Subclinical peripheral nerve involvement in patients with rheumatoid arthritis

Clinical involvement of the peripheral nervous system is uncommon in rheumatoid arthritis (RA); the most common disorders are multiple mononeuritis, sensorimotor neuropathy, and entrapment neuropathy. This study was undertaken to investigate the occurrence of electrophysiologically evident peripheral nerve involvement in RA patients without a clinical history of peripheral nerve involvement.

Forty RA patients were examined neurologically and electrophysiologically, and sural nerve biopsies were performed in 4.

No patient reported symptoms or signs of peripheral nerve involvement. Twenty-six patients (65%) exhibited electrophysiologic findings consistent with a sensorimotor neuropathy (in 2 of them a carpal tunnel syndrome was also present), while 3 patients showed isolated carpal tunnel syndrome. There was a moderate loss of myelinated fibers in 3 of the 4 nerve biopsy samples, and all showed an increased number of endo- and perineurial vessels and some signs of axonal degeneration.

Patients with RA may have electrophysiologic and histologic findings of peripheral nerve damage, even in the absence of clinical evidence of peripheral nerve involvement.