I am sorry to hear that your pup is again not eating, and having trouble standing and walking.
Is her head tilted to the right or left?
When she tries to walk is she circling or leaning to one side or walking very slowly with a wide stance and then leaning and falling over?
Does she have rhythmic back and forth or circular eye movement?
(like this dog : http://www.youtube.com/watch?v=NaB7OJRLVQ4 ).
If the answer to these questions is yes then she may have vestibular disease. Vestibular disease is a malfunction of the balance system, either a problem in the inner ear itself or in the nerves that take information to the brain or in the brain itself. Episodes often come on suddenly.
With vestibular disease she can get very dizzy and as such have trouble with coordinated movement. They will often fall or lean to one side.
It makes sense that she was initially vomiting a lot before she stopped eating because she was likely very, very dizzy.
There can be several causes of vestibular disease. They range from very benign causes such as idiopathic (meaning we don't know the cause but they resolve on their own with supportive care) to middle ear infections or polyps, brain infections (bacterial, fungal or viral) or even a primary brain lesion such as a blood clot, bleeding or a tumor.
If we cannot identify a cause then we will often treat the patient symptomatically (anti-nausea drugs, anti-inflammatories and possibly antibiotics if an ear infection is a concern) as most dogs do get better with supportive care. It sounds like is what was done for your girl, and she initially responded but has now regressed.
Her prognosis if this is caused by a lesion outside the brain is very good in most cases.
We may check bloodwork to make sure organ failure or low thyroid hormone are not the cause of her symptoms. Since she isn't improving then blood tests should be done to make sure all is well internally. In dogs that have signs of an inner ear infection we may take radiographs of the skull to check the bones of the inner ear for signs of a mass, or thickening or fluid in the ear. Some cases require that we make a hole in the ear drum to drain the infection and culture the fluids to make sure we are treating the infection with the right medications. In some cases surgery is needed to debride the infection or in some cases we need to perform an ear ablation to remove the infection or a tumor.
Is she still taking any medications to help with her being off balance?
At home you can give Gravol also known as Dramamine (dimenhydranate) to control nausea, which is also used for carsickness. The dose is 4mg to 8mg per pound of body weight every 8 hours. Side effects are mild sleepiness and dry mouth.
Or you can try Benadryl (diphenhydramine only, do not use products with acetaminophen or decongestants as they are toxic for dogs) at 1mg to 2mg per pound of body weight orally every 8 hours. Side effects are sedation and dry mouth as well.
To stimulate her appetite start a bland diet of 1/3 boiled, lean hamburger (or boiled, white skinless chicken), all fats and juices drained off mixed with 2/3 boiled, plain white rice. Add warmed low salt chicken or beef broth to get additional fluids into her and make the food more palatable. Feed several small meals a day.
You may need to hand feed her and offer her water or ice cubes to lick as she may have difficulty negotiating eating and drinking on her own.
If she still won't eat even after medication to decrease her dizziness and offering a bland diet then to help with nausea at home you can give either:
1) Pepcid ac (famotidine) at a dose of one 10mg tablet per 20 to 40 pounds of body weight every 12 hours
2) Prilosec (omeprazole) at a dose of one half of a 20mg tablet per 20 to 40 pounds of body weight every 24 hours
These are acid reducers and should help her feel a little less nauseous. They are quite safe and can be used for several days if necessary.
If she starts vomiting or refuses to eat for a couple days she may need hospitalization for supportive care, fluids and injectable medication for nausea.
In some cases when the patient worsens she may need further diagnostics to try and identify the cause. Serious central nervous system (the brain) causes are more likely and thus prognosis is much more guarded.
Things such as an MRI or spinal tap are indicated at that point.
If she is not improving a referral to a neurologist is best as they can perform this advanced testing.
Please see this link if you would like to read more about vestibular disease:
Please let me know if you have any further questions