Exploratory single blind study on polarising and light microscopic appearance of crystals of commonly prescribed drug

Abstract

Background: It is not unusual for the pathologist to encounter various drug crystals in urine sediment which are morphologically different from the ones in his cognitive domain. Paucity of literature on crystals of all the drugs, makes it difficult to identify them. This study aims at exploring the microscopic appearance of crystals of common drugs. Material and Methods: Forty common drugs administered orally were included for the study. These drugs were mixed with distilled water on a slide, coverslipped and observed by two pathologists who were blinded. Of which one was a telepathologist who reported on images sent. Results: Crystals varied in their appearance and birefringence, few resembled architecture of known structures in urine sediment. Acetaminophen with hexagonal architecture resembled cysteine, broad colourless rectangular ceftriaxone crystals mimicked waxy cast. No definite answer was available for few, These data along with the light and polarising microscopic features are discussed in detail. Conclusion: Crystals of unusual appearance should alarm the pathologist to think of a drug and alert the physician in case of drugs causing renal damage.