1. Principles of Back Pain Outpatient Internal Medicine

2. Cases: Mr. A 43y/o male, works for a lumber company, strained his back loading his truck 2 wks ago. Had to take off work 2/2 pain, muscle spasm. Hurts to move. Mrs. B 68y/o female, retired, known OA in knees & hands, now feeling low back pain x2months. No h/o trauma. Paraspinal muscles tight & sore. Hurts to move.

3. What could be causing their pain? Nerve impingement (roots, nerves) Muscle trauma Disc pain Facet joint pain Bony pain

4. How do you differentiate? History: age, red flag signs –Incontinence, bladder retention, saddle anesthesia – think cord compression or cauda equina syndrome – sudden, excruciating pain with minimal trauma – think insufficiency fracture 2/2 osteoporosis or tumor –Fever, IV drugs – infection Physical exam: –Straight leg raise – think disc herniation –Piriformis tenderness – think sciatic entrapment in the piriformis muscle –Muscle pain/tightness – raises suspicion for muscle injury, although pain from any source can cause reactive muscle spasm –Tenderness over bony prominence – think fracture

5. A word on sciatica Sciatica is a symptom, not a diagnosis Inflammation of the sciatic nerve can happen at many places, including: –L4/L5 nerve roots (most common!) –Piriformis or other muscle entrapment of sciatic nerve –Spinal cord itself (spinal stenosis)

6. When do you image? –Most low back pain resolves in 6 weeks, so no imaging is needed –Consider imaging if: Young (<20) Old (>50) Hx of tumor Trauma Night/rest pain Systemic symptoms Red flag symptoms

7. How do you image? X-rays: –Good for detecting fracture –Can document presence or absence of arthritic changes, but won’t assess nerve involvement MRI: –Delineates disc disease, nerve impingement –Detects tumors –Use contrast if there is a history of back surgery or tumors

8. Examples L3 endplates should be parallel, like L4. Collapse implies fracture. L4 L3White circle shows disc herniation in above sagittal view of MRI Red arrow shows nerve impingement by disc/osteophyte in axial view of MRI

9. Treatment For most back pain, NSAIDs, heat, early return to normal activity as tolerated x 6 weeks. Other options: –Narcotics – patches for constant pain, prn pills for intermittent pain –Muscle relaxers if significant spasm is causing problems –Injections (steroid/lidocaine) – epidural, facet joint, disc, piriformis –Surgery – spinal fusion

10. Cases: Mr. A Negative straight leg raise, significant paraspinal tightness and tenderness. Exquisite pain with turning. Dx: likely muscle tear. Tx: NSAIDs, heat, muscle relaxers, mild activity. Mrs. B Positive straight leg raise, moderate paraspinal tenderness on palpation. Pain in back and leg on arising from seated position Dx: likely herniated disc Tx: NSAIDs, heat, mild activity, consider imaging since 2+ months. Consider referral to anesthesia for injections.

11. References: Skyrme, A. Common Spinal Disorders. Remedica, 2003. Stone, R. Harrison’s Principles of Internal Medicine. McGraw-Hill, 2001. Wheeler, S. et al. “Approach to the diagnosis and evaluation of low back pain in adults”. UpToDate. 2008.