Cervical myelopathy due to rheumatoid arthritis. Case report and review of the literature.
We present the case report of a 62 year-old female suffering from destructive rheumatoid arthritis (RA) for more than 20 years. She had complaints of progressive gait impairment and numbness in hands and feet. Neurological examination showed an unstable gait and pyramidal tract signs. Anterior atlantoaxial subluxation with pannus formation and cervical myelopathy were demonstrated using conventional X-ray studies and MRI. She was conservatively treated with a soft collar. Treatment with methotrexate and an intensive gait revalidation program were started. RA commonly involves the cervical spine, usually in advanced systemic disease after a mean delay of 16 years. Subluxations of the cervical spine are found in 43 to 86%, 50% of these patients are asymptomatic. The reported rate of neurological impairment due to cervical instability ranges from 7 to 58%. The three most common lesions resulting from cervical RA are atlantoaxial subluxation (50 to 70%), subaxial subluxation (15 to 25%) and cranial settling (20%). It is important to differentiate between cranial settling and atlantoaxial instability, as the latter may have a more benign history with less than 20% showing progressive instability. Cranial settling progresses in 35 to 50% of patients. The commonest presenting features of rheumatoid cervical myelopathy are isolated sensory symptoms. Most patients were found to have multiple neurological deficits once the myelopathy was diagnosed. A mean delay of 31 weeks between the first symptom and the diagnosis of the myelopathy is reported. The sensory symptoms are often misinterpreted as being due to entrapment neuropathy or rheumatoid peripheral neuropathy. Radiographic analysis indicates that the posterior atlantoodontoid interval (< or = 14 mm) is an important parameter that shows excellent correlation with the severity of paralysis.