Evaluation of Subclinical Peripheral Neuropathy in Ankylosing Spondylitis Patients on Biological Treatment

Abstract

Background: Ankylosing spondylitis (AS) is a chronic autoimmune inflammatory disease affecting the axial skeleton. For patients with  persistent symptoms, biological therapy mainly tumor necrosis factor (TNF) inhibitors and interleukin (IL)-17 inhibitors have proved  efficacy in controlling disease progression. However, Peripheral neurological side effects have been reported.

Objective: This work aimed  to investigate the effect of biological agents, including anti-TNF-α and anti-IL 17, on peripheral nerves in patients with ankylosing  spondylitis (AS).

Patients and Methods: This prospective study included 30 biologic-naïve patients with AS, with no neuropathic symptoms or signs. A  nerve conduction study (NCS) was performed for each patient at baseline and then after duration of follow-up (12 months). Biological  therapy was administered to the patients during this period, including anti-TNF-a agents (5 etanercept, 6 adalimumab, and 5 golimumab)  and IL-17 inhibitors (14 secukinumab). Patients were subjected to clinical examination, activity score: Bath Ankylosing  Spondylitis Disease Activity Index (BASDAI), and lab evaluation. NCS was performed where motor and sensory latencies, amplitude, and  conduction velocities were recorded and compared before and after treatment.

Results: There was a statistically significant increase in motor and sensory latencies in all recorded nerves after treatment, however,  these latencies remained within normal physiological ranges. No significant changes were observed in other parameters including  amplitude, conduction velocity, or f-waves.

Conclusion: It could be concluded that biological therapies, like TNF-α and IL-17 inhibitors, have significantly advanced AS treatment.  However, rare neurological side effects, such as demyelinating events, need careful monitoring. Our findings and existing literature  highlight the importance of assessing neurological involvement throughout treatment to actively manage adverse effects and improve  patient outcomes.