Assessment of Peripheral Neuropathy in Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease primarily affecting the axial skeleton, leading to persistent back pain, stiffness, and progressive functional impairment.

Pain in AS has been attributed to inflammation; however, accumulating evidence suggests that non-inflammatory mechanisms, including neuropathic pain and central sensitization, play a significant role in the overall pain experience.

Previous studies using screening tools such as Pain DETECT and LANSS questionnaires have reported that a considerable proportion of patients exhibit neuropathic pain features, with prevalence ranging from approximately 28% to over 50%. Moreover, neuropathic pain has been associated with higher disease activity scores, worse functional status, and impaired quality of life.

In addition, central sensitization defined as an amplification of neural signaling within the central nervous system has been proposed as a key contributor to chronic pain in AS. Neuroimaging and psychophysical studies have demonstrated alterations in brain structure and pain processing in AS patients, supporting the presence of central pain mechanisms.

Peripheral neuropathy may also occur in AS, potentially due to chronic inflammation, immune-mediated pathways, or mechanical and treatment-related factors. Electrophysiological evaluation using nerve conduction studies (NCS) provides an objective method for detecting large-fiber neuropathy and has revealed peripheral nervous system involvement in a subset of AS patients.

Disease activity in AS is commonly assessed using the Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ASDAS-CRP), while disease-specific quality of life can be evaluated using the Ankylosing Spondylitis Quality of Life (ASQoL) questionnaire. Understanding the interaction between inflammatory activity, neuropathic pain, and central sensitization is essential for optimizing patient management.