A small bowel biopsy of a patient with lactose intolerance would show normal histology as seen in Figure D.
Lactose intolerance is the inability to digest lactose, a common disaccharide, due to a deficiency of lactase. It causes osmotic diarrhea whenever lactose is ingested and produces characteristic belly pain, flatulence, and diarrhea. It is commonly diagnosed if administration of lactose produces symptoms and if glucose rises <20 mg/dL following administration. Treatment is avoidance of dairy products and lactase replacement prior to meals as needed.
Swagerty et al. review the pathophysiology, diagnosis, and management of lactose intolerance. They state that the diagnosis can usually be made with a careful history supported by dietary manipulation, and if necessary, can be confirmed by using a breath hydrogen or lactose tolerance test. Treatment consists primarily of avoiding lactose-containing foods. Lactase enzyme supplements may be helpful.
Ji et al. perform a population based study to examine the association between lactose intolerance and the risk of lung, breast, and ovarian cancers. Of the 22,788 individuals with lactose intolerance, the risks of lung (SIR=0.55), breast (SIR=0.79), and ovarian (SIR=0.61) cancers were significantly decreased. They hypothesize that the protective effects against these cancers may be related to their specific dietary pattern.
Figures are described in the incorrect answer key below.
Answer 1: Figure A demonstrates the small bowel histology that would be observed in celiac sprue. Note the blunting of the villi and crypt hyperplasia.
Answer 2: Figure B demonstrates the small bowel histology that would be observed in Whipple's disease. Note the PAS-positive foamy macrophages in intestinal lamina propria.
Answer 3: Figure C demonstrates the small bowel histology that would be observed in Crohn's disease. Note the non-caseating granuloma which is characteristic of Crohn's.
Answer 5: Figure E demonstrates the large bowel histology that would be observed in ulcerative colitis. Note the crypt abscesses and ulcers.
Swagerty DL Jr, Walling AD, Klein RM. Lactose intolerance. Am Fam Physician. 2002 May 1;65(9):1845-50. Review. Erratum in: Am Fam Physician. 2003 Mar 15;67(6):1195. PubMed PMID: .
PMID:12018807 (Link to Abstract)
Ji J, Sundquist J, Sundquist K. Lactose intolerance and risk of lung, breast and ovarian cancers: aetiological clues from a population-based study in Sweden. Br J Cancer. 2015 Jan 6;112(1):149-52. doi: 10.1038/bjc.2014.544. Epub 2014 Oct 14. PubMed PMID: .
PMID:25314053 (Link to Abstract)