COMPARISON OF RESULTS OF HORMONAL ANALYSIS OF SAMPLES OBTAINED FROM SELECTED VENOUS SITES VERSUS CERVICAL ULTRASONOGRAPHY FOR LOCALIZING PARATHYROID MASSES IN DOGS

Objective-To compare a technique in which samples obtained from select ed venous sites are analyzed for parathyroid hormone (PTH) concentrati on versus usefulness of cervical ultrasonography for localizing primar y hyperparathyroidism (PHP) in dogs. Design-Prospective study. Animals -12 dogs with PHP. Procedure-For each dog, blood samples were collecte d from the left and right jugular veins and 1 cephalic vein for determ ination of serum PTH concentration. Ultrasonography of the neck was pe rformed in each dog. Each dog underwent exploratory surgery of the nec k. Abnormal appearing parathyroid tissue was removed. Dogs were includ ed in the study if serum calcium concentration decreased within 12 hou rs after surgery, hypercalcemia completely resolved within 96 hours af ter surgery, and serum calcium concentration was maintained within the reference range for at least 6 months after surgery. Results-Serum PT H concentrations from the 3 veins were similar in 11 of 12 dogs with P HP. In 1 dog, the serum PTH concentration from the jugular vein ipsila teral to a parathyroid adenoma was greater than that from the contrala teral jugular or cephalic vein. Ultrasonography correctly identified a parathyroid mass and its location in 10 of 11 dogs with a solitary ab normal parathyroid gland and in 1 dog in which both parathyroid glands were enlarged. Clinical Implications-Surgeons may benefit from knowin g the location of abnormal parathyroid tissue in dogs with PHP before surgical exploration. Ultrasonography has potential value for identify ing and localizing abnormal parathyroid tissue, whereas sample collect ion from selected sites for PTH analysis is not likely to be helpful.