Rheumatoid arthritis is a chronic, systemic, autoimmune inflammatory disease that mainly affects the joints and periarticular soft tissues. Baricitinib (Olumiant®) is an oral, targeted synthetic DMARD that inhibits JAK1 and JAK2, which are implicated in the pathogenesis of rheumatoid arthritis (RA). Nerve conduction studies (NCSs) are an essential tool in the evaluation of the peripheral nervous system. The sensory nerve action potential (SNAP) provides information on the sensory nerve axon and its pathway from the distal receptors in the skin to the dorsal root ganglia, while the compound muscle action potential (CMAP) is an assessment of the motor nerve fibers from their origins in the anterior horn cell to their termination along muscle fibers.

Inclusion Criteria:

1. Patients fulfill the 2010 ACR/EULAR classification criteria of RA
2. Age above 18 years old.
3. Patient cooperative and can answer questions

Exclusion Criteria:

1. Other rheumatologic or collagen diseases.
2. Age below 18 years and above 65 years.
3. Uncooperative patients.
4. Patients with other causes of peripheral neuropathy as Diabetes mellitus.