Practice Lesson of the Week

Clinical management of injured patients with ankylosing spondylitis

BMJ 2009; 339 doi: https://doi.org/10.1136/bmj.b2568 (Published 17 July 2009) Cite this as: BMJ 2009;339:b2568
  1. Steve Fordham, specialist trainee 5 emergency medicine,
  2. Gavin Lloyd, consultant emergency physician
  1. 1Royal Devon and Exeter Hospital, Exeter EX2 5DW
  1. Correspondence to: gavin.lloyd{at}rdeft.nhs.uk
  • Accepted 3 November 2008

Patients with ankylosing spondylitis are prone to low impact fractures. Maintain a low threshold for medical imaging

Ankylosing spondylitis has a prevalence of approximately 1 in 1000 in the UK.1 Up to 6% of these patients are estimated to experience a vertebral fracture during their lifetime.2 The incidence of major neurological complications following fracture is high (29-92%) with considerable associated morbidity and mortality.3 4 The rate of missed fractures in this population is not formally reported in the literature. We present four cases of missed spinal fracture in patients with ankylosing spondylitis and discuss the management of such patients.

Case reports

Case 1

A 60 year old man with a 30 year history of ankylosing spondylitis walked into the emergency department after a simple fall in his garden. He had sustained a minor head injury and tenderness was elicited in his upper thoracic spine. He was discharged home without x ray, but presented again 14 days later having developed numbness in his thumb, index, and middle fingers bilaterally. Plain x ray and computed tomography imaging showed an unstable fracture dislocation at the C6/7 level (fig1).

Figure1

Fig 1 Unstable fracture dislocation at C6/7 level

Case 2

A 52 year old man with a 15 year history of ankylosing spondylitis, lost control of his motorbike at 40 km/h (25 miles/h) on a wet road and was thrown over the handlebars. He hit his head on the road but did not lose consciousness. On primary survey he had minor midline C5-C7 tenderness, a score of 15 on the Glasgow coma scale, and no other significant injury. Plain films of his cervical spine were viewed by senior members of both orthopaedic and emergency medicine teams and interpreted as normal. He was observed clinically because of the mechanism of injury. Review at four hours established continuing neck pain. A computed tomography scan demonstrated an unstable fracture through the disc space of C6/7. On review of his x ray images, the fracture is visible (fig2).

Figure2

Fig 2 Unstable fracture through disc space of C6/7

Case 3

An independent 81 year old woman fell on to her back from two steps. She was brought into the emergency department fully immobilised saying that she had a “funny feeling” in her legs. Lower limb examination revealed only three fifths power in L3/4/5 distribution bilaterally. Plain x ray images were difficult to interpret, and there was thought to be a fracture at the T6 level. A computed tomography scan revealed unstable fractures of the T3 and T10 vertebrae and spinous process fractures at T1 and T2.

Case 4

A 61 year old man with a 46 year history of ankylosing spondylitis fell backwards while carrying a cupboard up a flight of stairs. He walked into the local minor injuries unit saying he was experiencing thoracolumbar back pain, and was discharged with a diagnosis of soft tissue injury. He presented to the emergency department five days later with ongoing pain and said he had been unable to get out of bed that morning. He had a sensory level at T10 and only two fifths power in his lower limbs bilaterally. Plain x ray films and magnetic resonance imaging demonstrated fractures of the T9 and T12 vertebral bodies with cord compression at the T9 level (fig 3).

Figure3

Fig 3 Fractures of T9 and T12 vertebral bodies with cord compression at T9 level

Discussion

Ankylosing spondylitis is a progressive, chronic inflammatory condition involving the sacroiliac joints and the spine. Because of inflammation and ossification over time the spine fuses, forming fixed deformity and decreased functional activity. This rigidity, often with associated osteoporosis, means spinal fractures can occur with minimal or even no trauma.2

Immediately after injury it is essential that treating healthcare professionals elicit an accurate history for assessment of the severity of the disease and modify management accordingly. Advanced trauma life support principles advise that the cervical spine be immobilised in a neutral position with collar, sandbag, and tape.5 However, many patients with ankylosing spondylitis will have chronic fixed flexion or kyphotic deformity. Immobilisation must be performed according to the individual patient’s needs and can be achieved with hands, pillows, or rolled blankets. Practically this involves asking the patient what their neutral position is (or whether their line of vision feels normal) and stopping if the patient resists attempts to move them. There have been numerous case reports of worsening neurological deficit with inappropriate immobilisation and transfer.6 7 8

Clinical suspicion of fracture in patients with ankylosing spondylitis requires imaging, even if the force involved is allegedly minor. Case 1 above is an example where the need for imaging was not initially appreciated. The most common fracture site is the lower cervical spine, often the hardest area to view with plain radiographs. Multiple fractures can occur. A combination of inadequate views and difficulty in interpretation (because of pre-existing disease) accounts for missed injuries and potential adverse outcomes.7

A low threshold for computed tomography imaging is recommended in cases where radiography is inconclusive or if symptoms persist after a period of observation9; cases 2 and 3 above highlight this. If the clinical features are that of cord or nerve compression then magnetic resonance imaging is the preferred investigation, as demonstrated in case 4. Further transfer of the patient to the scanner will be required and careful immobilisation must be maintained to avoid causing or exacerbating spinal cord injury. In addition patients should be considered for bone density measurement, which can guide future treatment aimed at osteoporosis and fracture prevention.

Notes

Cite this as: BMJ 2009;339:b2568

Footnotes

  • Contributors: Both SF and GL collected the cases and wrote the article. SF is guarantor.

  • Funding: None.

  • Competing interests: None declared.

  • Provenance and peer review: Not commissioned; externally reviewed.

  • Patient consent: Obtained.

References

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