What is the initial approach to managing low back pain in the emergency setting?

Emergency Department Approach to Low Back Pain

Initial Red Flag Assessment

The first priority in the emergency department is to rapidly identify red flags that indicate serious pathology requiring immediate imaging or specialist consultation. 1, 2

Screen for these critical red flags:

• Cauda equina syndrome (urinary retention, saddle anesthesia, bilateral leg weakness, fecal incontinence) 3, 1, 4
• History of cancer with metastatic potential to bone 1, 2
• Unexplained weight loss 1, 5
• Fever or recent infection suggesting spinal infection 1, 2
• Significant trauma or history of osteoporosis suggesting fracture 1, 2
• Severe or progressive neurologic deficits 1, 5

Perform a focused neurological examination including straight leg raise test for radiculopathy and assess for midline tenderness, which may indicate vertebral compression fracture (especially with osteoporosis or steroid use) or vertebral infection if accompanied by fever. 1

Imaging Decisions

Do not order routine imaging for uncomplicated acute low back pain without red flags. 3, 1, 2 This is one of the most important principles in emergency management, as unnecessary imaging exposes patients to radiation, increases healthcare costs, and leads to worse patient outcomes without clinical benefit. 3, 2, 6

Order immediate MRI without contrast if:

• Cauda equina syndrome is suspected (urgent MRI assessment is recommended for all patients with new-onset urinary symptoms in the context of low back pain) 3, 1
• Severe or progressive neurologic deficits are present 1, 5
• Serious underlying condition (malignancy, infection, inflammation) is suspected 3, 1

Consider plain radiography only if:

• Risk factors for vertebral compression fracture exist (osteoporosis, steroid use, significant trauma) 1, 5
• Symptoms persist after 4-6 weeks of conservative management 1, 5

Medication Management

Prescribe NSAIDs as first-line therapy for most patients, with acetaminophen as an alternative for those with contraindications to NSAIDs. 3, 1, 2

• NSAIDs (e.g., ibuprofen 400 mg every 4-6 hours) are more effective than acetaminophen for pain relief, though acetaminophen has a more favorable safety profile. 3, 7
• Avoid systemic corticosteroids as they have not shown greater effectiveness than placebo. 1, 2
• Avoid opioids for long-term management due to risks without clear long-term benefit. 1, 2, 5
• Consider muscle relaxants (e.g., cyclobenzaprine 5 mg three times daily) for short-term use in acute muscle spasm, though drowsiness is common. 8

Activity and Self-Care Instructions

Advise patients to remain active within pain limits rather than prescribing bed rest. 3, 1, 2 Most patients experience substantial improvement in the first month with activity modification. 2

Provide these specific instructions:

• Continue normal activities as tolerated; avoid prolonged bed rest (maximum 2-3 days if severe symptoms require it) 3, 9
• Apply heat with heating pads or heated blankets for short-term relief 3, 1
• Reassure patients that acute low back pain is typically self-limiting and benign 3, 2

Disposition and Follow-Up

Discharge most patients with uncomplicated low back pain with instructions to return if red flags develop. 1, 2

Arrange follow-up reassessment if:

• Symptoms persist or worsen after 1 month 1, 2, 5
• Patient is older, has signs of radiculopathy or spinal stenosis, or has worsening symptoms (consider earlier reassessment) 1, 2, 5
• Symptoms persist beyond 4-6 weeks despite conservative management (consider imaging if not previously performed and referral for physical therapy) 1, 2, 5

Obtain urgent neurosurgical consultation if:

• Cauda equina syndrome is confirmed or highly suspected 1, 4, 9
• Severe or progressive neurologic deficits are present 1, 9

Critical Pitfalls to Avoid

• Ordering routine imaging for uncomplicated acute low back pain exposes patients to unnecessary radiation without clinical benefit and increases healthcare utilization. 3, 1, 2, 6
• Missing cauda equina syndrome by failing to ask about urinary retention, saddle anesthesia, and bilateral leg weakness. 3, 1, 4
• Prescribing prolonged bed rest worsens outcomes compared to maintaining activity. 3, 1, 2
• Failing to assess psychosocial factors (depression, passive coping strategies, job dissatisfaction, catastrophizing) that predict poorer outcomes and delayed recovery. 2, 5
• Overreliance on opioids for pain management without considering risks and lack of long-term efficacy. 1, 2, 5