Idiopathic steroid responsive chronic lymphocytic meningitis - clinical features and long term outcome in 17 patients

Background: Some patients with chronic lymphocytic meningitis appear to respond to corticosteroid treatment, but, investigations fail to identify the cause. The use of corticosteroids in patients with chronic meningitis is controversial and the long term outcome is unclear. Aim: To review the long term outcome in 17 patients with the syndrome of idiopathic steroid responsive chronic lymphocytic meningitis. Methods: Review of patients' records and examination of surviving patients 1.5 to 17.5 years (median 8.8 years) after presentation. Results: The cause of the steroid responsive chronic meningitis was found during follow up in two of the 17 patients: Wegener's granulomatosis and multiple sclerosis in one patient each. A cause was not found in the other 15 patients. Seven of those patients eventually recovered and corticosteroids were withdrawn after six weeks to six years without a recurrence of symptoms. Four patients improved transiently, but died six months to 26 years after starting treatment; in two, steroids were withdrawn a few weeks before death. Four patients had active chronic meningitis and reduction in the dose of corticosteroids was associated with a recurrence of symptoms. Leptomeningeal and brain biopsy in eight patients showed non-specific abnormalities which were not helpful in the diagnosis. Conclusions: A subgroup of patients with idiopathic chronic lymphocytic meningitis responds to corticosteroids. Leptomeningeal biopsy and long term follow up seldom identify the underlying cause in these patients. Steroid treatment must be undertaken with caution, even after infective causes of chronic meningitis have been excluded.