Polyneuropathy and the sural/radial sensory nerve action potential ratio in primary Sjögren's syndrome

Objectives: Polyneuropathy is the most common neurological complication in primary Sjögren's syndrome (pSS). A ratio of sural nerve and superficial radial nerve sensorial action potential amplitudes (SRARs) of <0.4 is an indicator for early axonal neuropathy. We evaluated the polyneuropathies and SRARs in pSS patients.Method: Fifty-two female patients who were diagnosed with pSS according to the European-American Consensus Criteria and 45 healthy controls were enrolled. Nerve conduction studies were performed to diagnose polyneuropathy. Sensory axonal polyneuropathy was diagnosed in three patients, so SRARs were compared in 49 patients and 50 healthy controls.Results: Fifty-two patients with pSS underwent nerve conduction tests. The sural sensory nerve action potential (SNAP) was <6 µV in threepatients and they were diagnosed with sensory axonal neuropathy. SRARs were evaluated in 49 female patients, with a mean age of 51.98 ± 10.79 years and 50 healthy controls with a mean age of 50.52 ± 12.55 years. The mean disease duration was 7.59 ± 6.17 years. The SRAR values were different between the patient and control groups. SRAR was <0.4 in 20.4% of the patient group and <0.4 in 6% of the control group. The SRAR value was not statistically different within the patient group based on anti-Ro and anti-La.Discussion: The potential for neurological involvement in patients with pSS who have no signs or injury should be evaluated because nervous system involvement in pSS is a negative prognostic factor. SRAR in patients with pSS can be used as a marker for the early detection of axonal neuropathy.