A metanalysis by Calabrese et al. The MRI and angiogram do provide important information to the neurosurgeon. Although meningeal biopsy alone may be sufficient, a brain biopsy is usually performed as well and may provide additional data. The finding on biopsy is granulomatous inflammation of the vessels although some patients with classic presentation and angiographic findings will only have nonspecific inflammation. The majority of other possiblities discussed earlier may be discarded by the history, presentation and laboratory data.
Treatment consists of high dose steroids and cyclophosphamide.
There are no well established prospective trials analyzing treatment, but retrospective data shows no significant differences between groups treated with steroids alone and combination therapy. The current standard remains combination therapy. The primary differences are a normal CSF and a rapid and dramatic response to steroids. It is unclear how much of a role vasospasm plays in this disease since calcium channel blockers may also relieve symptoms. Anecdotal reports have indicated that arterial lesions seen in patients with symptoms less than 12 months often reverse after treatment.