Lower back pain

Background

• Pain lasting >6wks is risk factor for more serious disease
• Night pain and unrelenting pain are worrisome symptoms
• Back pain in IV drug user is spinal infection until proven otherwise
• 95% of herniated discks occur at L4-L5 or L5-S1 (for both pain extends below the knee)

Clinical Features

• See Back Pain (Red Flags)
• Musculoskeletal pain
  • Located primarily in the back w/ possible radiation into the buttock/thighs
  • Pain worse w/ movement but improves w/ rest
• Spinal stenosis
  • Bilateral sciatic pain worsened by walking (pseudoclaudication), prolonged standing **Pain relieved by forward flexion
• Sciatica
  • Radicular back pain in the distribution of a lumbar or sacral nerve root
    • Anything that compresses the nerve roots, cauda equina, or cord can cause sciatica
  • Pain worsened by coughing, Valsalva, sitting; relieved by lying in supine position
  • Occurs in only 1% of pts w/ back pain
  • Present in 95% of pts who have a symptomatic herniated disk

DDX

• See Back Pain (DDX)

Work-Up

1. Pregnancy test
2. Exam
   1. Straight leg raise testing
      1. Screening exam for a herniated disk (Sn 68-80%)
      2. Lifting leg causes radicular pain of affected leg radiating to BELOW the knee
      3. Pain is worsened by ankle dorsiflexion
   2. Crossed Straight leg raise testing (high Sp, low Sn)
      1. Lifting the asymptomatic leg causes radicular pain down the affected leg
   3. Nerve root compromise
   4. Rectal exam (if concerned for cord compression)
3. Labs
   1. Only necessary if concerned for infection, tumor, or rheumatologic cause
      1. CBC, UA, ESR (90-98% Sn for infectious etiology)
4. Imaging
   1. Plain films
      1. Only necessary if suspect fracture, tumor, or infection
   2. MRI
      1. Only necessary if suspect infection, neoplasm, epidural compression syndromes
      2. Consider for back pain >6-8wks
   3. US
      1. Rule-out AAA

Treatment

• Nonspecific Back Pain (musculoskeletal)
  • Instruct to continue daily activities using pain as limiting factor
  • Meds
    • NSAIDs or acetaminophen
      • 1st line therapy
    • Opioids
      • Appropriate for moderate-severe pain but only for limited duration (1-2wks)
    • Muscle relaxants
      • Efficacy appears equal to NSAIDs
      • Diazepam 5-10mg PO q6-8hr OR methocarbamol 1000-1500mg PO QID
• Sciatica
  • Treatment is the same as for musculoskeletal back pain
  • 80% of pts will ultimately improve without surgery
• Spinal Stenosis
  • Treatment is the same as for musculoskeletal back pain

See Also

• Back Pain (Red Flags)
• Back Pain (DDX)

Source

• Tintinalli