Pred will make your blood sugars go sky high. They can also make a pre-existing condition worse.

Mine started in my right eye, then couple months later it hit all my muscles.
I started on 180mg of mestinon. Then added a high dose of Pred. that shot my blood sugars up but it was a 3 month treatment but it put me in the hospital for 5 days with Diverticulitis. No more Pred for me. I have had 3 IVIG treatments. I am currently taking 60mg of Mestinon 3x a day and 1 180mg time release at night. I also take 200mg of Imuran a day. I have lost 35 pounds but I'm finally stable at 145lbs. My double vision has cleared up about 80% still have a little looking down or far left. I went 11 months without driving but I can drive now but have slowed down a lot.
Mike