Composition and characteristics of urinary calculi from guinea pigs.
OBJECTIVE
To determine the mineral composition of calculi, anatomic locations of the calculi, and findings of urinalysis and bacteriologic culture of urine and calculi in guinea pigs with urolithiasis.


METHODS
Cross-sectional study.


METHODS
127 guinea pigs.


METHODS
Records of urinary calculi that had been submitted to the University of California Stone Laboratory from 1985 through 2003 were reviewed. In addition, submissions of urinary calculi for evaluation by the laboratory were prospectively solicited from 2004 through 2007. Prospectively obtained calculi were accompanied by a urine sample for urinalysis and bacteriologic culture and a completed questionnaire. All calculi were analyzed by use of polarized light microscopy and infrared spectroscopy. A subset of calculi was examined by means of x-ray diffractometry (XRD).


RESULTS
83% (43/52) of calculi from the laboratory database and 93% (70/75) of calculi that were prospectively solicited were composed of 100% calcium carbonate. Analysis via XRD confirmed that 5 of 6 calculi from a subset that had the greatest gross morphologic variation were composed of 100% calcite. Although many guinea pigs had received anti-microbials before bacteriologic cultures of urine were performed, Corynebacterium renale was isolated from 5 urine samples.


CONCLUSIONS
Contrary to findings of other studies, urinary calculi analyzed for the present study were most commonly composed of 100% calcium carbonate, and infrared spectroscopy or XRD was necessary to differentiate this mineral from others. Treatments, including diet and husbandry practices, should be developed to help prevent development of calcium carbonate calculi in guinea pigs.
Hawkins
Michelle G
MG
Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Ruby
Annette L
AL
Drazenovich
Tracy L
TL
Westropp
Jodi L
JL
D000821:Animal Feed / Q000009:adverse effects / Q000032:analysis; D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D002119:Calcium Carbonate / Q000032:analysis*; D003352:Corynebacterium / Q000302:isolation & purification*; D003430:Cross-Sectional Studies; D003460:Crystallization; D005260:Female; D006168:Guinea Pigs; D008297:Male; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods / Q000662:veterinary; D016482:Urinalysis / Q000379:methods / Q000662:veterinary*; D014545:Urinary Calculi / Q000737:chemistry / Q000175:diagnosis / Q000382:microbiology / Q000662:veterinary*; D052878:Urolithiasis / Q000175:diagnosis / Q000382:microbiology / Q000662:veterinary*; D014961:X-Ray Diffraction / Q000379:methods / Q000662:veterinary
D002119:Calcium Carbonate