Visual loss from idiopathic intracranial pachymeningitis.

We report three patients with chronic headaches and optic neuropathy due to widespread meningeal thickening shown on enhanced MRI; all had biopsy-proven intracranial pachymeningitis (fibrosclerosis of the meninges). Two patients had bilateral optic neuropathy, elevated CSF protein, and polyclonal serum hypergammaglobulinemia. They developed temporal lobe cortical necrosis or sagittal sinus thrombosis, presumably due to compromised dural venous drainage from extensive meningeal fibrosis. The other patient had multiple cranial nerve palsies and unilateral optic neuropathy with normal CSF. Corticosteroid therapy improved visual function in all three patients, although all had persisting visual deficits. Gadolinium-enhanced MRI was essential in identifying meningeal inflammation and locating suitable biopsy sites.