What are the risks of steriod treatment for giant cell arteritis?

The Bottom Line: The evidence supporting the use of steroid-sparing immunomodulatory agents such as methotrexate for long-term management remains debated.  Despite treatment with high-dose corticosteroids,
bilateral vision loss, or worsening of unilateral vision loss may sometimes occur.  See Table 3, p. 16, for fuller details.

Reference: J. Alexander Fraser, MD et al.  The Treatment of Giant Cell Arteritis.  Rev Neurol Dis. 2008 Summer; 5(3): 140–152.

Summary: The treatment of GCA must be adjusted to each case, and recommendations vary widely in the literature.  Although there is no randomized controlled clinical trial specifically evaluating GCA patients with ocular and neurological complications, we recommend that GCA patients with acute visual loss or brain ischemia be admitted to the hospital for high-dose intravenous methyl-prednisolone, close monitoring, and prevention of steroid-induced complications.