Hello and thanks for researching this important question!
Guinea pigs can have neurologic signs (including a "head tilt" that is accompanied by vertigo) from a variety of conditions such as Mange Mite infestation and inner ear infection.
I am including a number of links that you can use to try to narrow down some of these symptoms, and find a veterinarian who is qualified to help you:
http://www.guinealynx.com/hairloss.html
http://www.cavyinfo.com/html/vet.htm
http://www.aracnet.com/cgi-usr/seagull/vetfinder.cgi
http://cavyspirit.com/vets.htm
In the meantime, please make sure to continue offering baby foods (fruits and veggies--the fruit types may be more enticing)...find a pediatric vitamin C supplement and give 25 mg daily to increase the immune health of this dear pet. You can melt her regular pellet food in water or fruit juice (no-sugar-added types) to make it easier to feed using a dropper.
Feed very small amount throughout the day...the dizziness that can accompany this type of problem makes it hard to swallow and feel comfortable while eating.
If you need additional support at this time, please click "Reply".
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