Jb. Marshall et al., CHRONIC, UNEXPLAINED DIARRHEA - ARE BIOPSIES NECESSARY IF COLONOSCOPYIS NORMAL, The American journal of gastroenterology, 90(3), 1995, pp. 372-376
Objective: We sought to determine the frequency of clinically importan
t histological abnormalities in patients with chronic, unexplained dia
rrhea who had macroscopically normal colonic endoscopies. Methods: Of
855 consecutive patients undergoing colonoscopy (595 cases) or flexibl
e proctosigmoidoscopy (260 cases) by one endoscopist, biopsies were ta
ken in 111 cases of unexplained diarrhea of at least 4-6 weeks duratio
n in which the colorectal mucosa appeared grossly normal. All biopsies
were blindly reviewed by one pathologist. Results: In this group of p
atients with macroscopically normal colons, we identified no cases of
Crohn's disease or ulcerative colitis or any definite cases of collage
nous colitis (CC) or lymphocytic colitis (LC). There was one case clas
sified as ''possible CC'' and 13 cases classified as ''some features o
f LC.'' There were five cases of melanosis coli, one case of cytomegal
ovirus colitis (in an immunosuppressed patient), and one case of radia
tion injury. Ninety-one cases were classified as no pathological diagn
osis or minimal histological change. Patients with abnormal histology
were contacted to see if they had persistence or resolution of diarrhe
a. For the cases of ''possible CC'' and ''some features of LC,'' diarr
hea had resolved spontaneously in the majority. Interesting to note, o
nly one of the five melanosis coli patients admitted to laxative use,
raising the question of surreptitious abuse. Conclusions: We conclude
that the yield of biopsies in diarrhea patients with macroscopically n
ormal colons at endoscopy is low. It may be reasonable to obtain biops
ies in patients with relatively severe or debilitating symptoms, with
diarrhea that sounds ''organic'' (e.g., nocturnal stools, frequent wat
ery stools, weight loss, elevated sedimentation rate), or in patients
who are immunosuppressed. When biopsies are taken at colonoscopy, we s
uggest taking about six from throughout the colon and placing them int
o just one specimen container to help minimize costs.