Rheumatoid meningitis

Epidemiology

 * Sex: 59% female, 41% male, similar to that seen in rheumatoid arthritis (RA).
 * Age: 37-80, mean 65 years
 * Coexisting rheumatoid arthritis: up to 16% may have no history of RA at all, and 45% had RA duration of less than 5 years. Median duration of RA before meningitis onset was 8.5 years among women but 2 years among men.

Signs/symptoms
Symptoms are episodic in half of cases
 * TIA or stroke-like symptoms (56%)
 * Confusion (34%)
 * Seizure-like activity (33%)
 * Headaches (28%)

Serum studies

 * ESR, CRP elevated in the majority
 * Rheumatoid factor: positive in nearly all cases in which it was reported.
 * Anti-CCP: positive in the vast majority in which it was reported

CSF

 * WBCs: lymphocytic pleocytosis in the vast majority, ranging from 0-237 cells/μL, 45-96% lymphocytes.  The majority had WBC counts in the 7-40 cells/μL range.
 * Protein: elevated in the majority, ranging from 32-267 mg/dL. Most had protein levels in the 40-85 mg/dL range.
 * Glucose: usually normal

Imaging

 * Leptomeningeal enhancement (in 69%)
 * Pachymeningeal enhancement
 * Subarachnoid FLAIR hyperintensity

Brain biopsy

 * Chronic inflammation
 * Rheumatoid nodule: necrotizing center surrounded by multinucleated giant cells and inflammatory cells
 * Vasculitis: in approximately half of cases

Prognosis

 * Pulse-dose steroids
 * Cyclophosphamide
 * Rituximab
 * Methotrexate