Hello, thanks for your question today! I am Dr. Drew, and I am a licensed veterinarian. I'll be happy to help you in any way I can.
I'd be curious to know which antibiotics were used,
as there are some types of antibiotics that are more effective against tick-borne illnesses.
Doxycycline and Minocycline are the preferred choice for treatment of most tick-borne infections.
Though not very common, cancer is something we do need to keep in mind here.
I've seen several young Golden Retrievers with Lymphoma, a type of cancer that can cause enlargement of the internal organs, fever, and a failure to respond to antibiotics.
So if the problem has not responded to the correct drugs,
then I'd have to suggest further internal investigation, perhaps even including biopsies of the liver, to determine what is going on at the microscopic level.
She was on tetracycline for tick fever till three days ago. Now the vet has changed to a more generic antibiotic for three days. She will be back on tetracycline for another 2 weeks
Her reports are attached.