Hypercalcemia is an abnormally high level of calcium in the blood.

Normally, calcium is stored in the bones and controlled by the parathyroid glands in the neck. With hypercalcemia, these glands send hormones to the bones to release excess calcium.

The kidneys get rid of the extra calcium through the urine; however, when there is too much, the kidneys cannot get rid of it. This leads to kidney damage and failure.

The calcium deposits itself in the soft tissues, causing pain and inflammation. Additionally, the bones become weak and easily breakable.

CAUSES:

While some cases are idiopathic (no known cause), other cases have an underlying disease, such as:

  • Kidney failure
  • Addison’s disease (failure of the adrenal gland)
  • Parathyroid gland tumor
  • Cancer
  • Dehydration
  • Toxins (such as an overdose of Vitamin D)

SIGNS:

  • Lethargy
  • Loss of appetite and weight loss
  • Increased thirst and urination
  • Constipation or diarrhea
  • Vomiting, dehydration

If you notice any of the above symptoms, go to your veterinarian right away. Too much calcium can lead to kidney damage.

DIAGNOSIS:

To properly diagnose your cat with hypercalcemia, your veterinarian may perform the following:

  • Blood tests: to check for high calcium
  • Repeat blood test: after your cat has fasted to confirm high calcium

If the tests confirm hypercalcemia, your veterinarian will perform other tests to look for an underlying cause:

  • Additional blood and urine tests: to check kidneys, adrenal glands, and parathyroid glands
  • X-rays: to check for cancer
  • Ultrasound: of the parathyroid glands
  • Biopsies

TREATMENT:

Most veterinarians will recommend the following treatments for cats with hypercalcemia:

  • IV fluid therapy: to treat dehydration and to keep blood flowing to damaged kidneys
  • Diuretics to help excretion of calcium

Additional treatment will focus on treating the underlying cause.

Some cases require surgery to remove the parathyroid gland.

PREVENTION:

  • Provide easy access to drinking water to avoid dehydration
  • Avoid exposure to toxins containing Vitamin D, such as rat poison

PROGNOSIS:

Adult cats have a better prognosis than kittens, and with quick treatment, the prognosis improves. Organ damage may be life-long.