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Objective—

To compare a technique in which samples obtained from selected venous sites are analyzed for parathyroid hormone (PTH) concentration versus usefulness of cervical ultrasonography for localizing primary hyperparathyroidism (PHP) in dogs.

Design—

Prospective study.

Animals—

12 dogs with PHP.

Procedure—

For each dog, blood samples were collected from the left and right jugular veins and 1 cephalic vein for determination of serum PTH concentration. Ultrasonography of the neck was performed in each dog. Each dog underwent exploratory surgery of the neck. Abnormal appearing parathyroid tissue was removed. Dogs were included in the study if serum calcium concentration decreased within 12 hours after surgery, hypercalcemia completely resolved within 96 hours after surgery, and serum calcium concentration was maintained within the reference range for at least 6 months after surgery.

Results—

Serum PTH concentrations from the 3 veins were similar in 11 of 12 dogs with PHP. In 1 dog, the serum PTH concentration from the jugular vein ipsilateral to a parathyroid adenoma was greater than that from the contralateral jugular or cephalic vein. Ultrasonography correctly identified a parathyroid mass and its location in 10 of 11 dogs with a solitary abnormal parathyroid gland and in 1 dog in which both parathyroid glands were enlarged.

Clinical Implications—

Surgeons may benefit from knowing the location of abnormal parathyroid tissue in dogs with PHP before surgical exploration. Ultrasonography has potential value for identifying and localizing abnormal parathyroid tissue, whereas sample collection from selected sites for PTH analysis is not likely to be helpful. (J Am Vet Med Assoc 1997;211:54–56)

Free access
in Journal of the American Veterinary Medical Association

SUMMARY

Chemical and cytologic effects and bactericidal activity of gentamicin in septic synovial fluid were evaluated in an experimental model of infectious arthritis in horses. Septic arthritis was induced by inoculation of approximately 7.5 × 106 colony-forming units of Escherichia coli into 1 antebrachiocarpal joint in each of 16 clinically normal adult horses. Clinical signs of septic arthritis were evident 24 hours after inoculation. Horses were allotted to 3 groups: group-1 horses (n = 5) each were given 150 mg of gentamicin (50 mg/ml; 3 ml) intra-articularly (ia); group-2 horses (n = 5) each were given 2.2 mg of gentamicin/kg of body weight, iv, every 6 hours; and group-3 horses (n = 6) each were given buffered gentamicin, consisting of 3 mEq of sodium bicarbonate (1 mEq/ml; 3 ml) and 150 mg of gentamicin (50 mg/ml; 3 ml), ia. Synovial fluid specimens were obtained at posttreatment hour (pth) 0, 0.25, 1, 4, 8, 12, and 24 via an indwelling intra-articular catheter. Synovial fluid pH was evaluated at pth 0, 0.25, and 24. Microbiologic culture and cytologic examination were performed on synovial fluid specimens obtained at pth 0 and 24, and gentamicin concentration was measured in all synovial fluid specimens.

At pth 0, E coli was isolated from synovial fluid specimens obtained from all horses. Synovial fluid pH was lower (range, 7.08 to 7.16) and wbc count was higher (range, 88,000 to 227,200 cells/μl) and predominantly neutrophilic (95 to 99%) at pth 0 than before inoculation. Synovial fluid pH was lowered further (mean, pH 6.63) after ia administration of gentamicin in group-1 horses; mean pH remained unchanged (7.07) after buffered-gentamicin administration in group-3 horses. At pth 0.25, mean peak synovial fluid gentamicin concentration in horses of groups 1 and 3 (4,745 and 6,190 μg/ml, respectively) was 1,000 times greater than that in group-2 horses (5.1 μg/ml) at the same time. Synovial fluid gentamicin concentration in group-1 and group-3 horses was always greater than that in group-2 horses and remained greater than a minimal inhibitory concentration of gentamicin (2 μg/ml) against many common equine bacterial pathogens for at least 24 hours after injection. Further, the calculated apparent half-life and clearance of gentamicin in synovial fluid calculated after ia administration were similar in horses of groups 1 and 3. By pth 24, E coli could not be isolated from synovial fluid specimens obtained from group-1 horses. However, moderate to heavy growth of E coli was isolated from synovial fluid specimens obtained at pth 24 from horses in groups 2 and 3 (80 and 66%, respectively).

In selected cases, ia administration of unbuffered gentamicin may be a useful supplement to drainage, lavage, and systemic antibacterial and anti-inflammatory treatment in horses with naturally acquired infectious arthritis.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To determine the effects of parathyroid hormone (PTH) depletion on dogs with induced chronic renal failure.

Animals

2 groups of 26 mixed-breed dogs of both sexes (13 were parathyroidectomized [PTX] and 13 had sham surgery).

Procedure

After surgical reduction of renal mass and PTX, dogs were selected for a 24-month period of study and monitored for clinical, hematologic, blood biochemical, and organ function status. On development of uremia or after 24 months, dogs were euthanatized, and tissues were examined.

Results

Higher survival rate and smaller decrement in renal function (glomerular filtration rate) were observed in PTX dogs, compared with those that had sham surgery, but values did not reach statistical significance. The PTX dogs remained hypocalcemic during the study and had lower serum Ca2+ × P product values. Regardless of parathyroid state, survivors and fatalities could be separated on the basis of serum Ca2+ × P product values. Parathyroidectomy did not prevent renal deposition of calcium, and renal lesions were poorly correlated with renal cortical calcium concentration. Abnormalities reported in dogs with renal failure, which were attributed to PTH (glucose intolerance, pulmonary hypertension), were not observed in PTX dogs or those that had sham surgery.

Conclusions and Clinical Relevance

PTX had beneficial effects, but these were mediated via changes in mineral homeostasis rather than via direct effects of PTH. Results attributable to PTX were similar to those previously obtained by dietary restriction of phosphate intake. (Am J Vet Res 1997;58:188–195)

Free access
in American Journal of Veterinary Research

Summary

The medical records of 7 hypercalcemic cats with primary hyperparathyroidism were evaluated. Mean age was 12.9 years, with ages ranging from 8 to 15 years; 5 were female; 5 were Siamese, and 2 were of mixed breed. The most common clinical signs detected by owners were anorexia and lethargy. A cervical mass was palpable in 4 cats. Serum calcium concentrations were 11.1 to 22.8 mg/dl, with a mean of 15.8 mg/dl calculated from each cat's highest preoperative value. The serum phosphorus concentration was low in 2 cats, within reference limits in 4, and slightly high in 1 cat. The bun concentration was > 60 mg/dl in 2 cats, 31 to 35 mg/dl in 2 cats, and < 30 mg/dl in 3 cats. Abnormalities were detected in serum alanine transaminase, aspartate transaminase, and alkaline phosphatase activities from 2 or 3 cats. Parathormone (pth) concentrations were measured in 2 cats before and after surgery. The preoperative pth concentration was within reference limits in 1 cat and was high in 1 cat. The pth concentrations were lower after surgery in both cats tested. A solitary parathyroid adenoma was surgically removed from 5 cats, bilateral parathyroid cystadenomas were surgically resected in 1 cat, and a parathyroid carcinoma was diagnosed at necropsy in 1 cat. None of the cats had clinical problems with hypocalcemia after surgery, although 2 cats developed hypocalcemia without tetany, one of which was controlled with oral administration of dihydrotachysterol and the other with oral administration of 1,25 dihydroxyvitamin D. All 5 of the cats that underwent removal of an adenoma were alive at least 240 days after surgery. Four of these 5 cats were normocalcemic at the last examination. The cat that had bilateral cystadenomas was lost to follow-up evaluation 110 days after surgery. One of the cats with a parathyroid adenoma was reevaluated 569 days after the first surgery. It was found to be hypercalcemic (21.5 mg/dl), subsequently died, and was identified as having a parathyroid adenoma and a parathyroid carcinoma on histologic evaluation of tissue removed from the neck at necropsy.

Free access
in Journal of the American Veterinary Medical Association

Objective

To evaluate the efficacy, feasibility, and safety of ultrasound-guided chemical ablation of parathyroid masses in dogs with primary hyperparathyroidism.

Design

Prospective clinical trial.

Animals

8 dogs.

Procedure

In all dogs, a solitary parathyroid mass was evident ultrasonographically. Dogs were anesthetized with propofol, and a 27-gauge needle was directed into the parathyroid mass under ultrasound guidance. Ethanol (96%) was injected into the mass until there was evidence of diffusion of fluid throughout the mass. Serum total calcium, ionized calcium, phosphorus, and parathyroid hormone (PTH) concentrations were monitored daily for 5 to 7 days after the ablation procedure and again 1, 3, and 6 months after the procedure. Dogs were also monitored for adverse effects. Follow-up ultrasonography was performed 5 days and 1 month after the ablation procedure.

Results

One injection was required in 7 dogs, and 2 injections were required in 1. Serum total and ionized calcium concentrations were within reference ranges within 24 hours after treatment in 7 dogs and within 5 days in 1 dog. Serum PTH concentration decreased and serum phosphorus concentration increased within 24 hours after treatment in all 8 dogs. Transient hypocalcemia developed in 4 dogs during the first 5 days after treatment, but only 1 dog required treatment for hypocalcemic tetany. Hypercalcemia recurred in 1 dog 1 month after the procedure and surgical removal of the parathyroid mass was required. Other adverse effects were not reported.

Conclusions and Clinical Relevance

Ultrasound-guided chemical ablation of parathyroid masses is a safe and effective alternative to surgery for dogs with primary hyperparathyroidism. (J Am Vet Med Assoc 1999;215:217–221)

Free access
in Journal of the American Veterinary Medical Association

dogs, our research group determined that metabolic acidosis directly stimulates PTH secretion, that the acidosis-induced increase in arterial Ca 2+ concentration reduces the magnitude of PTH stimulation during metabolic acidosis, and that metabolic

Full access
in American Journal of Veterinary Research

Primary hyperparathyroidism in dogs is most commonly caused by autonomous and excessive secretion of PTH from a single parathyroid gland adenoma. 1,2 Less commonly, dogs with PHPT may have multiple parathyroid gland adenomas, a parathyroid gland

Full access
in Journal of the American Veterinary Medical Association

Extracellular iCa concentrations are regulated by a complex homeostatic system that includes 3 hormones (PTH, calcitonin, and 1,25-dihydroxyvitamin D 3 ); 3 body systems (the bones, intestines, and kidneys); and CaRs in the chief cells of the

Full access
in American Journal of Veterinary Research

smear examination, serum biochemistry panel, urinalysis, and parathyroid hormone (PTH) and PTH-related protein (PTH-rp) testing as well as abdominal and thoracic imaging, cervical ultrasonography, and survey bone radiographs. While there are many

Free access
in Journal of the American Veterinary Medical Association

the initial examination on day 1 was submitted to another laboratory l for determination of ionized calcium and PTH concentrations. The ionized calcium concentration was 0.47 mmol/L (reference interval for dogs, 1.25 to 1.45 mmol/L; reference interval

Full access
in Journal of the American Veterinary Medical Association