I have mctd and had an extreme and life threatening case which started in 2005. Even though treated aggressively with pred for 6 months polymyositis hit me very hard, I lost 40 lbs of muscle in a week which gave me autoimmune hepatitis. It left me quadriplegic and unable to swallow anything. IVIG (5 day treatment) saved my life and aggressive PT/OT and speech therapies restored my function. Today I am healthy and lead an active life after years of therapy and exercise.
MCTD is very rare and very complicated but if your mother's doctors recommend IVIG I would not hesitate. It is often the only treatment that controls severe or resistant cases. Pred and azathioprine kept my immune system in check after IVIG and I have been in full remission since Jan 2006 and off all controlling meds for 2 years.
Most people in this forum are not familiar with IVIG or MCTD. Severe cases of MCTD are usually known for lupus or polymyositis symptoms (I had both) and sometimes others (scleroderma, RA or dermatomyositis).
MCTD (SLE Lupus, polymyositis, scleroderma). Diagnosed 2005. Kidney, liver, GI tract, dysphagia, raynauds, barretts esophagus, quadriplegic in 2005. Recovered and now active in downhill skiing, golf, hiking. Meds: amlodipine, benezapril, omeprazole, potassium, folic acid, vitamins, maxide.
Remain Optimistic and you can overcome.