Neuropathic Foot and Ankle in Rheumatoid Arthritis : Ultrasound and Nerve Conduction Study

Rheumatoid arthritis (RA) is a common chronic systemic autoimmune disease that primarily affects the lining of the synovial joints which symmetrically involves the small joints, can cause cartilage and bone damage and associated with progressive disability, premature deaths, and socioeconomic burdens . In RA, neuropathic pain "which is defined as pain caused by a lesion or a disease of the somatosensory system" , could be suggested by :nerve compression, associated comorbidities and vascuilitis . Despite the recent advancement in RA treatment, neuropathic pain remains a cause of persistent pain even in controlled disease activity. The prevalence of clinical neuropathy varies from 0.5% to 85% in patients with RA, which can cause functional disability . Foot and ankle pain is highly prevalent in RA with peripheral neuropathy is a common contributor to it . In previous studies , it was found that the most foot neuropathies are of tarsal tunnel syndrome, peroneal nerve entrapment and pure sensory axonal neuropathy. For evaluation of neuropathic foot and ankle in RA , electrophysiological and imaging techniques can be very useful. Nerve conduction study (NCS) is the electrodiagnostic evaluation of the function of peripheral nerves ,it can provide information regarding the presence, severity and location of a lesion, symmetricity of neuropathy, mononeuropathy or disorders affecting the neuromuscular junctions. Also, the functional modality most involved (sensory or motor) and the predominant pattern of pathology (e.g., axonal, demyelinating, or both. Neuromascular ultrasond(NMUS) is a new modality of diagnosis developed in the past 20 years , and it can assess anatomical abnormalities that can't be evaluated by NCS NMUS being noninvasive and inexpensive diagnostic modality , it has been introduced as a complement to NCS for diagnosis of nerve conditions.