Just a warning, if you suspect Lupus or any auto-immune disorder, run, don't walk to a rheumatologist!!! In 1997 I noticed I could no longer throw a basketball as high as a hoop. Far too many visits to internal med, then ortho, then neuros when I could no longer walk. Some "I don't knows" (I respect them) some wrong dx's, some outright dangerously wrong dx's. Finally in 2010 I got to a rheumy who diagnosed me in under 5 minutes (polymyositis).
Immune system attacking muscles.
By the time you notice weakness with poly, (1997, remember?) you've already lost 50% muscle mass! I continued losing muscle till 2010, 13 years!, and now at 61 I wont be growing much new muscle. I'm permanently disabled, live on Vicodin, Humira, methotrexate, and sometimes roids.
The immune system isn't studied in depth in medical school. It's left for those that go on to a rheumatology internship. Despite elevated cpk and ANA, I tested neg for lupus, then the docs would give up. My rheumy diagnosed by history and brief physical exam alone!
I hope this helps others avoid similar medical mis adventures and suffering.