My dog has an infection, any advice?

[Laurienna]

2 days ago Piper our mastiff/lab mix didn't want to use one of her rear leg. It has happened before and usually a few hours later she is using her leg like nothing happened. This time though it seemed worse and the next day we took her to the vet. It turns out that she had a really high fever (104.5) also. They took x-rays that looked normal except for fluid at the knee. The vet could not get enough fluid to have a culture but she did not see any obvious signs of bacteria under the microscope. She took blood and urine samples as well and we should have the results for these later today. Piper wanted out at 4 am and she peed but she is not using her leg at all and doesn't want to move around at all either. She does not uncurl her toes on that leg even lying down. We started on an antibiotic last night and this morning her fever is down a bit (102.6). She looks very much in pain but the vet did not give us anything for that.
Have you ever heard of anything like that before? Is there anything we can do to help her feel better? It's just so weird because there is no sign of injury on her at all...how come she would have an infection?
We adore that dog and would do anything for her but I'm not sure of what else to do...supplements, yogurt maybe because of the antibiotics?

[Oubliette8]

Is Lyme disease an issue in your area or any place your dog has visited in the past 6 months or so? It can cause fever and sudden lameness. I believe for diagnosis the vet needs to take a blood sample for testing. Even vaccinated dogs can sometimes catch the disease. If your dog has been vaccinated, you may need to make sure your vet uses the correct test- vaccinated dogs will automatically come up positive for some tests, but there are tests that can detect the disease in vaccinated dogs. The treatment for Lyme disease is the antibiotic doxycycline.

Clean xrays are a good sign, most bone cancers would show up on an xray from my understanding. One thing I did come across was Coccidiodomycosis, which is a fungal infection that can sometimes cause lameness and bone infection like you describe. It occurs in the southwest and has been reported in Sacramento. I would probably start with a lyme disease test.

To help your pup- first, ask the vet about pain relief. Mine routinely gives Rimadyl for pain relief short term. You can also buy doggy aspirin at the pet store. I would ask the vet first though, there may be a reason he has NOT prescribed something- it might interfere with the antibiotics, he might not want the dog walking on the leg before its ready etc.

To help- yogurt won't hurt, and the dog would probably enjoy it. You could also but a warm compress on the leg if you feel it might help. It cant hurt.

One more thought- how old is the dog? Panosteitis can sometime occur with a fever. It is common in large or giant breeds. It ussually only occurs in dogs under 2 years old though.

I hope you figure it out and he feels better soon!

[Laurienna]

Thank you Oubliette8. Things took a turn for the worse yesterday. Piper started to cough and refused to move, we took her back to the vet and she had a temp of 106.5. The vet feared that she was getting pneumonia and generally getting worse. So we took her to a 24h care place so that she could receive antibiotics directly into the blood stream. They took xrays of her chest but they don't think it's pneumonia, ultrasound of major organs all showed that everything looks normal. They are doing more cultures and blood testing notably for Lyme but it's very unlikely to be it. I called this morning but the doctors are still doing the rounds and are going to call me back. I'll mention the coccidiodomycosis, it looks like a possibility. Our vet didn't hide that her prognosis was really poor and we are crushed. And spending $4000.
I don't get it, she has never had a problem before and she is almost 5 so panosteitis seems unliquely even though i wish that were it.
Thank you very much for your suggestions.

[Oubliette8]

I'm so sorry to hear she is worse. I hope they figure it out and things start looking up. I'll keep her in my thoughts.