Idiopathic Hypercalcemia in Cats: A Guide

Nearly every cat owner can attest that their furry friend is an important and beloved member of the family, and when their pet isn’t feeling well, hearing distressing news from a veterinarian causes anxiety. While it’s important to listen to everything the vet has to say during and after a visit, conducting additional research as a pet parent can sometimes help to ease one’s nerves and provide some clarity. 

A diagnosis of idiopathic hypercalcemia in cats can sound concerning for any pet owner. However, understanding it on a medical level is critical so you can provide your cat with the best care possible during this difficult time. Essentially, the term translates to a spontaneous (non-event-related) buildup of calcium in the affected feline’s bloodstream. Rather than having a clear symptom that signals the issue, this problem is usually discovered by routine blood work during a vet visit. In fact, this potential discovery is one of the many reasons it’s important to take cats in for regular health checkups, at least once a year. 

What Causes Idiopathic Hypercalcemia?

When a beloved pet comes down with a health issue, it’s natural – although typically misplaced – for a pet parent to feel guilty. In the case of idiopathic hypercalcemia, though, it’s literally impossible for owners to have any part in their cat’s ailment: it’s completely spontaneous. 

Idiopathic hypercalcemia is not caused by:

  • Diet or treats
  • Level of activity
  • Grooming (or lack thereof)
  • Fleas or canine parasites
  • Other pets
  • Stressful environment

So for fur-baby folks who’ve been feeling like there was more that could have been done to prevent the diagnosis, relax: the most important thing right now is to focus on professional treatment and healing for the afflicted cat. 

Is Feline Idiopathic Hypercalcemia Contagious?

Idiopathic Hypercalcemia in Cats: A Guide | Canna-PetUnlike certain cat health concerns like feline distemper, cat fleas, or skin conditions, hypercalcemia isn’t contagious. For owners who have more than one cat in the home and are worried that co-sleeping, mutual grooming, or sharing food and water bowls can transmit it, rest assured it’s not going to spread to other household pets or humans. In fact, as a cat diagnosed with this illness deals with treatment and medication, he may actually find comfort in the presence of his feline roommate. Alternately, however, if he regularly has disagreements or fights with other animals in the residence, it may be wise to isolate him as he heals. If he is given medication for his condition, this can also be a useful step: if his food and water is isolated, it can be medicated for easier dosing.

It May Signal Or Aggravate Other Health Issues

Cat owners typically hear about this condition through their veterinarian, post-bloodwork results. While most vets will preemptively test for concurrent ailments, idiopathic hypercalcemia in cats is a relatively new phenomenon, with an exponential growth in cases over the last twenty years. For that reason, it may be beneficial to discuss the possibility of feline chronic kidney disease or certain cancer diagnoses as well with the vet clinic. 

While idiopathic issues are, by definition, not linked to a cause, there is a correlation between these more serious feline health problems and the presence of hypercalcemia. Additionally, due to the nature of hypercalcemia, illnesses caused by an abundance of calcium such as kidney stones (“uroliths”) can be exacerbated by the presence of additional calcium.

Treatment for Feline Idiopathic Hypercalcemia

While still a serious condition, feline hypercalcemia is generally considered to have a slow progression, and therefore a promising window of treatment. Thankfully, the first line of treatment is generally the easiest, at least in terms of administering medication. A specialized diet is recommended for about one to two months, one high in protein but low in carbohydrates. The veterinarian may recommend a brand sold in their office or to a store brand that will meet the cat’s adjusted dietary needs. After the diet has had time to work, additional blood work will likely be examined to test calcium levels and judge if enough progress has been made to continue.

Idiopathic Hypercalcemia in Cats: A Guide | Canna-PetIf the results still point to an abundance of unwanted calcium, the vet may recommend medication to inhibit the cat’s reabsorption of shed calcium and prevent the cycle from continuing. As any pet owner that’s had to “pill” a cat can attest, this can be a difficult endeavor. To minimize trauma to one’s cat, try a two-person approach, with one individual swaddling the cat in a towel to prevent scratches, and the other placing the pill in the cat’s mouth and gently massaging the throat with the back of a finger to induce swallowing. Experts also recommend placing a small smear of butter on the top of the cat’s nose afterwards to induce licking and swallowing. 

Maintaining Your Cat’s Health

Once diagnosed with idiopathic hypercalcemia, the affected cat will always have it on his health radar, which means pet parents will need to be vigilant as his caregivers. Even if his results go from worrying to promising with diet alone, he’ll need regular checkups to make sure it isn’t flaring up. Therefore, continuing a dialogue and routine follow-ups with a trusted vet about the cat’s condition and overall health is very important – be sure to ask for their recommendations on an appointment and/or testing schedule to ensure his quality of life and well-being. 



de Papp, Erika, DVM, DACVIM. “Idiopathic Hypercalcemia.” (MSCPA Angell), (no publish date), Accessed June 23, 2019.

“Feline Idiopathic Hypercalcemia: The Rise of IHC.” Feline, (no publish date), Accessed June 23, 2019.

“Pet Education: Feline Hypercalcemia.” Pet (Pet Assure Corp), (no publish date), Accessed June 23, 2019.

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