UMEM Educational Pearls

Title: What are the real Red Flags of Back pain that predict fracture or malignancy

Keywords: back pain, red flag (PubMed Search)

Posted: 11/29/2014 by Michael Bond, MD
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A recent meta-analysis of 14 studies looked at the typical red flags of back pain to see which ones actually truly increase the risk that the patient will have a fracture or malignancy.

The typical historical red flags that are taught are

Age under 18 or over 50
Pain lasting more than 6 weeks
History of cancer
Fever and chills
Night sweats, unexplained weight loss
Recent bacterial infection
Unremitting pain despite rest and analgesics
Night pain
Intravenous drug users
Immunocompromised
Major trauma
Minor trauma in the elderly

And physical exam red flags are

Fever
Writhing in pain
Bowel or bladder incontinence
Saddle anesthesia
Decreased or absent anal sphincter tone
Perianal or perineal sensory loss
Severe or progressive neurologic defect
Major motor weakness

However, this meta-analysis showed that the only red flags that actually increased the risk of fracture or malignancy were

Older Age Post test Probability 9% (95% CI 3% to 25%)
Prolonged corticosteroid use Post test Probability 33% (95% CI 10% to 67%)
Severe trauma Post test Probability 11% (95% CI 8 % to 16%)
Presence of contusion or abrasion Post test Probability 62% (95% CI 49% to 74%)

So this study highlights that a lot of the red flags that we have learned do not actually increase the risk fracture or malignancy, although some like fever, IVDA, and immunocomproromised increase the risk of epidural abscesses, which was not addressed in this meta-analysis.

The take home point for me is that plain radiographs/CT scans are probably only needed in patients with older age, prolonged corticosteroid use, severe trauma or presence o contusion or abrasion. If you are really worried about others with back pain just proceed directly to MRI as the plain films/CT scans are not going to be very helpful.

References

Downie A, Williams CM, Henschke N, et al. Red flags to screen for malignancy and fracture in patients with low back pain. British Journal of Sports Medicine. 2014;48(20):1518–1518. doi:10.1136/bjsports-2014-f7095rep.