Painful Small‐Fiber Neuropathy in Primary Sjogren's Syndrome

The Clinical Features of Painful Small‐Fiber Neuropathy Suggesting an Origin Linked to Primary Sjögren's Syndrome

Small fiber neuropathy is a condition characterized by severe pain attacks that typically begin in the feet or hands. Some people initially experience a more generalized, whole-body pain. The attacks usually consist of pain described as stabbing or burning, or abnormal skin sensations such as tingling or itchiness. In some individuals, the pain is more severe during times of rest or at night. NIH

Objective

Researchers attempted to determine whether clinical features could tell the difference between painful small‐fiber neuropathy (SFN) related to primary Sjogren's syndrome from idiopathic SFN. Idiopathic means that no specific cause can be identified. 

Methods

They conducted questionnaires and neuro-physiological examinations specific for pain and SFN assessment on 25 patients with pSS‐SFN and 25 patients with idiopathic SFN.

Results

Patients with idio‐SFN had more frequent severe burning sensations and higher mean anxiety scores and daily pain intensity compared to patients with pSS SFN. Conversely, patients with pSS‐SFN had reduced electrochemical skin conductance measured by Sudoscan, and almost half of them had the sensation of walking on cotton wool.

Conclusion

The results suggest that:

•  idiopathic‐SFN  involved more small sensory fibers than pSS‐SFN
• subtle dysfunction of larger sensory fibers and damage of distal autonomic sudomotor innervation may occur in  pSS‐SFN. 
• A practical algorithm is proposed to help to differentiate SFN associated with pSS from idio‐SFN, based on information very easy to obtain by clinical interview.

SOURCE