Chronic meningitis without predisposing illness--a review of 83 cases.

Eighty-three previously healthy patients with chronic meningitis presenting to a general hospital were reviewed. The single most common cause was tuberculosis (40 per cent) with cryptococcosis (7 per cent), malignancy (8 per cent) and other definable causes much less frequent. In one-third of patients (34 per cent) no cause was found although most appeared to respond to treatment either with anti-tuberculosis drugs or steroids. There were some differences in clinical presentation, the clinical picture being most characteristic in tuberculous meningitis and malignant meningitis. However, there were frequent exceptions to any general rule and, particularly in adults, the clinical features and changes in cell count, protein and glucose in the cerebrospinal fluid (CSF) did not reliably distinguish one form of chronic meningitis from another. Cerebral and meningeal biopsy produced disappointing results with respect to practical guidance in management. It is often necessary to begin treatment before a cause has been identified. Important points in management include the early use of anti-tuberculosis treatment and the difficulty in deciding on a trial of treatment with corticosteroids or amphotericin B. Not emphasised in previous reports is a subgroup of patients with idiopathic chronic meningitis who are responsive to treatment with steroids. Those patients tend to follow a more prolonged indolent course and often require long-term immunosuppression to control symptoms.