Investigation of Central Sensitization Frequency and Related Factors in Axial Spondyloarthritis Patients

The term axial spondyloarthritis (axSpA) describes a group of chronic inflammatory diseases that characterized with spinal involvement. AxSpA is one of the most common rheumatic diseases and chronic pain and morning stiffness are the main complaints of these patients. Central sensitization is defined as increased response to normal or sub-threshold stimuli of central nervous system and its close relationship with many rheumatological diseases has been demonstrated in several studies. Pain in axSpA patients is generally considered as a result of increased inflammatory burden and structural changes, However, failure to adequate analgesia in every patient whose inflammation is suppressed with anti-inflammatory treatment suggests new pain mechanisms. Central sensitization (CS) is one of these mechanisms and its recognition is only possible by detailed evaluation of the patient. There is no method for the diagnosis of central sensitization is accepted as a gold standard. clinical scales and quantitative sensory testing (QST) widely is used for this purpose widely. The most commonly used QST types include pressure pain threshold (PPT), temporal summation (TS) and conditioned pain modulation (CPM). The well-known scale used for the evaluation of central sensitization is the Central Sensitization Inventory , developed by Mayer et.al in 2011 for detect central sensitization in chronic pain patients. The aim of this study is to evaluate the frequency of central sensitization (CS) in patients with axSpA by means of clinical scales and quantitative sensory testing (QST), to examine related comorbidities and the parameters associated with the development of sensitization in these patients.

The term axial spondyloarthritis (axSpA) describes a group of chronic inflammatory diseases that characterized with spinal involvement. AxSpA is one of the most common rheumatic diseases and chronic pain and morning stiffness are the main complaints of these patients. Central sensitization (CS) is defined as increased response to normal or sub-threshold stimuli of central nervous system and its close relationship with many rheumatological diseases has been demonstrated in several studies. However, data associated with central sensitization in axSpA patients is very limited. The quantitative sensory testing (QST) is commonly used for detection hyperalgesia and allodynia those are accepted main findings in sensitized patients. The most commonly used QST types include pressure pain threshold (PPT), temporal summation (TS) and conditioned pain modulation (CPM).Pressure pain threshold measurement is frequently used to show local / generalized sensitivity increase in patients who develop pain sensitization. For this purpose, the pain response of superficial or deep tissue can be evaluated through mechanical device called algometer. The algometer probe was placed vertically in the each selected point and pressure was increased until the participant reporting pressure became painful. The first pressure value at which pain is felt is considered the PPT of that point. TS is defined as a progressive increase in pain response with repetitive painful stimuli. This condition is also known as wind-up phenomenon and play a role to development CS. CPM, known as one of the main mechanisms of endogenous analgesia, is based on the principle that pain perception can be reduced with painful stimulus applied to different areas according to the "pain inhibits pain" model. In the CPM testing, it is aimed to investigate the modulator effect of two different painful stimuli on each other. The diagnosis of CS can be made with QST or with Central Sensitization Inventory (CSI). The aim of this study is to evaluate the frequency of central sensitization (CS) in patients with axial spondyloarthritis (AxSpA) by means of clinical scales and quantitative sensory testing (QST), to examine related comorbidities and the parameters associated with the development of sensitization in these patients. The patients with AxSpa and healthy controls will be included in this study. QST which consists of pressure pain threshold (PPT), temporal summation (TS) and conditioned pain modulation (CPM) will be applied to the patient and control groups. Disease activity (BASDAI), functional status (ASQoL, ILBPDI), sleep quality (PSQI), pain (VAS pain), depression (BDI) and fatigue (FSS) will be assessed. Fibromyalgia (FIRST) and other comorbidities will be investigated. Patients will be divided as the ones with and without CS according to the central sensitization inventory (CSI) and the results will be compared. After data collection, analysis will be performed with the appropriate statistical method

Eligibility Criteria:
Inclusion Criteria:

Diagnosed with axSpA according to the Assessment of SpondyloArthritis International Society (ASAS) criteria Aged between 18-65 years

Exclusion Criteria:

Had an other rheumatic diseases, peripheral vascular disease, peripheral neuropathy and spine disease (e.g., symptomatic herniated disc, spinal stenosis), Using centrally acting pain medications (e.g., pregabaline, duloxetine, opioids) or glucocorticoids (\>10 mg prednisone or its equivalent) within 3 months of study enrollment

The exclusion criteria of the control grup were same as that of the patients.