Atraumatic low back pain is a common complaint in the ED. For most patients, a thorough history and physical exam is sufficient to exonerate causes that threaten life or neurological function. For a small subset, however, MRI may be required. ALiEM has partnered with the ACEP E-QUAL Network to promote clinical practice improvements through a series of podcasts. In our first installment, we focus on this common presentation. We review highlights from an interview with Dr. Jonathan Edlow, Vice Chair of Emergency Medicine at Beth Israel Deaconess, about the presentation and evaluation of low back pain. Afterward be sure to check out the podcast in full.
4 Can’t Miss Causes and 3 Red Flags
The 4 causes of atraumatic back pain that are most important for an emergency provider to consider include:
- Central Disc Herniation
- Epidural Hematoma
- Epidural Abscess
We frequently risk-stratify patients for these etiologies in terms of “red flags” – points from the history that suggest a patient’s back pain may be from a serious cause. A combination of these symptoms is much more predictive than one individual red flag, and 3 in particular are best validated:
- Personal history of cancer
- Corticosteroid use
- Anti-coagulant use
Learn to Lean Into Your Neurological Exam
Even in the absence of red flag symptoms, any focal neurological deficit should be accounted for with a diagnosis or explanation. It is possible for a patient to have a life or neurologically threatening cause of back pain and have no red flag symptoms or risk factors.
Key points from the physical exam that are often missed or underappreciated include:
- Babinski sign
MRI: Not Without Side Effects
MRI does not help a large majority of patients. Consider the side effects of unwarranted imaging: consults, unnecessary steroid injections, and potentially even surgery. If we take a moment to slow down, most patients are not asking for an MRI, but instead asking for a provider to give an explanation for their symptoms and provide some relief and reassurance.
Red, Green, and the Everything In-between
You can think of patients with atraumatic back pain as falling into 3 buckets: Red, Green, and Intermediate. Most patients fall into the Green category: no red flag symptoms, normal neurological exam, and able to comfortably exit the ED with NSAIDs and a follow-up plan. On the other end of the spectrum, a small but important minority are high risk and warrant expedited imaging. For those in between, consider spine consultation or inflammatory markers to help risk-stratify.