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Problems with Red Flags in Diagnosing Low Back Pain

There is considerable heterogeneity in "red flags" amongst numerous low back pain (LBP) guidelines worldwide.  A "red flags" denotes a finding, which if present, imparts a significantly high risk of underlying serious spinal pathology with considerable subsequent morbidity or mortality.

A systematic review in the European Spine Journal examined "red flags" for the diagnosis of low back pain from various published guidelines published between 2000 and 2015.

They reviewed 16 guidelines from 15 different countries. All guidelines focused on the management of patients with low back pain in a primary care or multidisciplinary care setting. Only five of these had "red flags" within their guidelines.

A total of 46 red flags were identified relating to 4 main categories of serious pathology: malignancy, fracture, cauda equina syndrome and infection.  Overall, there was a lack of consensus between guidelines over which red flags to endorse, and the evidence and accuracy of recommended red flags was lacking. For instance, 8 guidelines based their choice of red flags on consensus or previous guidelines; 5 did not provide any reference to support the choice of red flags, and 3 guidelines were poorly referenced.

Nevertheless, the majority of guidelines agreed on red flags for:

  • Fracture: major/significant trauma or the use of steroids/immunosuppressors
  • Malignancy: history of prior cancer or unintentional weight loss
  • Bone pain at night or at rest: considered as a red flag for various underlying pathologies.
  • Cauda equina syndrome: Sudden onset of new urinary retention, fecal incontinence, saddle anesthesia, radicular (leg) pain often bilateral, loss of voluntary rectal sphincter contraction
  • Ankylosis spondylitis: Night pain, back pain in younger adults, inflammatory morning stiffness, history of uveitis or inflammatory bowel disease.
  • Aneurysm: increasing age (>50 yrs), sudden pain, pulsatile abdominal mass

A wide variety of red flags were found in worldwide guidelines for low back pain, with a lack of consensus between guidelines for which red flags to endorse. Evidence for their predictive value is needed.

Join The Discussion

Leonard H. Calabrese, DO

| Aug 02, 2016 5:41 pm

Jack these type of studies drive me nuts! Wringing our hands over such clinical maxims is useful to a point but calling fro quantitative evidence to validate such pearls is largely nonsense. Red flags should merely make us THINK! I do not believe that every diagnosis in this area or others can be approach quantitatively or in a Baysean manner. Some conditions are just to important to ignore (i.e. they are MUST RULE OUTS) particular when clinical judgement suggests their presence. For example fever is a woefully non-specific sign but in the setting of back pain makes me very concerned over infection or cancer. Of course not every fever plus back pain is sinister in origin. Red flags should make people play being a doctor. They should raise a warning. Red flags need not trigger critical pathways but they should break you out of automatic pilot mode.. Remember that critical paths are great if you are on the road and not in the woods Lenny Calabrese
LC - I love your 10,000 foot, sage view of this. I reported on the heterogeneity, but you correctly identified the value in "red flags". That being said this paper is a GREAT compendium of red flags for LBP and such has great teaching value!

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Disclosures
The author has no conflicts of interest to disclose related to this subject