Spontaneous atlantoaxial subluxation as a presenting manifestation of juvenile ankylosing spondylitis. A case report.

Juvenile-onset ankylosing spondylitis is an unusual disorder which can present with either peripheral arthritis or with more classic hip girdle and back symptoms. Atlantoaxial instability has been recognized as a late complication in only one patient and has not been reported as an early manifestation. This paper presents a case in which atlantoaxial instability and neck pain without neurologic involvement was a presenting manifestation. The laboratory and clinical features of juvenile ankylosing spondylitis are discussed, along with the importance of qualitative sacroiliac joint scintigraphy in the diagnosis of early or confusing cases.