Struvite Urolithiasis in Long–Evans Rats

摘要

Struviteurinarycalculi,whicharecomposedofmagnesium,ammonium,andphosphate,cancausecomplicationsincludingsepsisandrenalfailure.Struvitecalculiwereidentifiedwithintheurinarybladderandrenalpelvisof2Long-Evansratsthatdiedwithindaysafterarrivalfromacommercialvendor.Theremainingratsintheshipmentwerescreenedbyphysicalexamination,radiography,andultrasonography,revealinganadditional2animalsthatwereclinicallyaffected.Theseratswereeuthanized,necropsied,andyieldedsimilarfindingstothosefromthefirst2rats.Inaddition,urinesampleshadanalkalinepHandcontainednumerousbacteria(predominantlyProteusmirabilis),leukocytes,andcrystals.Allcalculiwerecomposedcompletelyofstruvite.Another7ratsintheshipmenthadalkalineurinewiththepresenceofbloodcells;6oftheseratsalsohadabundantstruvitecrystals,andP.mirabiliswasculturedfromtheurineof3rats.Furtherinvestigationbythevendoridentified2of100ratswithstruvitecalculifromthesamecolony.Althoughnospecificcausecouldbeimplicated,thefactthatalltheaffectedratscamefromthesamebreedingareasuggestsageneticorenvironmentaltriggeringevent;acontributionduetodietcannotberuledout.Ourfindingssuggestthattheaffectedratshadmetabolicdisturbancescoupledwithbacterialinfectionthatpredisposedthemtodevelopstruvitecalculi.Duringsuddenincreasesofstruviteurinarycalculicasesinrats,urineculturesfollowedbyappropriatesurgicalinterventionandantibiotictherapyiswarranted.Additionalfactors,includingdiet,meritattentionaswell.