Objectives

The objective of this study was to investigate the relationship between serum parathyroid hormone (PTH) level and the development of chronic renal failure (CRF) in cats.

Materials & Methods

Twenty-four cats presented to Small Animal Hospital, Faculty of Veterinary Science, Chulalongkorn University between January 2002 to January 2003 was studied. Cats divided into two groups. The first group (11 cats) was primarily diagnosed by the veterinarians to have chronic renal failure whose blood urea nitrogen (BUN) concentrations were more than 40 mg/dl, serum creatinine level of more than 2.1 mg/dl, and urine specific gravity of less than 1.035. The second group was the control group (13 cats) who came for vaccination at the same hospital within the same period. Cats were followed for 60 days after first diagnosis. The complete blood count, blood chemistry, electrolytes, and parathyroid hormone level were measured on the day 0, 14, 30 and 60.

Results

The results showed that CRF cats revealed significantly lower in red blood cells, hemoglobin, and pack cell volume than control cats (p<0.05). Blood level of BUN, creatinine, and phosphorus were significantly higher (p<0.05) in CRF group, which showed azotemia and hyperphosphatemia. However, ionized calcium level in CRF group was significantly lower (p<0.05) than control group on day 0 and 14 which may trigger the release of parathyroid hormone. The plasma PTH levels in CRF group were significantly increased (p<0.05) compared with the control group indicated hyperparathyroidism. Bicarbonate level in CRF cats was significant lower (p<0.05) on day 60.

Conclusion

This study reveals that cats with chronic renal failure often developed anemia, azotemia, hyperphosphatemia and renal secondary hyperparathyroidism especially at late stage of CRF.