Undiff. Connec. Tissue disease. Tx: plaquenil&prednis. Bursts. Most symptoms resolved now but still get days of crazy dizziness. Prednis resolves it. Causes?

Not clear. It's unclear whether this is related to the connective tissue disease or something else and possible causes could be related today inner ear, or it could be a central nervous system problem.
Several disconects! Cerebritis is an extraordinary feature of mctd. Your improveemt with Prednisone could be the result of sinus or inner ear problems. These dxs should not be discarded. Also, is your blood pressure low? Taking a "burst" of pred may increase it. Talk to your doctor.