Nerve ultrasound findings in Sjögren's syndrome-associated neuropathy

The phenotype of Sjögren's syndrome-associated neuropathy has been better characterized in recent years. However, Sjögren's syndrome-associated neuropathy remains an underdiagnosed entity with only few insights considering the pathomechanisms of nerve damage. Nerve ultrasound has proven to be a useful and efficient tool in detecting nerve damage of autoimmune origin. We, therefore, aimed to evaluate this method for Sjögren's syndrome-associated neuropathy.

Patients with Sjögren's syndrome and clinical signs of neuropathy underwent sonographic examination of both median and ulnar nerves. Nerve thickening was classified for cross-sectional areas of >12 mm² at the median nerve and for >10 mm² at the ulnar nerve. Fascicle thickening was documented for cross-sectional areas ≥5 mm² at the median and ≥3 mm² at the ulnar nerve.

Forty-three patients were included in the analysis (median age 60 years [interquartile range 53-73 years], female rate 60%). 31/43 patients (72%) showed abnormalities on nerve ultrasound, while nerve thickening was found more frequently than fascicle thickening (90% vs. 52% of patients with sonographic abnormalities, respectively). Abnormal findings were observed more frequently at the median nerve and in proximal localization. Abnormal findings on nerve conduction studies were evident in 36/43 patients (84%). Nerve conduction studies revealed a tendency of demyelinating nerve damage patterns being associated with abnormal findings on nerve ultrasound.

In addition to nerve conduction studies, nerve ultrasound may have a supporting role in the diagnosis of Sjögren's syndrome-associated neuropathy. Also, our data support an immune-mediated inflammatory demyelinating pathogenesis of Sjögren's syndrome-associated neuropathy.