HYPERCALCEMIA
Hypercalcemia denotes an elevated calcium level in the blood. Calcium is the most abundant mineral
in the body, and 99% of the body’s calcium is found within the bones and teeth. Calcium is essential
for helping the body perform various important functions, including:
A. Ensuring proper growth and maintenance of bones and teeth
B. Maintaining nerve and muscle function
C. Helping to regulate heart rate and rhythm
D. Facilitating appropriate blood clotting, hormone secretion, and enzymatic reactions
The body’s calcium level is strictly regulated by the coordinated actions of hormones, vitamins, the
kidneys, and the parathyroid glands. Calcium is routinely measure in blood tests, as extra calcium may
be toxic to many of the body’s tissues, particularly the kidneys, nervous system, and heart. Persistently
elevated calcium levels may result in kidney failure and/or heart failure.
There are many causes of hypercalcemia, and not all are due to disease. Insignificant causes include
collecting a blood sample from a pet that was not appropriately fasted. Pediatric patients also typically
have mild elevations in blood calcium due to bone growth. Laboratory error and false readings must
also be considered.
Unfortunately, significant illnesses may cause hypercalcemia, and the documentation of an elevated
calcium level may be your veterinarian’s first clue to the presence of an underlying disease. Common
disease associated with elevated blood calcium levels include:
1. Cancer
2. Hyperparathyroidism
3. Hypoadrenocorticism (Addison’s Disease)
4. Kidney Failure
5. Bone Diseases
6. Fungal and/or granulomatous infections
7. Vitamin D poisoning
The most common clinical signs associated with hypercalcemia include:
A. Increased thirst and frequency of urination with a poor appetite
B. Depression
C. Weakness / Trembling / Shaking
D. Vomiting
E. Diarrhea or constipation
Once your pet’s veterinarian has documented an elevated blood calcium level on a screening blood
test and confirmed the finding as a significant problem, further diagnostic investigation is needed to
determine the underlying illness. Recommended diagnostic tests may include additional blood tests,
hormone analyses, urine tests, radiographic and/or ultrasonographic examinations, bone marrow
analysis, and/or biopsies of abnormal tissues.
Treatment of hypercalcemia is directed at finding and treating the underlying disease. While awaiting
a confirmatory diagnosis of an animal’s primary problem, those with dangerously elevated calcium
levels need to be aggressively managed in a hospital environment with intravenous fluids and various
medications in an attempt to lower the blood calcium level to help prevent any toxic side effects.
The prognosis for animals with significant hypercalcemia ranges from excellent to poor depending
upon the nature of the underlying disease, the degree and duration of hypercalcemia, and the
presence/absence of kidney failure.