Getting to the bottom of your pet's unexplained fever - Dr. Marty Becker

Getting to the bottom of your pet’s unexplained fever

Tuesday, Apr 19th, 2016 | By Dr. Marty Becker

Sleepy beagle puppy lying on the table

Has your pet ever started running a fever for reasons no one could figure out? That’s what happened to a reader. Here’s her story and my advice:

Q: My dog had her teeth cleaned, and all went well with a couple of extractions. A week or so later, she wouldn’t eat, and when we took her to the vet, she had a 104-degree fever. We tried a couple of different antibiotics, which didn’t reduce the fever, so we were referred to a specialty hospital. They tested for everything, and she wasn’t getting better. The vets kept her overnight and gave her fluids and super antibiotics, but she would not consistently eat and every test came back negative.

Long story short — and $10,000 later — my vet took an X-ray of her mouth and discovered an abscess in the jaw. He removed the tooth, cleaned out the abscess, gave her antibiotics and away she went. Why is it so hard to find the cause of a fever like this?

A: What an ordeal! I really feel for you. I can tell you that it’s a real diagnostic puzzle when fever is the only significant sign on examination. My colleague Kenneth R. Harkin, an internal medicine specialist at Kansas State University College of Veterinary Medicine, spoke on this subject in January at the North American Veterinary Conference in Orlando, Florida. He says that figuring out the cause of a fever of unknown origin — also called a cryptic fever — becomes challenging when routine diagnostic tests don’t pinpoint the problem.

As you discovered, the cost of testing (and hospitalization) can skyrocket as veterinarians seek other answers. Inflammation is the most common cause of fevers, Dr. Harkin says. Among the many possible inflammatory or infectious diseases that could cause fever are acute pancreatitis, pyelonephritis, lupus, immune-mediated polyarthritis and leptospirosis. Dogs with a recently discovered heart murmur may have bacterial endocarditis. Certain cancers can cause fever as well, including lymphoma, leukemia and liver cancer. All of these can be easily missed because abnormalities in the lab work can be subtle.

I’m glad your dog’s fever was successfully resolved.

Read more, including how to protect your dogs and cats from heartworm, in this week’s Pet Connection!