EN14 - Ultrasound of Parathyroid Glands and Correlation with Parathyroid Hormone Measurements in Feline Chronic Kidney Disease

Abstract: Background - Calcium and phosphate dysregulation is frequent in cats with chronic kidney disease (CKD). Although the subsequent oversecretion of parathyroid hormone (PTH) may induce parathyroid glands (PTGs) hyperplasia in these cats, data concerning its characterization on ultrasound is scarce. Hypothesis/Objectives - This study aimed to characterize PTGs assessed by ultrasound and compare imaging findings with PTH concentrations in CKD cats. We hypothesize that CKD cats have larger PTGs and higher PTH concentrations. Animals - Twenty-two client-owned cats were recruited: 11 healthy and 11 cats with CKD. Methods - A prospective cohort study was conducted. At two timepoints (T0 and T4-6 months), healthy and CKD cats underwent cervical ultrasound using a high-frequency transducer (15-22 MHz), aiming to identify structures compatible with PTGs, with their number and dimensions being registered. PTH serum concentrations were measured with a validated immunoenzymatic assay. Ultrasound parameters and PTH concentrations were subjected to comparative statistical analysis. Results - Identified PTGs were higher in number (p = 0.014 and p = 0.013, for T0 and T4-6months, respectively) and significantly larger (p = 0.036 for minor axis at T4-6months) in CKD cats. PTH concentrations were higher in CKD cats, despite no significant differences found between groups at both timepoints (p = 0.078 and p = 0.110, respectively). There was no significant correlation between PTGs dimensions and PTH serum concentrations. Conclusions and Clinical Importance - Although no correlation was found with PTH concentrations, CKD cats have larger and more easily identified PTGs on cervical ultrasound, using a high-frequency transducer.