Scanning electron microscopy study of small bowel biopsies in chronic diarrhoea in chlldhood

Abstract

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.