What is the most common cause of hypercalcemia in dogs? Get Your Pet Thinking

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How are levels of calcium controlled in the healthy animal?

Calcium levels are controlled by a pair of parathyroid glands. The two tiny glands are embedded in the thyroid gland, which sits just below the larynx or “voice box” overlying the windpipe. The parathyroid glands are responsible for monitoring the calcium level in the blood. When calcium levels are too low, the glands release a hormone called parathyroid hormone (PTH), which acts to return calcium levels to normal.

Incidence of Calcium Disturbances in Dogs

For dogs, 44,366 records were identified across the 9.5-year period. After removal of subsequent or follow-up analyses, the initial analyses from 15,277 individuals remained. Of these, 1,643 electrolyte profiles documented hypercalcemia. After removal of two profiles from dogs that were dead-on-arrival there were 1,641 profiles with hypercalcemia, corresponding to an incidence of canine hypercalcemia of 10.7% (1,641/15,277). Hypocalcemia was documented in 1,468 profiles. After removal of one profile from a miscoded Fennec fox there were 1,467 profiles with hypocalcemia, corresponding to an incidence of canine hypocalcemia of 9.6% (1,467/15,277).

Differential diagnoses include:

  • Hyperparathyroidism
  • Hypoadrenocorticism/Addisons disease
  • Chronic kidney disease
  • Hypervitaminosis D (Vitamin D toxicosis): Cholecalciferol rodenticide toxicosis, plant intoxication (e.g.: blooming jasmine), excessive dietary supplementation, ingestion of human medication containing calcitriol (e.g.: psoriasis cream) and over-supplementation for hypoparathyroidism are causes reported for hypercalcaemia
  • Idiopathic (Cats)
  • Osteolytic disease
  • Neoplasia – Lymphoma, apocrine gland adenocarcinoma of the anal sac and multiple myeloma are common paraneoplastic causes of hypercalcaemia. Other tumours such as squamous cell carcinoma, lung carcinoma, malignant melanoma, osteosarcoma, metastatic bone tumours and mammary carcinoma are less common causes of hypercalcaemia
  • Granulomatous disease
  • Spurious – lab error or hyperproteinaemia are causes for increased calcium levels
  • Young age – total hypercalcaemia can be normal in young dogs, however ionised calcium levels should be within normal limits

    • History should be obtained including duration of clinical signs, any changes to drinking, energy levels or behaviour and potential access to toxins, medication or diet for possible hypervitaminosis D. A thorough physical examination is very important to carefully assess peripheral lymph nodes and a rectal examination should also be performed.

    Stacey A. Newton – Hypercalcaemia In Dogs and Cats: An Overview | Nationwide Laboratories | PREVIEW