Refractory sprue (RS) is a complex autoimmune disorder much like the more common celiac sprue but, unlike celiac sprue, it is resistant or unresponsive to six months of treatment with a strict gluten-free diet. Gliadin, a component of the wheat storage protein gluten, together with similar proteins in barley and rye, are the villains that trigger the immune reaction in celiac sprue. The diagnosis of RS is made by exclusion, especially of any other disorder that can affect the huge number of thread-like projections that line the interior of the intestine (intestinal villi), such as intestinal lymphoma, Crohn's disease, small intestinal bacterial overgrowth or hypogammaglobulinemia.
The intestinal villi are the means by which the gut absorbs fluids and nutrients. In celiac sprue and refractory sprue, these villi shrink and shrivel (atrophy) affecting the absorption of nutrients via the intestines. In celiac sprue, treatment by means of a strict gluten-free diet is usually sufficient to overcome the disorder. However, refractory sprue is just that: refractory or stubbornly resistant to treatment. Only a small percentage of the people with celiac sprue will develop RS, and these patients are almost invariably 30 years of age or older. However, as yet, it is impossible to predict which patient of those with celiac sprue will develop RS.