title: Silicon dioxide calculi in humans in the absence of silicate antacid medication.
abstract: The occurrence of silicon dioxide in human urinary calculi is more common than generally believed. During a 3 year study we have analyzed about 750 human urinary calculi using the scanning electron microscope and x-ray crystallographic methods. Silicon dioxide of the alpha quartz variety was found to be the principal constituent in calculi from 5 male patients. Some of the patients were recurrent stone formers and 1 patient has previously produced a silicon dioxide calculus. In none of the 5 cases was there any history of gastric disorders or of any ingestion of antacids in the form of magnesium trisilicate. Some of the silica particles have a morphology typical of glacial sand.
mesh_terms: D000328:Adult; D000368:Aged; D000863:Antacids; D006801:Humans; D008274:Magnesium; D017633:Magnesium Silicates; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D012824:Silicic Acid; D012822:Silicon Dioxide / Q000032:analysis*; D014545:Urinary Calculi / Q000378:metabolism*; D014961:X-Ray Diffraction
chemical_list: D000863:Antacids; D017633:Magnesium Silicates; D012824:Silicic Acid; D012822:Silicon Dioxide; C001671:magnesium trisilicate; D008274:Magnesium