Reason for Fever

[sea4th]

A couple of days ago, I posted a tribute here to Lena, my mountain dog. It's all hindsight, & won't bring her back, but what would have caused her to have an extremely high temperature. This is a dog who was doing well with her malignant oral mass having been removed in January, a dog that was doing so well, that less than 24 hrs before her death, I bought 2 more months of Rimadyl for her. She happily ate at 10:00 p.m. Wednesday night & went to sleep with a full tummy. 12 hours later she was dead. Something went wrong in the early hours of Thursday a.m. At 7:00 a.m. I took her temperature. I thought there was something wrong with the thermometer and got a second one with the same reading---way over 106---just about blew the end off that thermometer. What on earth would make a dog's temperature spike so high in a relatively short time? Maybe I don't understand the dynamics of a fever, but I really am wondering.

 

I'll be talking to my vet again on Monday.

 

TIA

 

Vicki

[AK dog doc]

Hi Vicki

There are lots of causes of elevated body temp, but some of the ones that might be relevant here would include infection (either viral or bacterial); inflammation (many reasons); drugs/toxins (though probably not the Rimadyl, since that tends to lower the temp, not raise it. But never say never in medicine); and tumors. Since she'd had a previous malignancy, there's the possiblity of metastatic lesions elsewhere in her body (including, possibly, the brain, where the thermoregulation centers are). I'll point out that tumors do NOT have to be in the brain in order to make their victims spike fevers.

 

There could be other reasons for the high temp, such as heat exposure (such as being in a car on a hot day), excessive activity or seizures, but I feel sure you'd have mentioned these if they occurred (and I can't picture you leaving your dog in an enclosed car on a hot day, in any case). There's also something called "fever of unknown origin", but the definition of that says to diagnose that you have to have a fever that occurs persistently for 2 weeks in a hospital setting. Don't ask me WHY that's the definition, but there you go.

 

In a case like this, I'd be thinking in terms of the tumor and/or possibly some infection and/or inflammation. In any case, 106 is pretty worrisome, particularly if she was getting her Rimadyl and that didn't bring it down. It might be that she'd reached that threshold where things are about to go south in a big way and that was one of her symptoms thereof.

 

Naturally your vet may have more concrete ideas about this than I do, since s/he was seeing Lena all along, so if you get different info there than I mentioned, I'd go with their assessment over mine.

[sea4th]

she'd reached that threshold where things are about to go south in a big way and that was one of her symptoms thereof.

AK Dog Doc,

 

I agree with you. Also, what you said about the portion of the brain that regulates temperature---Lena's oral tumor was on the roof of her mouth. It was a really fast growing tumor, but it came off with laser surgery very easily & had a small base, so it kind of resembled a mushroom. Although it was a rapid growing tumor, never saw any indications that it was coming back, not at least from the side I could see. Perhaps it actually did drill into her brain?--affecting the temperature regulating portion of the brain---although I would have expected seizures with that scenario.

 

I realize all this is speculation and in hindsight, there was nothing I could have done anyway, and I truly am grateful that she went as quickly as she did with no obvious pain---but I'm still curious. Maybe it's a way of my coming to grips with her loss.

 

Anyway, I really do appreciate your feedback.

 

Vicki

[AK dog doc]

Tumors don't have to travel by direct invasion, though some do - they can also do what's called hematogenous spread, which means they travel via the blood (or lymph) vessels and set up housekeeping in distant sites. The lungs, spleen and liver are big sites for this, because of the high circulation these organs get, but there's more to deciding where you're going to metastesize to than just blood supply - the kindeys also get a huge blood supply, but they're not as frequently colonized as other organs are, for example. It could be that the tumor stalk was more deeply rooted than was known, it could be that there was hematogenous spread, or it could be part of what's called a "paraneoplastic syndrome", which is a situation where the tumor - sometimes even quite a small tumor - releases mediators that effect changes elsewhere in the body. An example of this is in lymphosarcoma, in which the tumor sometimes releases a hormone-like substance which mimics the body's normal hormones and causes the dog's serum calcium to go up extremely high, high enough to cause kidney failure in short order unless it's treated. In fact, sometimes it's the sypmtoms of the hypercalcemia that trigger the owner to bring the dog in - not the presence of any other tumor signs - and thence the high calcium which triggers US to go on a tumor hunt. So if there were a paraneoplastic syndrome, it could trigger abnormal responses in the body from sites far distant from the brain, but ACTING on the brain from that distance - or else acting on other tissues to create a secondary problem which then drove the temp up as a tertiary problem. This is, of cours, all presupposing that the tumor was in fact the culprit. Does that make sense? It's kind of a confusing explanation.

[sea4th]

Hi AK Dog Doc,

 

Talked to my vet---of course, it's all educated guesses & speculation & she said even if we did a necropsy, one still might never know, but anyway, she said that judging by the symptoms I described, she said it might be something like peritonitis, where the bowel is perforated (tumor rupturing?) and the contents seep into the abdominal cavity. She mentioned a few other possibilities, as did you, but I really questioned her on this one. We don't know if she was riddled with tumors throughout. I would venture to say yes, she was. So this really made sense to me. My vet said that under those circumstances they do go quickly.

 

Just thought I'd share my conversation with the vet & want to again, thank you a lot for your input.

 

I'm just grateful Lena went as quickly as she did with very little apparent suffering.

 

And I think I learned something in the process.

 

Vicki

[AK dog doc]

Glad to have been of whatever help I was, though sorry it's on such a sad subject.