This paper aims to analyse the etiology, characterisation and outcomes of the different types of peripheral neuropathy in patients with primary Sjögren's syndrome (SS) and their association with clinical and immunological disease expression.
A total of 563 consecutive patients diagnosed with primary SS were evaluated. We retrospectively assessed the results of nerve conduction studies carried out in patients with suspected peripheral nervous system involvement. Peripheral neuropathies were classified into mononeuropathy, mononeuropathy multiplex, polyneuropathy and neuronopathy according to the patterns evidenced by electrodiagnostic studies.
Nerve conduction studies were carried out in 158/563 (28%) SS patients. The results were normal in 49 and abnormal in 109 patients, in whom peripheral neuropathy was diagnosed in 102. After excluding patients with neuropathy associated with other diseases and patients with entrapment mononeuropathies, 55/563 (10%) patients were classified as having SS-related peripheral neuropathy, including axonal sensorimotor polyneuropathy (n=24), pure sensory neuronopathy (n=15), mononeuropathy multiplex (n=15) and demyelinating polyradiculoneuropathy (n=1). In spite of therapy, clinical progression measured by the MOHS scale was observed in 12% of patients with axonal polyneuropathy, 13% of those with mononeuropathy multiplex and 47% of those with neuronopathy. Survival was significantly reduced in patients with peripheral neuropathy (especially in those with mononeuropathy multiplex and axonal polyneuropathy) in comparison with the control group (log rank =0.001).
We found a prevalence of SS-related peripheral neuropathy of 10%. Classification of neuropathy according to the clinical presentation and electrodiagnostic tests may be useful in determining the functional outcome, therapeutic response and survival.