Case Report of Transverse Myelitis in a Patient Receiving Etanercept for Rheumatoid Arthritis

Etanercept is a monoclonal antibody targeted against Tumour Necrosis Factor-alpha (TNF-a) which is an effective treatment for rheumatoid arthritis and is in cases where conventional disease modifying agents such as methotrexate have failed. Neurological complications of treatment have been documented. We describe a case of transverse myelitis occurring in a 48 year-old lady with RA since 1994 who had been receiving etanercept for four years. 1. Case Presentation Mrs. S, a 48-year-old lady with RA of 11 years duration responded well to treatment with etanercept, with an improvement in her Disease Activity Score (DAS) from a pretreatment value of 6.98 in June 2005 to 2.69 within five months. In December 2008, she began to develop bilateral numbness and tingling in her lower limbs and the ulnar border of her left hand. She also experienced numbness in the perineum and associated bowel urgency. On examination, tone, power, reflexes, and coordination were normal throughout; however she had reduced vibration sense to the waist, joint position sense to the feet, and temperature to the knees bilaterally. Temperature sensation was also reduced in the ulnar fingers of her left hand. Investigations for neuropathy showed a folate level slightly reduced at 2.2？ng/mL and a normal Vitamin B12. She was seronegative for rheumatoid factor and negative for aquaporin-4 antibody (to exclude Devic’s disease). Antinuclear antibody (Hep-2) was positive at 1？:？160 with a speckled pattern but anti-dsDNA antibody was negative making lupus less likely. Lumbar puncture biochemistry and microbiology were normal, with no oligoclonal band, and MRI head was also normal. MRI demonstrated abnormal signal return from the cervical spine from the level of C3 to the upper boarder of T1 (Figure 1). A diagnosis of cervical myelitis was made. Etanercept was discontinued four months after the development of neuropathy, with no noticeable improvement in her condition over the next six months. Despite the addition of folate supplements, a short course of methylprednisolone and amitriptyline, she continues to have significant neurological symptoms with impaired mobility and walking stamina. Figure 1: MRI spine showed a long intramedullary inflammatory lesion in the cord from C3 to the upper boarder of T1 on T1-weighted MRI imaging. 2. Discussion Inhibition of TNF, a cytokine critically involved in the acute inflammatory response in RA, is an established treatment for autoimmune arthropathy. Etanercept is a soluble (TNF-a) receptor-Fc fusion protein which specifically targets and inhibits the