Ankylosing spondylitis and multiple sclerosis.

Ankylosing Spondylitis can be associated with extra-articular involvement. Besides internal and ocular complications, neurological manifestations such as single root lesions, compression of the myelum or the cauda equina syndrome have also been described. We present a patient with ankylosing spondylitis who developed a monophasic myelopathy resembling multiple sclerosis. Literature data show no conclusive evidence for an increased association of ankylosing spondylitis and multiple sclerosis. However, a monophasic myelopathy may be a separate neurological manifestation associated with ankylosing spondylitis.