Urinalysis findings in dogs: A preliminary clinical evaluation of fifteen cases

Introduction

Urinalysis is among the most commonly performed diagnostic procedures in small animal practice and serves as a valuable tool for the evaluation of urinary tract disorders, renal disease, metabolic abnormalities, and systemic illnesses (Kaneko et al., 2008) [4] . A complete urinalysis comprises physical, chemical, and microscopic examination of urine and provides important information regarding glomerular filtration, tubular function, inflammatory processes, and urinary tract integrity (Stockham and Scott, 2008) [7] . Proteinuria is one of the most clinically significant abnormalities encountered in canine urinalysis and may arise from glomerular disease, tubular dysfunction, urinary tract inflammation, or hemorrhage (Grauer, 2005) [3] . Likewise, hematuria and pyuria are commonly associated with bacterial cystitis, urolithiasis, trauma, and neoplastic conditions affecting the urinary tract (Bartges, 2004) [1] . Urine pH plays an important role in crystal formation and bacterial growth. Alkaline urine favors precipitation of magnesium ammonium phosphate (struvite) crystals and is frequently associated with urinary tract infections caused by urease-producing bacteria such as Staphylococcus spp. and Proteus spp. (Osborne et al., 1999) [6] . Microscopic examination of urinary sediment further enhances diagnostic accuracy through identification of erythrocytes, leukocytes, epithelial cells, casts, microorganisms, and crystals (Cowell et al., 2008) [2] . The present study was undertaken to document the urinalysis findings observed in canine clinical cases and to correlate chemical and microscopic abnormalities indicative of urinary tract disease.

Materials and Methods

Study Design

A descriptive observational study was conducted on fifteen canine urine samples submitted to the clinical pathology laboratory for routine diagnostic evaluation.

Urine Collection

Urine samples were collected using the following methods: Samples were analyzed immediately after collection to minimize cellular degeneration and crystal artifact formation (Bartges, 2004) [1] .

Physical Examination

Urine specific gravity was measured using a refractometer. Gross appearance and color were recorded whenever applicable.

Chemical Examination

Chemical analysis was performed using commercially available urine reagent strips for determination of:

Microscopic Examination

Urine samples were centrifuged at approximately 1500-2000 rpm for 5 minutes. The supernatant was discarded and the sediment resuspended before examination under light microscopy.

The following parameters were recorded:

• White blood cells (WBCs) Photomicrograph revealing marked erythrocyturia with scattered epithelial cells, struvite crystals and cellular debris.

Results

Urinalysis

The findings are consistent with lower urinary tract inflammation and correlate with the elevated RBC counts observed during sediment examination.

Discussion

Proteinuria was identified in 60% of examined urine samples and constituted the most prevalent abnormality. Proteinuria may occur secondary to renal disease; however, inflammatory and hemorrhagic processes affecting the urinary tract can also contribute significantly to urinary protein excretion (Grauer, 2005) [3] .

Hematuria was detected in one-third of examined samples. Similar findings have been reported in dogs suffering from bacterial cystitis, urolithiasis, urinary tract trauma, and neoplasia (Bartges, 2004) [1] . The presence of 20-40 RBCs/HPF observed in this study suggests active bleeding within the urinary tract.

Marked pyuria was one of the most notable microscopic findings. Leukocyte counts approaching 50-60 WBCs/HPF strongly indicate inflammatory processes and are frequently associated with bacterial urinary tract infection (Ling, 1984) [5] . The simultaneous presence of proteinuria, pyuria, and nitrite positivity in several samples further supports this interpretation. Alkaline urine pH was observed in 40% of cases. Increased urine pH may result from dietary influences; however, bacterial urease activity is a well-recognized cause of urine alkalinization in dogs (Osborne et al., 1999) [6] . The occasional presence of struvite crystals in alkaline urine further supports this association. Clusters of transitional epithelial cells identified in three samples likely reflect increased urothelial turnover associated with inflammation. Similar observations have been reported in canine lower urinary tract disorders (Cowell et al., 2008) [2] . The photomicrographic findings corroborated the laboratory data and provided visual evidence of hematuria, pyuria, and epithelial cell shedding. Together, these observations indicate that inflammatory lower urinary tract disease was a prominent feature among the dogs evaluated in the present study.

The major limitations of this study include the relatively small sample size and the absence of urine culture and antimicrobial susceptibility testing, which prevented definitive confirmation of bacterial infection.

Conclusion

The present investigation demonstrated that proteinuria, pyuria, hematuria, elevated urine specific gravity, and alkaline urine were the most common abnormalities detected in canine urine samples. Microscopic examination revealed abundant erythrocytes, leukocytes, transitional epithelial cells, and occasional struvite crystals. These findings are suggestive of lower urinary tract inflammation and possible bacterial urinary tract infection. Routine urinalysis remains an effective diagnostic tool for the early detection and monitoring of urinary tract disorders in dogs.

References

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