Evaluation of urinary glycosaminoglycan (GAG) levels and ultrasonographic findings in lower urinary system diseases (FLUTD) of Van cats

Altan Y. Evaluation of Urinary Glycosaminoglycan (GAG) Levels and Ultrasonographic Findings in Lower Urinary Tract Diseases (FLUTD) in Van Cats, Van Yüzüncü Yıl University, Institute of Health Sciences, Department of Internal Veterinary Medicine, Ph.D. Thesis, Van 2025. This study was conducted to determine the role of urinary GAG levels and ultrasound findings in the diagnosis of FLUTD in Van cats by identifying anamnesis, clinical examination, hematological, biochemical, urinalysis, radiographic, and ultrasonographic examination findings, particularly focusing on urinary GAG levels and USG findings. The animal material of the study consisted of a total of 35 Van cats, with 25 diagnosed with FLUTD and 10 healthy Van cats as the control group. Detailed anamnesis information and general clinical examination findings of the cats were recorded and evaluated. It was determined that 24% of the cats in the patient group had urethral obstruction, and all of these cats were male. In this group, the body temperature, respiratory and heart rates were high, and the changes in body temperature and respiratory rate were statistically significant (p<0.05). Hematological parameters such as WBC, %Eo, RBC, and Hb were found to be high and statistically significant, while no significant difference was observed in other hematological parameters. Serum Alb levels were high, and Na, Cl, and Mg levels were low; these changes were statistically significant, while differences in other biochemical parameters were not significant. The physical, chemical, and microscopic examinations of urine, as well as urinary GAG levels, were also assessed. In the microscopic examination of urine, 64% of the patient group had crystals. Among these, 68.75% had struvite, 12.5% had calcium oxalate, and 18.75% had both struvite and calcium oxalate crystals. Direct radiographic examination revealed urinary stones in the urethra of 1 cat and in the bladder of 2 cats, totaling 3 cats. In the ultrasonographic examination, no pathological findings were detected in 32% of the cats' bladders. Crystals were detected in 44% of the bladders, blood clots in 12%, bladder wall thickening in 24%, plaques in the urethra in 12%, and uroliths in the bladder and urethra in 12%. Urinary GAG levels were found to be significantly lower in the patient group. In conclusion, this is the first detailed study on FLUTD in Van cats, and despite the difficulties in material procurement and observations made, it was found that FLUTD is less common in Van cats, with the disease being more prevalent in male and neutered cats. Although some changes were detected in hematological and biochemical parameters and urine analyses, these changes did not provide significant clues for the definitive diagnosis of the disease. Ultrasonographic examination findings were particularly useful in identifying some etiological factors of FLUTD, and significant decreases in urinary GAG levels were observed in diseased animals, suggesting that this parameter could be an important indicator of the presence of the disease.