Neurological disturbances in ankylosing spondylitis.

Case history A 56 year old man presented with a seven week history of tingling in both buttocks associated with numbness of the right buttock which radiated down the back of the leg to the level of the knee. He also gave a four year history of numbness along the heel and sole of the right foot. There was no motor symptoms. No specific urinary or bowel symptoms were evident. In the past he had experienced intermittent low back pain, but he had been asymptomatic in that regard for many years. On examination there was impaired sensation along the right S2 dermatome and also perianally in the S3 to S5 distribution on the right side. Movement of the spine was limited in all directions. No focal tenderness was elicited. Examination was otherwise normal. Plain radiographs of the lumbar spine were obtained.