Screening for: Fractures, Malignancy, Cauda Equina,..

This post is for healthcare providers.

What does the current research tell us about screening for common red flags? 

Most of the recommended signs in the identification of the following 4 red flag presentations in lower back pain have high false positive rates, and poor diagnostic accuracy when screening for: 

1. Spinal Fracture
2. Malignancy
3. Spondyloarthritis (SpA) /  Inflammatory Back Pain (IBP)
4. Cauda Equina Syndrome

Spinal Fracture: Reviews in 2013 and 2013 of red flags for vertebral fractures in patients with LBP found, “The available evidence does not support the use of many red flags to specifically screen for vertebral fracture in patients presenting for LBP.” While the most reliable red flags for spinal fracture were corticosteroids, age >70 years, contusion/abrasion and significant trauma.

Malignancy: A 2013 review concluded, “For most red flags, there is insufficient evidence to provide recommendations regarding their diagnostic accuracy or usefulness for detecting spinal malignancy.” Downie reported, “the red flag with the highest post-test probability for detection of spinal malignancy was history of malignancy. 

Spondyloarthropathy:  Estimated to have a 5% prevalence amongst chronic LBP sufferers. Two papers Sieper and Burgos-Vargas gave similar criteria:

• 35 – 40 yo  onset
• insidious onset
• improved by movement, not rest
• pain second half of night which gets better with getting up
• improvement by NSAID’s within 48 hours.
• alternating buttock pain

Interestingly there is some debate on testing / imaging for SpA.  Plain radiography and ESR tests are probably not ideal for early diagnosis, HLBA27 testing (which is not that sensitive) and then MRI are preferred. Early diagnosis is important to lessen disability, through exercise and early anti TNF therapy.

Cauda Equina Syndrome:  CES is rare, many working in private practice will never see a case. “There is low evidence that individual symptoms or signs from the patient history or clinical examination, respectively, can be used to diagnose CES.” Fairbank 2011  Of course, it is best to error on the side of caution when saddle anaesthesia is present (Gibson).

A 2009 study looked at 1,172 consecutive patients receiving primary care for acute low back pain. At the initial consultation, clinicians recorded responses to 25 red flag questions and then provided an initial diagnosis.

• 11 cases (0.9%) of serious pathology, including 8 cases of fracture
• most patients (80.4%) had at least 1 red flag 
• only 3 of the red flags for fracture recommended for use in clinical guidelines were informative: prolonged use of corticosteroids, age >70 years, and significant trauma.
• clinicians identified 5 of the 11 cases of serious pathology at the initial consultation and made 6 false-positive diagnoses.
• there were no cases of cancer or infection
• 8 cases of fracture, 1 cauda equina and 2 inflammatory disorders

American College of Physicians guidelines on when to refer for investigation was summarised by Deyo, Jarvik and Chou (2014):

• Immediate radiography and blood analysis of erythrocyte sedimentation rate (ESR) is recommended for patients with:
  • Major risk factors for cancer such as history of cancer, multiple risk factors (i.e. flags) for cancer, and/or a strong clinical suspicion of cancer. Should the radiography and ESR be negative, but a strong clinical suspicion of cancer remains, then proceeding to MRI is recommended.
• Immediate MRI is recommended for patients with:
  • Risk factors for spinal infection such as fever and history of injection drug use or recent infection.
  • Symptoms of caudal equina syndrome (new urinary retention, fecal incontinence, saddle anaesthesia)
  • Severe neurological deficits such as progressive motor weakness or motor deficits at multiple level neurologic levels)
• Deferment of radiography and +/- ESR until after a trial of treatment in patients with:
  • Weaker risk factors for cancer
  • Risk factors for inflammatory back pain
  • Risk factors for vertebral fracture
• Deferment of MRI until after a trial of treatment in patients with:
  • Signs of symptoms of radiculopathy or spinal stenosis

For a more detailed article on this topic Mark Gibson wrote a great post in 2014.