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Acute Low Back Pain

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Acute Low Back Pain, Musculoskeletal Low Back Pain, Mechanical Low Back Pain, Low Back Pain, Lumbago

  • Definition
  1. Low Back Pain
    1. Pain distribution between the costal angles and the gluteal folds
  2. Mechanical Low Back Pain
    1. Back pain with origin in the spine, intervertebral discs and surrounding soft tissue
    2. Includes strains, disc Herniation, Spondylosis, Spondylolisthesis, Spondylolysis, compression Fractures
  3. Duration
    1. Acute: Less than 4 weeks
    2. Subacute: 4 to 12 weeks
    3. Chronic: More than 12 weeks
  4. Radiation
    1. Sciatica with pain radiating down one or both legs
  • Epidemiology
  1. Age of onset: Typically first episode occurs between ages 20-40 years old
  2. Chronic Low Back Pain affects 23% of the population worldwide
  3. Frequent, severe Low Back Pain Prevalence occurs in 8% or 11.8 of 145 Million Employed Adults (U.S., 2015)
    1. Ages 18-29: 5.9% (1.99 Million)
    2. Ages 30-44: 7.9% (3.74 Million)
    3. Ages 45-64: 9.7% (5.52 Million)
    4. Age >65: 8.7% (0.63 Million)
    5. CDC Low Back Pain
      1. https://wwwn.cdc.gov/Niosh-whc/chart/ohs-lowback/illness?OU=FS_PAINLB&T=A&V=R
  • Exam
  1. Back should be exposed (e.g. in gown) to allow for adequate palpation and visualization
  2. See Low Back Exam
  3. See Lumbar Spine Anatomy
  • Differential Diagnosis
  1. Mechanical Causes (90%)
    1. Lumbosacral strain (70%)
      1. Isolated Trauma or repetitive overuse
    2. Lumbar Spondylosis (10%)
      1. Chronic disc degeneration and secondary foraminal narrowing in over age 40 years old
    3. Lumbar Disc Herniation (5%)
      1. Occurs at L4-5 or L5-S1 in 90-95% of cases
    4. Spondylolysis (<5%)
      1. Young athletes with frequent lumbar hyperextension (e.g. gymnastics, football)
    5. Vertebral Compression Fracture (4%)
      1. Vertebral Fracture and collapse, typically due to Osteoporosis, and most commonly at L1 and L4
    6. Spondylolisthesis (3-4%)
      1. Vertebral slippage anteriorly, at L5 in 90% of cases, with Leg Pain, Paresthesias and weakness
    7. Lumbar Spinal Stenosis (3%)
      1. Narrowing of lumbar spinal canal with back pain and leg numbness, weakness better with rest
  2. Non-mechanical Causes
    1. See Low Back Pain Red Flags
    2. Spondyloarthropathy
      1. Ankylosing Spondylitis
      2. Reiter's Syndrome
    3. Spinal Infection
    4. Osteoporosis
    5. Cancer
    6. Referred visceral pain
      1. Abdominal Aortic Aneurysm
      2. Pancreatic Cancer
      3. Genitourinary cancer
    7. Lumbar Stenosis
    8. Cauda Equina Syndrome
  • Evaluation
  • Acute Low Back Pain without radicular symptoms (93%)
  1. Simple Musculoskeletal Low Back Pain
    1. Indicated if no Low Back Pain Red Flags
    2. Conservative therapy for 6 weeks
  2. Complicated Low Back Pain
    1. Indications: Risk of cancer or infection
      1. See Low Back Pain Red Flags
    2. Lab work
      1. Complete Blood Count
      2. Urinalysis
      3. Erythrocyte Sedimentation Rate (ESR)
        1. Highly suggestive if ESR >50 mm per hour
      4. Prostate Specific Antigen (PSA)
        1. Consider in men over age 50
    3. Initial Imaging: L-Spine XRay Indications
      1. Risk factors for non-mechanical cause (see above)
      2. Erythrocyte Sedimentation Rate (ESR) >20 mm/hour
      3. Low Back Pain Red Flags
    4. Additional management if indicated by XRay or ESR
      1. Consider MRI Spine (preferred imaging)
      2. Consider Bone Scan
      3. Consider orthopedic Consultation
  • Evaluation
  • Acute Low Back Pain with radiculopathy past the knee (4%)
  1. See Lumbar Disc Herniation
  2. Conservative management in 99% of cases
    1. Indicated if no indications for urgent evaluation
    2. CT or MRI Spine if not improving by 6 weeks
  3. Urgent evaluation in 1% of cases
    1. Indications
      1. Cauda Equina Syndrome
      2. Rapid progression of neurologic deficit
      3. Urinary Retention
      4. Saddle anesthesia
      5. Bilateral neurologic deficit
    2. Protocol
      1. Immediate Consultation for possible discectomy
      2. MRI Lumbosacral Spine
  1. Indication
    1. Seen in older patients
    2. Leg and back pain relieved when sitting
  2. Conservative management in most cases
  3. Evaluation for more significant stenosis
    1. Indications
      1. Failed conservative therapy
      2. Intolerable symptoms
      3. Neurologic deficit
    2. Protocol
      1. CT or MRI Spine
      2. Consultation for possible laminectomy
  1. Obtain L-Spine XRay
  2. Negative XRay and persistent symptoms >10 days
    1. Consider bone scan or CT Spine
    2. Consider orthopedic or spine Consultation
  • Evaluation
  • Acute Low Back Pain with Cancer History
  1. New or worse over prior 1-3 days radiculopathy Incontinence, weakness or sensory change and a cancer history
    1. Risk of tumor with cord compression
    2. Dexamethasone 10 mg orally or IV AND
    3. Emergent MRI (typically from Cervical Spine through Lumbar Spine)
  2. Stable low back symptoms >1 week without progression and a cancer history
    1. Consider Dexamethasone
    2. Lumbar MRI (typically from Cervical Spine through Lumbar Spine) within 24 hours
  3. Low Back Pain with normal Neurologic Exam, no Incontinence and a cancer history
    1. Routine repeat evaluation with primary provider
    2. Consider Lumbar MRI
  4. References
    1. Della-Giustina and Spangler in Herbert (2013) EM:Rap 13(11): 6
  • Imaging
  1. See Low Back Imaging
  2. See Low Back Pain Red Flags
  3. Lumbar Spine XRay Indications
    1. Consider in age over 50 years or under 18 years old, or acute Lumbar Spine Trauma
    2. Vertebral Fracture
    3. Spondylolisthesis
  4. Lumbar Spine CT Indications
    1. Spinal Trauma
    2. Vertebral Fracture
    3. Vertebral dislocation
    4. Spondylolisthesis
  5. Lumbar Spine MRI Indications
    1. Lumbosacral Radiculopathy >6 weeks despite conservative management
    2. Spinal Epidural Abscess (Spinal Osteomyelitis)
    3. Spinal Cord Tumor
    4. Cauda Equina Syndrome (or spinal stenosis)
    5. Nontraumatic vascular injuries of the spine
  • Course
  1. Acute Low Back Pain (95%)
    1. Resolution in 1 week: 50%
    2. Resolution in 8 weeks: 90%
  2. Recurrent Low Back Pain
    1. Recurs in at least 25% of patients within 1-2 years
    2. Moderate to severe in at least a third of patients
  3. Chronic Low Back Pain (<5%)