Strokes are extremely rare in dogs
Geriatric dogs can develop a condition known as Vestibular Disease. The dog will exhibit loss of balance resulting in it unable to stand, sometimes head tilting, eye movement from side to side, and disorientation.
Very little is understood about this neurological disease. Most dogs will spontaneously recover anywhere from 3 days to 3 weeks in time. Sometimes Prednisone aids in recovery. Tranquilizers should not be used as it makes a disorientated dog more disorientated. Once the dog recovers it usually will not have another attack, although some do have repeated occurances.
If the dog hasn't recovered in 3 weeks, then you have to consider getting some diagnostics run. Examples include: A blood panel to check for hypoglycemia, an MRI to check for possible brain tumors, or checking for an inner ear infection.
Check with the Vet on the Prednisone, and give puppy more time. Hopefully it's Vestibular Disease and puppy will spontaneously recover.
Prednisone can do strange things
Nothing like constipation and gas. Poor thing. :D Give it time, puppy will be ok mighty fine.