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Chapter 29 : Examination of Other Specimens from the Intestinal Tract and the Urogenital System
Symptoms that have been attributed to the pinworm infection, particularly in children, include nervousness, insomnia, nightmares, and even convulsions. In some cases, perianal granulomas may result. If the amount of material limits the examination to one procedure, the use of polyvinyl alcohol (PVA) fixative is highly recommended. Many physicians performing sigmoidoscopy procedures do not realize the importance of selecting the proper fixative for material to be examined for parasites. One of the organisms most strongly suspected when sigmoidoscopy is performed is Entamoeba histolytica, whose morphology is normally seen from the permanent stained smear; however, this identification assumes that RBCs are seen within the cytoplasm of the trophozoites. Duodenal drainage material can be submitted for examination as direct or concentration wet mounts or permanent stained smears, techniques that may reveal the parasites. Examination of urinary sediment is indicated in certain filarial infections. The occurrence of microfilariae in urine has been reported with increasing frequency in Onchocerca volvulus infections in Africa. The identification of Trichomonas vaginalis is usually based on the examination of a wet preparation of vaginal and urethral discharges and prostatic secretions or urine sediment. The efficiency of the polycarbonate membrane filtration technique for detecting Schistosoma haematobium eggs in urine is increased by using a pore size of 14 μm and the suction of a water jet pump.