Ultrasonography of the parathyroid glands as an aid in differentiation of acute and chronic renal failure in dogs

Objective-To evaluate whether determination of parathyroid gland size by us e of ultrasonography is helpful in differentiating acute renal failure (ARF ) from chronic renal failure (CRF) in dogs. Design-Prospective study. Animals-20 dogs with renal failure in which serum creatinine concentration was at least 5 times the upper reference limit. Seven dogs had ARF, and 13 dogs had CRF. Twenty-three healthy dogs were used as controls. Procedure-Dogs were positioned in dorsal recumbency for ultrasonographic ex amination of the ventral portion of the neck. A 10-MHz linear-array high-re solution transducer was used. The size of the parathyroid gland was determi ned by measuring the maximal length of the gland on the screen when it was imaged in longitudinal section. For comparison among groups, the longest li near dimension of any of the parathyroid glands of each dog was used. Results-Size of the parathyroid glands in the control dogs varied from 2.0 to 4.6 mm (median, 3.3 mm). In the dogs with ARF, gland size ranged from 2. 4 to 4.0 mm (median, 2.7), which was not significantly different from contr ols. In dogs with CRF, the glands were more distinctly demarcated from the surrounding thyroid tissue, than those of controls and dogs with ARF Sizes ranged from 3.9 to 8.1 mm (median, 5.7 mm), which was significantly larger, compared with controls and dogs with ARF. Conclusions and Clinical Relevance-in dogs with severe azotemia, ultrasonog raphic examination of the parathyroid glands was helpful in differentiating ARF from CRF. Size of the parathyroid glands appeared to be related to bod y weight.