In thi, study wc have compared the results ot
Scanning Electron Microscopy (SEM) with Light- and
Stereomicroscopy in a series of small bowel biop\ies in
children.
In 9 cases displaying features of partial or wbtotal
atrophy, Light and Dissecting-Microscopy yiclded
similar results. The distinction between coeliac and noncoeliac
chronic diari-hoen was only possible on cliiiical
grounds, and by the iininunological detection of specific
antibodies. On SEM however coeliac patients showed
characteristic alterations consisting of: absence of villi:
prominent crypt outlets resulting in a mosaic appearance:
concentric furrows running al1 around the openings; and
downy brush feature at higti power. The microvilli were
loosely distributed and had an irregular pleomorphic
outline; they often displayed a druinstick swelling of tlic
tip and were bent. In contra5t. non-coeliac chronic
diarrhoea cases were characterized bv a thick mucous
layer on the mucosa1 surface, that made it impossible to
visualize further chan~es. U
Peculiar \iascular changes in Iymphangiectasia and in
sickle beta thalasseinia could be detected only by Liglit
Microscopy. In addition, in the lymphangiectasia ca\e
SEM allowed the detection of enteroadherent bacteria:
and in the lambliasi, case, of pseudomembi-rine\.
Absence of glycocalyx was noted both in controls and
in patients.
The results of this study point to a diagnostic utility of SEM particularly in the differential diagnosis of chronic
diarrhoea; moreover they suggest tliat enteroadherent
bacteria may not be pathogenic and that the absence of
glycocalyx is not specific for allergic enteropathy as
previously claimed