Myelopathy due to atlanto-axial dislocation in a patient with Down's syndrome and rheumatoid arthritis.

A case of Down's syndrome in association with rheumatoid arthritis is described. The patient has spastic diplegia and atlanto-axial dislocation, probably the result of ligamentous laxity which is common in both Down's syndrome and rheumatoid arthritis. This laxity may have been enhanced by tonsillar or deep cervical infection. The myelopathy was thought to be due to the atlanto-axial dislocation. Spinal fusion may reverse the neurological abnormality in some cases.