Objective: To examine the clinicopathologic features of the noncompressive neuropathies in rheumatoid arthritis (RA).
Methods: We studied 32 patients with RA and peripheral neuropathy whose nerve and/or muscle biopsy specimens exhibited necrotizing vasculitis. Morphologic analysis of nerve specimens included light and electron microscopy studies and teased fiber preparation. Survival was evaluated, and the prognostic values of clinical, biologic, and pathologic features were assessed by Cox proportional hazards model. A prognostic assessment based on the significant variables was devised to estimate the probability of survival of any individual patient.
Results: Epi- and/or perineurial vasculitis was observed with the same frequency in the 17 patients with sensory and motor deficit and the 15 patients with sensory neuropathies and was associated with axonal degeneration of an average of 77.7% of the nerve fibers. The mean followup was 7.2 years, and the overall survival rate at 5 years was 57%. A full prolonged remission of the vasculitis was observed in 53% of the patients; relapse occurred in 25%. The factors correlated with mortality, in decreasing order of significance, were clinical cutaneous vasculitis (P = 0.0003), neuropathy affecting 3 or 4 limbs (P = 0.03), and depressed level of C4 (P < 0.05). The prognostic assessment indicated a wide range of 5-year probabilities of survival, from < 1% to 93%.
Conclusion: Necrotizing vasculitis is responsible for the different patterns of noncompressive neuropathies in RA, including mononeuritis multiplex and distal symmetric sensory or sensorimotor neuropathy. Cutaneous vasculitis, multifocal neuropathy, and depressed C4 level were the 3 independent variables which best predicted mortality. We propose a prognostic assessment according to these variables, to stratify patients to receive more aggressive or less aggressive therapy.