Prevalence and features of early diagnosis of chronic kidney disease in cats

Chronic kidney disease (CKD) in cats is a long-term process characterized by the irreversible loss of metabolic, endocrine, and excretory functions of the kidneys, usually due to the development of nephrosclerosis. The overall prevalence of CKD in cats is approximately 2 % to 4 % and increases to 30–40 % in cats older than 10 years. It is the second leading cause of death. CKD can occur due to polycystic disease, pyelonephritis, glomerulonephritis, neoplasia, amyloidosis, viral infections, urolithiasis and is the most common cause of hypertension in cats, accounting for 20 to 60 % of cases. Cats often have a combined course of hyperthyroidism and CKD. For CKD in cats, hyporexia (64.8 %), polyuria and polydipsia (56.7 %), anemia of mucous membranes (67.5 %), impaired coordination of movements (35 %), vomiting (43 %), ulcerative stomatitis were most often noted (37.8 %). Polyuria, polydipsia, polyphagia, nausea, and vomiting were detected in cats with combined course of hyperthyroidism. It was established that the 1st stage of CKD passes without pronounced changes in the blood serum but with the preservation of the symptoms of the disease. The concentration of cystatin C in the blood serum of cats with impaired kidney function at all stages was higher (P > 0.001) compared to clinically healthy animals by 13.9, 34.7, and 73.6 %. In cats at II-IV stages, a significant increase in azotemia was established, accompanied by an increase in creatinine and urea content (P > 0.001) compared to clinically healthy animals. A clear tendency to decrease the rate of glomerular filtration was established at different stages of CKD: at II – 115.8 ± 1.43 ml/min/1.73; the third – 101.7 ± 1.02; IV – 83.9 ± 1.20 ml/min/1.73. The level of SDMA in the blood serum of cats was higher (P < 0.001) in stage II (21.30 ± 0.64 μg/dl), III (30.96 ± 1.17 μg/dl), and IV (91.87 ± 12.54 μg/dL) compared to the control group. A violation of mineral and bone metabolism was established, even in the early stages of the disease, which was characterized by a decrease (Р < 0.001) in the level of total calcium and an increase in the level of inorganic phosphorus and potassium in the blood serum of cats. In the combined course of CKD and hyperthyroidism, an increase (Р < 0.001) in the level of the total hormone T4 in blood serum was found in diseased cats in stages II and IV. Arterial hypertension was established in 16 cats, the risk of which increased from moderate (148 ± 4.7/98 ± 3.8 mmHg at the II stage of the course) to high at the IV stage (188 ± 3.8 mmHg. and 116.7 ± 4.06 mm Hg). The development of anemic syndrome, microcytic hyperchromic anemia, and changes in the physical properties and chemical composition of urine were established.