rewrite this title Why Are Cats Such a Medical Black Box?

Maybe that was a true reflection of reality. Our dogs regularly romped through Prospect Park in Brooklyn, swapped germs with playmates and scarfed down rogue chicken bones, while our cats lived cosseted, indoor lives.

Now I suspect that we may have missed signs of illness in our cats. I had worried that we were overreacting when we took Olive to the vet for seeming maybe, slightly, sort of not herself. In fact, she was critically ill.

Indeed, cats are talented at masking their symptoms, which may also present differently from those in dogs, experts told me. Arthritic dogs often develop noticeable limps, which are easily spotted on walks, while many arthritic cats show no obvious signs of lameness, Dr. Perry said. They might just jump onto the couch less often or seem crankier when being handled.

“Given that cats are sleeping so many hours a day, and owners are generally only around them for a few of those hours, it’s much easier to not realize that your cat is gradually changing over time,” Dr. Perry said.

In retrospect, it seemed likely that Olive had been quietly declining for weeks.

Eventually, vets concluded that her immune system was destroying her red blood cells. But they couldn’t say what had triggered it or find a medication that helped. Finally, as something of a last resort, an internist suggested that we could consider removing Olive’s enormous spleen, which was probably where her red blood cells were being destroyed.

I emailed another veterinarian for a second opinion. “Splenectomy is not the worst option,” she wrote back, noting that it was an established treatment for human patients with similar conditions. “We just don’t have data in vet med,” she added, “especially in cats.”

Getting curious about cats