Conjunctival impression cytology in children with persistent diarrhea as indicator of pre-clinical vitamin A deficiency.

Children with persistent diarrhea may be at a higher risk of developing vitamin A deficiency. Impression cytology of the conjunctiva has been shown to be a simple and objective diagnostic test for detection of early, physiologically significant vitamin A deficiency. We studied, changes in conjunctival impression cytology using millipore HAWG filter paper in 25 children aged less than 5 years suffering from persistent diarrhea, who had no ocular manifestations of vitamin A deficiency (Group I). Twenty five age matched healthy children constituted the control group (Group II). Seventeen of the 25 children with persistent diarrhea (68%), showed the following abnormalities: (i) the shape of the epithelial cells were abnormal, and (ii) goblet cells were absent. The study could be repeated after 2 weeks of administration of vitamin A in 7 children. Reappearance of PAS-positive mucous glycoproteins and presence of normal epithelial cells was demonstrated in all 7 children retested. This test can prove to be of significant value in assessment of response to vitamin A therapy. This study shows that children with persistent diarrhea appear to be at high risk for developing vitamin A deficiency, which can be detected by the technique of conjunctival impression cytology. This is a cheap and reliable method of detecting preclinical vitamin A deficiency which can be performed by a pediatrician in the office laboratory.