops from the surface downwards.
The changes are patchy, so at least four biopsies from the second part of the duodenum and one or two from the bulb are required; sampling error is a common cause of a missed diagnosis.
The patient must be eating gluten, in more than one meal daily for at least 6 weeks, or the histology normalises and the diagnosis is missed.
Villous atrophy is not specific to coeliac disease: it also occurs in tropical sprue, giardiasis, common variable immunodeficiency, cows’ milk protein intolerance, and with olmesartan, NSAIDs and chemotherapy.
Complications: iron and folate deficiency, osteoporosis, hyposplenism, enteropathy associated T cell lymphoma and small bowel adenocarcinoma.