Page 794 - Small Animal Internal Medicine, 6th Edition

766 PART VI Endocrine Disorders

and calcium. These calcium concentrations are above the Suggested Readings
level at which there is risk of clinical hypocalcemia and Feldman EC, et al. Canine and feline endocrinology. ed 4. St. Louis:
VetBooks.ir below the level at which hypercalciuria (risk of calculi forma- Johnston SA, Tobias KM. Veterinary surgery: small animal. St Louis:
Elsevier; 2015.
tion) or severe hypercalcemia and hyperphosphatemia (risk
of nephrocalcinosis and kidney failure) may occur. Mainte-
Elsevier Saunders; 2018.
nance therapy should be initiated once the hypocalcemic Primary Hyperparathyroidism
tetany is controlled with intravenous calcium therapy. The Arbaugh M, et al. Evaluation of preoperative concentrations of
onset of action of vitamin D varies depending on the formu- ionized calcium and parathyroid hormone as predictors of hypo-
lation of vitamin D that is administered. 1,25-dihydroxy- calcemia following parathyroidectomy in dogs with primary
vitamin D 3 (calcitriol) has the fastest onset of action and is hyperparathyroidism: 17 cases (2001-2009). J Am Vet Med Assoc.
preferred for treating hypoparathyroidism. The initial dosage 2012;241.
of calcitriol is 20 to 30 ng/kg/day. Dogs and cats should Dear JD, et al. Association of hypercalcemia before treatment with
ideally remain hospitalized until their serum calcium con- hypocalcemia after treatment in dogs with primary hyperpara-
thyroidism. J Vet Intern Med. 2017;31:349.
centration remains between 8 and 10 mg/dL without paren- Feldman EC, et al. Pretreatment clinical and laboratory findings in
teral support. Serum calcium concentrations should be dogs with primary hyperparathyroidism: 210 cases (1987-2004).
monitored weekly, and the vitamin D dose should be adjusted J Am Vet Med Assoc. 2005;227:756.
to maintain a serum calcium concentration of 8 to 10 mg/ Finch NC, et al. Parathyroid hormone concentration in geriatric
dL. The aim of therapy is to prevent hypocalcemic tetany— cats with various degrees of renal function. J Am Vet Med Assoc.
not to induce hypercalcemia. Serum calcium concentrations 2012;241:1326.
greater than 10 mg/dL are unnecessary to prevent tetany and Goldstein RE, et al. Inheritance, mode of inheritance, and candi-
increase the likelihood of unwanted hypercalcemia. date genes for primary hyperparathyroidism in Keeshonden. J
Once the serum calcium concentration has stabilized, Vet Intern Med. 2007;21:199.
attempts can be made to slowly taper the dose of oral calcium Graham KJ, et al. Intraoperative parathyroid hormone concentra-
and then vitamin D to the lowest dose that maintains the tion to confirm removal of hypersecretory parathyroid tissue and
serum calcium concentration at between 8 and 10 mg/dL. time to postoperative normocalcaemia in nine dogs with primary
hyperparathyroidism. Aust Vet J. 2012;90:203.
Vitamin D is critical for establishing and maintaining Guttin T, et al. Outcomes for dogs with primary hyperparathyroid-
a normal blood calcium concentration. Most dogs and ism following treatment with percutaneous ultrasound-guided
cats with primary hypoparathyroidism require permanent ethanol ablation of presumed functional parathyroid nodules: 27
vitamin D therapy. The calcium supplement often can be cases (2008-2011). J Am Vet Med Assoc. 2015;247.
gradually tapered over a period of 2 to 4 months and then Ham K, et al. Validation of a rapid parathyroid hormone assay
stopped once the animal’s serum calcium concentration is and measurement of parathyroid hormone in dogs with natu-
stable at between 8 and 10 mg/dL. Calcium in the diet is rally occurring primary hyperparathyroidism. Vet Surg. 2009;38:
often sufficient for meeting the calcium needs of the animal. 122.
Supplementing the diet with calcium-rich foods (e.g., dairy Milian M, Schiemdt CW. Preoperative factors associated with post-
products) helps ensure an adequate source of dietary calcium. operative hypocalcemia in dogs with primary hyperparathyroid-
Once the animal’s serum calcium concentration is stable and ism that underwent parathyroidectomy: 62 cases (2004-2009). J
Am Vet Med Assoc. 2013;242.
maintenance therapy has become established, reevaluation Rasor L, et al. Retrospective evaluation of three treatment methods
of the serum calcium concentration every 3 to 4 months is for primary hyperparathyroidism in dogs. J Am Anim Hosp
advisable. Assoc. 2007;43:70.
Sawyer ES, et al. Outcome of 19 dogs with parathyroid carcinoma
Prognosis
after surgical excision. Vet Comp Oncol. 2011;10:57.
The prognosis depends on the dedication of the client. The Primary Hypoparathyroidism
prognosis is excellent if proper therapy is instituted and Russell NJ, et al. Primary hypoparathyroidism in dogs: a retrospec-
timely reevaluations are performed. Proper management tive study of 17 cases. Aust Vet J. 2006;84:206.
requires close monitoring of the serum calcium concentra- Warland J, et al. Apparent resolution of canine primary hypopara-
tion. The more frequent the rechecks, the better the chance thyroidism with immunosuppressive treatment. J Vet Intern Med.
of preventing extremes in the concentration, and the better 2015;29:400.
the chance of a normal life expectancy.