What is the best course of action for a 42-year-old female with persistent right-sided low back pain radiating down the posterior right leg, uncontrolled with naproxen (nonsteroidal anti-inflammatory drug (NSAID)) and gabapentin, and partially relieved with ketorolac (NSAID) injection?

Immediate Management: Obtain MRI and Refer for Specialist Evaluation

This patient requires MRI imaging now and specialist referral (neurology, pain management, or spine surgery) rather than another ketorolac injection, as she has persistent radiculopathy symptoms for two weeks that have failed multiple conservative treatments.

Clinical Reasoning

This patient presents with classic lumbar radiculopathy (right-sided low back pain radiating down the posterior right leg in a dermatomal pattern), which has persisted for two weeks despite trials of NSAIDs, muscle relaxants, and gabapentin. The American College of Physicians/American Pain Society guidelines specifically address this scenario.

Why Imaging is Indicated Now

• Patients with persistent low back pain and signs or symptoms of radiculopathy should be evaluated with MRI (preferred) or CT only if they are potential candidates for surgery or epidural steroid injection 1
• After two weeks of failed conservative management including NSAIDs, muscle relaxants, and gabapentin, this patient meets criteria for imaging as she is now a potential candidate for epidural steroid injection or surgical evaluation 1
• MRI is preferred over CT because it provides better visualization of soft tissue, vertebral marrow, and the spinal canal without ionizing radiation 1
• The natural history of lumbar disc herniation with radiculopathy shows improvement within the first 4 weeks with noninvasive management in most patients, but for those with persistent radicular symptoms despite noninvasive therapy, discectomy or epidural steroids are potential treatment options 1

Why Another Ketorolac Injection is Not Appropriate

• Ketorolac provides only symptomatic relief without addressing the underlying pathology causing her radiculopathy 1
• She already received ketorolac yesterday with only partial relief, indicating inadequate response to this approach 1
• NSAIDs (including ketorolac) are first-line medications for nonspecific low back pain, but this patient has moved beyond simple nonspecific pain into persistent radiculopathy requiring definitive diagnosis 1
• Extended courses of medications should be reserved for patients clearly showing continued benefits from therapy without major adverse events, which is not the case here 1

Recommended Treatment Algorithm

Step 1: Obtain MRI Lumbar Spine Immediately

• Order MRI lumbar spine (preferred over CT) to evaluate for disc herniation with nerve root compression 1, 2
• This imaging is justified because she has persistent symptoms beyond conservative management and is now a candidate for interventional treatment 1

Step 2: Optimize Medical Management While Awaiting Imaging

• Continue gabapentin 400mg, as it provides small, short-term benefits for radiculopathy 1, 2
• Consider increasing gabapentin dose if tolerated, as current dosing may be subtherapeutic 1
• Continue NSAIDs (naproxen) for pain control, but recognize these provide only symptomatic relief 1
• Add a skeletal muscle relaxant (cyclobenzaprine, tizanidine, or metaxalone) for short-term relief if muscle spasm is contributing, though she has already tried this class 1, 2

Step 3: Refer to Specialist Based on MRI Results

• For confirmed nerve root compression: Refer to pain management for epidural steroid injection consideration 1, 2
• For significant disc herniation with persistent symptoms: Refer to spine surgery for surgical evaluation 1
• For unclear findings or continued symptoms: Refer to neurology for comprehensive evaluation 1

Step 4: Physical Therapy Referral

• Initiate physical therapy focused on McKenzie method or spine stabilization exercises, which may decrease recurrent pain and need for healthcare services 3
• Physical therapy is appropriate even while awaiting specialist evaluation 2

Critical Pitfalls to Avoid

• Do not continue symptomatic treatment with repeated injections without obtaining diagnostic imaging to identify the underlying cause 1, 2
• Do not delay imaging in patients with persistent radiculopathy who have failed conservative management, as this delays definitive treatment 1
• Do not prescribe prolonged bed rest, as this causes deconditioning and worsens symptoms 1, 2
• Do not rely solely on pain medications without addressing the structural pathology causing nerve root compression 1, 2
• Do not attribute symptoms to simple muscle strain when radicular symptoms are present, as this represents a different pathophysiologic process requiring different management 1

Red Flags to Monitor

While this patient currently denies red flags, she should be counseled to seek immediate emergency evaluation if she develops:

• Progressive motor weakness or sensory deficits 1, 3
• New-onset bowel or bladder incontinence or urinary retention 1, 3
• Saddle anesthesia 1, 3
• Loss of anal sphincter tone 3

These would indicate cauda equina syndrome requiring immediate surgical evaluation 1, 3.