Neuropathic pain syndrome is characterized by chronic, stimulus-independent pain sensation accompanied by hyperalgesia/allodynia and paresthesia. Fibromyalgia (FM) syndrome displays such features. The Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) Pain Scale is an instrument developed and validated to recognize neuropathic pain and set it apart from nociceptive pain.
This study assessed the responses of patients with FM versus patients with rheumatoid arthritis (RA) to the LANSS Pain Scale questionnaire. Twenty patients with FM and 20 patients with RA answered the Fibromyalgia Impact Questionnaire and LANSS Pain Scale questions related to the following neuropathic sensory disturbance domains: dysesthetic, autonomic, evoked, paroxysmal, and thermal.
Pain severity was similar in both groups according to visual analog scale values (5.3 +/- 3.0 for FM v 5.4 +/- 3.1 for RA). There were sharp differences between FM and RA groups in the percentage of affirmative responses to 4 of 5 sensory disturbance questions: dysesthetic (95 v 30), evoked (95 v 35), paroxysmal (90 v 15), and thermal (90 v 20); P <.0001 for each comparison.
The LANSS Pain Scale items may become a useful, easily applied bedside test to differentiate FM pain from the nociceptive pain present in RA and in similar arthritic illnesses.
The high prevalence of associated sensory disturbances supports the notion that FM is a neuropathic pain syndrome.