TY - JOUR T1 - Horse's tail in bamboo spine: the ‘cauda equina syndrome in ankylosing spondylitis’ JF - Practical Neurology JO - Pract Neurol SP - 418 LP - 421 DO - 10.1136/practneurol-2014-000868 VL - 14 IS - 6 AU - Christine Lo AU - Krishnan Padmakumari Sivaraman Nair AU - Charles Anthony Jozef Romanowski AU - Fiona Wendy Fawthorpe AU - Ralf-Björn Lindert Y1 - 2014/12/01 UR - http://pn.bmj.com/content/14/6/418.abstract N2 - Ankylosing spondylitis is the most common of the spondyloarthritides—the group of chronic inflammatory diseases of the axial skeleton that result in low back pain, spinal stiffness and restriction of movement. Extra-axial complications include peripheral arthritis, enthesitis (inflammation of the insertion of tendon into bone) and uveitis. In ankylosing spondylitis, chronic inflammation leads to ossification of the outer fibres of the annulus fibrosus of the intervertebral discs. The curved, bony spicules bridging the vertebral bodies give the impression of a bamboo stem on antero-posterior X-rays of the spine. Neurological complications are uncommon in ankylosing spondylitis and comprise mainly traumatic spinal cord injury (table 1).1 We report a rarely encountered slowly progressive neurological complication: the ‘cauda equina syndrome in ankylosing spondylitis’.1 ,2 View this table:In this windowIn a new windowTable 1 Neurological complications of ankylosing spondylitis A 57-year-old woman with a 36-year history of ankylosing spondylitis presented with sensory changes in the left buttock. She had no weakness or sphincter dysfunction. On examination, there was restricted hip rotation and abduction bilaterally and a diminished left ankle reflex. Straight leg raising test was negative bilaterally and light touch sensation was intact. An X-ray of her pelvis and knees showed fusion of her sacroiliac joints. Despite non-steroidal anti-inflammatory drugs and physiotherapy, her symptoms continued slowly to progress. After 2 years, the altered sensation had spread to the posterior aspect of her … ER -