Neuropathic Hand Pain in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, inflammatory rheumatic disease that predominantly affecting peripheral joints. Patients with RA are suffered from severe hand pain and functional loss because of synovitis in hand joints. The fact that patients with low disease activity may complain from hand pain suggests that pain is mediated by mechanisms other than inflammation. Contribution of central sensitization to pain sensation of RA patients is of interest currently. Several authors reported the neuropathic characteristics of hand pain in RA. Hand pain is primarily nociceptive in RA patients but the possibility of variances in cutaneous sensitivity due to nociceptive input from joints has been suggested. Increased sensitivity with light touch has been demonstrated over hands of RA patients. In RA patients, alterations in central processing of somatosensory function and allodynia over inflamed joints have been reported. Poor sleep quality is another issue for RA patients and it's association with pain was reported. However impact of neuropathic hand pain on sleep quality was not understood exactly probably due to the scarce of the studies investigating this association. Also, to the best of investigators' knowledge, the relation between neuropathic component of pain and sensory threshold alterations in rheumatoid hand was not studied to date.

So, investigators have aimed to estimate prevalence of neuropathic hand pain in RA patients and it's relation with sleep quality and sensory thresholds. For this purpose a case-control study design was planned. Age- and sex-matched control subjects will be chosen among individuals submitted to out-patient clinic with nociceptive/mechanical pain complaint other than in hand lasting more than three months. Also whether sensory thresholds in rheumatoid hands differ from healthy hands will be assessed. Participants in control group will be subjected to same exclusion criteria too.

This design will allow the investigators to determine whether hand pain in RA patients displays neuropathic character more frequently than any other chronic nociceptive pain does. Moreover, it will be possible to compare sensory thresholds between healthy and rheumatoid hand. RA patients diagnosed according to the 1987 American College of Rheumatology criteria will be recruited. Demographics and disease related variables will be recorded.

Inclusion criteria

• Being diagnosed with RA according to the 1987 ACR Criteria
• Visual Analogue Scale hand pain score ≥ 3

Exclusion criteria

• Diabetes mellitus, renal insufficiency, hypothyroidism
• Carpal tunnel syndrome, postherpetic neuralgia, cervical spinal cord compression
• Cervical radiculopathy
• Fibromyalgia
• Malignancy
• Hand muscle weakness of even one grade on Medical Research Council Manual Muscle Testing scale
• Upper motor neuron sign on physical examination of hands
• Pregnancy
• In the last three months medical treatment leading to neuropathy (colchicine etc.)
• In the last three months drug use for the treatment of fibromyalgia, depression or anxiety