Acute Lower Back Pain

Aetiology

  • Most back pain is innocent and self-limiting

Risk factors for simple back pain

  • Previous back pain
  • Heavy lifting/frequent bending
  • Repetitive work with exposure to vibration

Investigations

Examination

  • General appearance
  • Vital signs
  • Back examination
    • Gait
    • Look - from side and back
    • Feel - SPs, steps, SI joints
    • Move - flexion, extension, lateral bending, rotation
  • Other tests: SLR, muscle strength, sensation, deep tendon reflexes

When to investigate - red flags

General
  • Failure to improve after 4-6 weeks of conservative therapy
  • Unrelenting night pain or pain at rest
  • Progressive motor or sensory deficit
Cancer
  • Age > 50 years
  • Unintended weight loss
  • History of cancer
  • Pain at night and in recumberncy
Infection
  • Fever/chills
  • Recent infection
  • Immunosuppression
  • IV drug use
  • Dental status
  • Foreign travel

Radiology

  • X-ray - not used routinely
    • Young men - SI joint to exclude anklysing spondylitis
    • Elderly - to exclude vertebral collapse, other fractures, malignancy
  • CT - limited application in acute LPB without red flags
    • Good for bony pathology, foreign implants, spinal fusion planning
  • MRI - provides details of soft tissues
  • Bone scan - increased bone scan, metastases, tumours, osteoid osteoma
  • PET/SPECT - increased uptake in high turnover areas

Lab

  • Indicated if red flags present
  • FBC, U+Es, inflammatory markers
  • Malignany e.g. PSA, acid phosphatase
  • Infection
  • Metabolic causes e.g. alk phos, Ca2+, HLAB-27

Management of simple back pain

Non-pharmacological

  • Explanation and re-assurance
  • Advice on activity and exercise

Pharmacological

  • WHO pain ladder - simple analgesics → opiates for severe pain → injections

Complementary and alternative medicine

  • Physiotherapy
  • Acupuncture, chiropractor, osteopath, massages