Prolonged Fever In My Dog

[Housefly]

My dog came down with signs of fever and lethargy about a week ago. We took her to the vet and went through the suggested series of tests to diagnose the underlying cause, but all of her tests have come back negative. I'm desperate to figure out what is making her sick!

A little recent history: She had a tick on her neck late this past summer, but the tick was tested for Lyme and came back negative. About 4-5 weeks ago we noticed that she was licking her wrists quite a bit, (a habit she'd had on and off) and then a small elevated nodule appeared on the inside of her wrist. We were told it was likely a granuloma from too much licking and we treated it with cream and it disappeared after about a week.

When the fever showed up last week, the vet did blood work which showed that her red blood cell count is diminishing slightly, and she is slightly anemic. They did blood tests for Lyme and Heartworm (4DX test) which came back negative. X-Rays came back clean. She had an ultrasound which indicated slight abnormality and swelling of the liver and spleen and some suspicious nodules on the spleen. They did biopsies of liver, kidneys and spleen and they came back negative for cancer. We just had her bone marrow and spinal fluid sampled and those tests came back non-cancerous. Multiple joint taps also came back clean. She's been on several antibiotics over the course of our investigations in an attempt to treat the most likely infections that might cause the symptoms, but her fever has still not lowered significantly from its average 40 degrees celsius. Metacam has been used to try to reduce her fever but has not worked, so she's been taken off of it. I can't remember the names of the specific antibiotics now, but Clavaseptin was one she's been on I think and Doxycycline another. We've sent off blood samples for Leptospirosis and Bartonella...
We're running out of tests to do (not to mention money) and we're just about at our wits end. If anyone has any suggestions based on past experience as to what this might be, I'd really appreciate your input.

Thanks!!

[ginger899]

I just read an update on housefly's post on the Ask A Vet Expert Forum. It's good news the dog responded to treatment with Prednisone.
That doesn't mean it would be suitable for your dog....I don't know. The best thing to do is take a look at that post (there's a link to it right underneath this one under "related discussions")
You could read this, and then have a word with your vet?

[farleythedog]

I have an 8 year old bearded collie that has had a temperature of 40.5 for about 4 weeks now. We had blood tests done for Lyme disease and may other tick related diseases plus kidney and liver. We put him on doxicycline for lyme as we waited for the test results. Turns out everything is normal, no lyme, and the pills made no difference to the fever. We tried cephalexin to no avail, and our last attempt at antibiotics is zeniguin. I thought because he has become rather lame, his legs give out occasionally, that it would have been lyme.  He eats at least, half of his normal amount. What has happened to your dog? I see by the date it was a while ago, today is June 25 2010. Anyone have any advice?

[lindapalm]

Also, I read on another site about four other tick diseases, Ehrlichia, Rocky Mountain Spotted fever, Anaplasmosis and Babsesia.  Has your dog been tested for these?  Good Luck.

[lindapalm]

I know years ago Lyme tests could come back false negative, have they improved them since then, or could that still be possible with your dog?