Hyperparathyroidism means too much parathyroid hormone (PTH). In primary hyperparathyroidism (PHPT) a parathyroid nodule secretes PTH on its own and the dog becomes hypercalcemic. In the secondary forms, kidney disease or a poor diet lowers ionized calcium and the glands respond appropriately, so calcium is normal or low. For the exam, the skill is reading calcium, phosphorus, PTH and PTHrP together to tell PHPT from cancer, vitamin D toxicosis and kidney disease.
Key facts
Hyperparathyroidism at a glance- Species / system: Dog; parathyroid glands, calcium and phosphorus metabolism.
- Primary HPT: autonomous PTH secretion, usually from a single parathyroid adenoma; less often hyperplasia or carcinoma. Older dogs (mean 11 years); Keeshonds carry an autosomal dominant form.
- Classic presentation: an older dog that looks well, with hypercalcemia found on routine bloodwork or during a workup for calcium-containing uroliths or urinary tract infection.
- Key lab pattern: high ionized calcium, low or low-normal phosphorus, normal kidney values, and a PTH that is mid-normal or high instead of suppressed.
- Secondary HPT: renal (chronic kidney disease, high phosphorus) or nutritional (growing dogs on all-meat diets). Severe cases cause fibrous osteodystrophy ("rubber jaw").
- Not zoonotic or reportable.
What's inside
12 sections in the full guide- Key facts
- How the NAVLE tests this
- Cause and pathophysiology
- Clinical signs
- Diagnosis
- Differential diagnoses
- Treatment and management
- Prevention
- Prognosis
- Quick review
- Test yourself
- References
The full guide also has 5 tables, 3 figures, 3 self-test questions and 27 references, available to NAVLE members.
Read the full study guide
The full guide is part of every NAVLE plan, with diagnosis and treatment tables, figures, a quick review and self-test questions. Start a free trial to try the question bank, or log in if you are already a member.