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Horse's tail in bamboo spine: the ‘cauda equina syndrome in ankylosing spondylitis’
  1. Christine Lo1,
  2. Krishnan Padmakumari Sivaraman Nair1,
  3. Charles Anthony Jozef Romanowski2,
  4. Fiona Wendy Fawthorpe3,
  5. Ralf-Björn Lindert1
  1. 1Department of Neurology, Royal Hallamshire Hospital, Sheffield, UK
  2. 2Directorate of Medical Imaging and Medical Physics Royal Hallamshire Hospital, Sheffield, UK
  3. 3Department of Rheumatology, The Rotherham General Hospital, Rotherham, UK
  1. Correspondence to Dr Krishnan Padmakumari Sivaraman Nair, Department of Neurology, Royal Hallamshire Hospital, Sheffield S10 2JF, UK; siva.nair{at}

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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

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Table 1

Neurological complications of ankylosing spondylitis

Case report

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 …

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  • Contributors All authors reviewed and contributed to the text. CL: Literature search, drafting of the initial version of the article. KPSN: idea, review of literature, drafting of the text and editing. CAJR: literature review,writing of radiological aspect and slection and editing of the figures. FWF: reviewed and contributed to the text. RL: reviewed and contributed to the text.

  • Competing interests None.

  • Ethics approval

  • Provenance and peer review Not commissioned; externally peer reviewed. This paper was reviewed by Aaron Berkowitz, Boston, USA.

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