Hello, I'm Dr Gary. I've been practicing veterinary medicine since 2007. I look forward to helping with your questions/ concerns.
This is tough to know what is causing the fever and low white count. If the white count is just slightly low (in the 2-5,000 range), then it's probably just due to consumption of white cells at the site of the infection. If it's < 2,000, then I would worry about something affecting the actual bone
If there is an infection somewhere, then I usually do x-rays to try to find it. It could be pneumonia, an abscess in the abdomen (liver, spleen), a kidney infection, a bladder infection, a tooth root infection, ect. Many times we never find the source of infection. In those dogs, I'll often have them on a combination of Clavamox
. This is a nice broad spectrum antibiotic combination.
If they think it's in the bone marrow, then I would do a bone marrow biopsy. In that case, you're trying to determine if it's an infection or an auto-immune disease. If auto-immune, then he'll need to go on steroids (Prednisone).
I know it's not an easy answer, but these FUO (fever of unknown origin) dogs can be tough to diagnose and treat.
Let me know if you have any other questions.