Multiple dislocations of the cervical spine in a patient with juvenile rheumatoid arthritis and Down's syndrome.

Both Down's syndrome and juvenile rheumatoid arthritis can cause instability of the cervical spine. Patients with Down's syndrome usually have instability of the atlantoaxial joint. With juvenile rheumatoid arthritis, cervical instability is a manifestation of a more generalized process involving ligamentous laxity, posterior facet ankylosis, and growth disturbances of the vertebral bodies. When the two syndromes occur in the same patient, the potential exists for serious cervical instability. In the 14-year-old girl reported here, the two conditions coexisted, and more severe cervical spine involvement occurred than was originally anticipated. Prior awareness of the combined effects of Down's syndrome and juvenile rheumatoid arthritis on the stability of the cervical spine should be useful in the management of future cases.