July 8th, 2012
Gluten: How often is it the culprit?
All gastroenterologists are very familiar with celiac disease, including its characteristic findings on small bowel biopsy and the treatment with a gluten-free diet. But I have noticed that we as gastroenterologists approach the possibility of sprue, or those suspected of having gluten sensitivity without sprue, with extraordinary variability. For instance, a negative screening tissue transglutaminase (TTG) has greater than a 99% negative predictive value (essentially excluding celiac disease), but a positive TTG has only a 25% to 35% positive predictive value, meaning that most patients who test positive do not have celiac disease.
So, first, here are some questions:
1) Do you still take biopsies in some patients with a negative TTG, and, if so, how do you decide which patients should undergo biopsy?
2) Do you take biopsies in all patients with positive TTG screens? If not, do you put these patients on a gluten-free diet as a trial?
3) Where and how many biopsies do you take to diagnose sprue? Do you always take biopsies in the duodenal bulb?
4) If you take duodenal biopsies, how long do you want the patient on gluten prior to the exam?
Now, let’s talk about gluten sensitivity:
1) If you take biopsies in patients with symptoms suggestive of sprue, and the biopsies are normal, but the patiens are improved on a gluten-free diet, what do you tell these patients? That they are sprue-variant? That they do not have sprue, but they are gluten sensitive?
2) Do you prescribe the same diet to these patients?
Please weigh in. I look forward to seeing your responses.