Explain avascular necrosis of the femoral head

Can some one explain the physiology of avascular necrosis as it relates to the femoral head?  I have been on steroids for three years now to keep my blood pressure from bottoming out, so I stop passing out.  The steroid use is the cause, what is the fix?  If I stop the steroids will it resolve?  Until I see the surgeon are there steps I can take to prevent the failure of the femoral head?  Any way to prevent further damage?  Any exercises I can do to strengthen surrounding muscles without compromising the integrity of the femoral head?  If this is happening in my hip, can it be happening elsewhere in my body?  At Easter I boiled and dried 100 eggs for church.  Then I dyed and dried them.  That night I suffered excruciating pain in both wrists, to the point I couldn't sleep.  I have been having serious problems ever since.  Numbness, tingling and horrible pain.  Wearing wrist braces helps.  I assumed it was my carpal tunnel rearing it's ugly head.  Could it possibly be avascular necrosis there too?  In case you can't tell, I'm a little freaked out.  I had the CAT scan because of enlarged lymph nodes and calsification of the pancreas due to lupus.  They didn't see any of that on this  follow up CT scan.  I was prepared for the BIG C and was blind sided by this diagnosis.  Thank you in advance for your input.