Diagnostic and prognostic relevance of neuromuscular biopsy in primary Sjögren's syndrome-related neuropathy.

OBJECTIVE

To evaluate the clinicobiologic presentation in patients with primary Sjögren's syndrome (SS)-related peripheral neuropathy, the histologic results of neuromuscular biopsy (NMB), and clinical outcome, and to identify prognostic factors.

METHODS

We retrospectively studied clinical and biologic presentation of 40 patients with primary SS-related neuropathy who underwent NMB. Prognostic factors of clinical outcome were assessed by univariate and multivariate analysis.

RESULTS

Patients with vasculitis (lymphocytic [n = 8] or necrotizing [n = 14]) had a higher prevalence of acute-onset neuropathy, multiple mononeuropathy, sensorimotor involvement, vascular purpura, general symptoms, increased C-reactive protein level, positivity for rheumatoid factor, hypocomplementemia, and monoclonal gammopathy compared with those without vasculitis (n = 18). Comparison between patients with necrotizing or lymphocytic vasculitis did not reveal significant differences in clinical or biologic presentation except for the presence of general symptoms and rheumatoid factor. Regarding clinical evolution, the results of NMB (P < 0.0001), in particular the presence of necrotizing vasculitis (P < 0.001), an acute neuropathy onset (P < 0.0001), general symptoms (P < 0.0001), multiple mononeuropathy (P = 0.0007), presence of sensorimotor involvement (P = 0.002), and increased C-reactive protein level (P = 0.008), were significantly associated with a better outcome in univariate analysis. In multivariate analysis, NMB resulting in the identification of patients with necrotizing vasculitis was the only variable that remained significantly associated with a better outcome (P = 0.01).

CONCLUSION

NMB is necessary to identify patients with necrotizing vasculitis, who have a better response to immunosuppressive therapy. NMB might therefore have both a diagnostic and prognostic relevance in primary SS-related neuropathy.