Neuropathic Pain in Axial Spondyloarthritis

September 2018

Axial spondyloarthritis (axSpA) is a chronic rheumatic disease that primarily affects the spine and other joints. Common features of spondyloarthritis include inflammatory back pain, as well as pain and inflammation in the pelvis, neck, intestine, eyes, heels, and various larger joints. A key symptom in axSpA patients is significant back pain, usually brought on by inflammation or structural changes from new bone formation.

However, a specific type of pain – called neuropathic pain – which can occur in axSpA, has not been well studied. Neuropathic pain occurs when the nervous system is damaged or affected by disease. It can result in pain from originally non-painful stimuli or sudden spontaneous sensations, such as burning, tingling or stabbing. There is no consistent cause for neuropathic pain in axSpA patients, but it can potentially lead to additional complications in an already complex disease. A study, published in the Journal of Clinical Rheumatology, sought to assess the frequency of neuropathic pain (NeP) in axSpA patients, as well as the effects of NeP on their overall wellbeing.

The study utilized two separate methods to determine the presence of NeP in individuals with axSpA: the Douleur Neuropathique en 4 Questions^[1] and the painDETECT^[2] questionnaire. The Douleur Neuropathique en 4 Questions detected NeP in 31.4% of axSpA patients, while the painDETECT questionnaire recognized NeP in 33.5% of axSpA patients.

Upon analysis, despite similar pain characteristics between NeP patients and non-NeP patients, pain severity was much higher in NeP patients. These patients were found to have significantly decreased qualities of life indicated by higher visual pain, fatigue, depression, anxiety, Bath Ankylosing Spondylitis Disease Activity Index^[3] scores and Ankylosing Spondylitis Disease Activity Scores^[4]. Demographically, it was found that NeP was more frequent in women, but no other factors, such as age or ethnicity were examined.

In conclusion, the study suggests that around one third of those living with axial spondyloarthritis (including both non-radiographic axial spondyloarthritis and ankylosing spondylitis patients) likely have some degree of NeP. Though the study did not address the total number of patients diagnosed with NeP, it has been established that they experience a decreased quality of life. NeP should be taken into consideration during patient evaluation and in determining treatment plans.

[1] Douleur Neuropathique en 4 Questions – A Yes/No questionnaire that tallies the participants’ results and can predict a possible diagnosis of NeP. If you answer Yes to at least four out of 10 questions regarding your symptoms, then you have a >90% chance of receiving a NeP diagnosis.

[2] painDETECT – A seven question form that addresses the quality of neuropathic pain symptoms. The questionnaire requires patients to rate their symptoms on a scale and then compare their final score to expected results. On a scale from -1 to 38, a score of <=12 indicates that a NeP component is unlikely in the individual. A score of >=19 suggests that the patient has a >90% chance of having a NeP component.

[3] Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) – A quick and subjective measure in which patients classify their discomfort level on a scale of 1-10 in 6 different categories, such as fatigue and stiffness, with the numbers then being averaged.

[4] Ankylosing Spondylitis Disease Activity Score (ASDAS) – A similar test as the BASDAI that utilizes a combination of subjective measures from 1 to10 as well as objective scientific measures, such as C-Reactive Protein and Erythrocyte Sedimentation Rates to asses disease activity in Ankylosing Spondylitis patients.