Small fiber neuropathies: expanding their etiologies

Area of Science:

• Neurology
• Immunology
• Pathophysiology

Background:

• Small fiber neuropathy (SFN) is linked to various metabolic, immune, infectious, toxic, drug-related, and hereditary conditions.
• Pathophysiological mechanisms underlying SFN are actively being investigated to identify novel therapeutic targets.
• The specific clinical presentation of SFN can offer crucial clues to its underlying cause.

Purpose of the Study:

• To review recent advancements in understanding the expanding etiologies of small fiber neuropathy.
• To highlight the growing list of conditions associated with SFN and their potential pathophysiological mechanisms.
• To discuss how understanding SFN causes can inform treatment strategies.

Main Methods:

• Literature review focusing on developments in the last 18 months.
• Analysis of recent findings on immunological etiologies, including new auto-antibodies.
• Examination of emerging concepts such as syndromic SFN and non-length-dependent patterns.

Main Results:

• Recent research emphasizes immunological causes of SFN, partly influenced by the COVID-19 pandemic.
• New auto-antibodies associated with SFN have been identified.
• Immune-mediated SFN may present with non-length-dependent patterns, differing from classical SFN phenotypes.
• Small fiber pathology is increasingly recognized in conditions without typical SFN pain features (syndromic SFN).

Conclusions:

• The range of known causes for SFN continues to expand, offering new insights for treatment development.
• Recognizing the diverse clinical presentations associated with different SFN etiologies is crucial for accurate diagnosis and management.
• Further research is needed to fully understand the clinical relevance of syndromic SFN.