Acute Low Back Pain

See Also

Definitions

Low Back Pain
1. Pain distribution between the costal angles and the gluteal folds
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
Duration
1. Acute: Less than 4 weeks
2. Subacute: 4 to 12 weeks
3. Chronic: More than 12 weeks
Radiation
1. Sciatica with pain radiating down one or both legs

Epidemiology

Age of onset: Typically first episode occurs between ages 20-40 years old
Low Back Pain is the 5th most common presenting complaint to physician office visits
1. Responsible for 2.63 Million U.S. Emergency Department visits per year
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
Chronic Low Back Pain Prevalence
1. U.S.: 13% (severe in 30% of this subset with Chronic Low Back Pain)
2. Worldwide: 23%

Precautions

Of back pain presentations to the emergency department, 1 in 350 have a spinal emergency (e.g. Spinal Epidural Abscess)
1. See Low Back Pain Red Flags

History

See Low Back Pain History
See Serious Low Back Symptoms (Low Back Pain Red Flags)
See Thoracolumbar Trauma
Presentations
1. Mechanical Low Back Pain
2. Radicular or neuropathic Low Back Pain
3. Idiopathic or nonspecific Low Back Pain (70% of cases)

Exam

Back should be exposed (e.g. in gown) to allow for adequate palpation and visualization
See Lumbar Spine Anatomy
See Low Back Exam

Differential Diagnosis

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
Non-mechanical Causes
1. See Low Back Pain Red Flags
2. Spondyloarthropathy
  1. Ankylosing Spondylitis
  2. Reiter's Syndrome
3. Spinal Infection (Spinal Osteomyelitis, Spinal Epidural Abscess, Discitis)
4. Osteoporosis (Vertebral Compression Fracture)
5. Spinal Neoplasm (Spine Metastases)
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%)

Simple Musculoskeletal Low Back Pain
1. Indicated if no Low Back Pain Red Flags
2. Conservative therapy for 6 weeks
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 below the knee (4%)

See Lumbar Disc Herniation
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
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. MRI Lumbosacral Spine
  2. Immediate Consultation for possible Discectomy

Evaluation
Acute Low Back Pain with Possible Spinal Infection

See Spinal Infection
Low risk patients (significant risk factors, reassuring history and exam)
1. No imaging needed
Moderate risk patients (risk factors present, but no motor deficits)
1. Obtain CRP and ESR and if elevated obtain MRI
High risk patients (motor deficits identified)
1. Obtain MRI

Evaluation
Acute Low Back Pain suggestive of Lumbar Stenosis (3%)

Exclude Cauda Equina Syndrome by history and exam (see above)
Indication
1. Seen in older patients
2. Leg and back pain relieved when sitting
Conservative management in most cases
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

Evaluation
Acute Low Back Pain Suggestive of Vertebral Fracture

Obtain L-Spine XRay
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

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)
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
Low Back Pain with normal Neurologic Exam, no Incontinence and a cancer history
1. Routine repeat evaluation with primary provider
2. Consider Lumbar MRI
References
1. Della-Giustina and Spangler in Herbert (2013) EM:Rap 13(11): 6

Imaging

See Low Back Imaging
See Low Back Pain Red Flags
Precautions
1. A careful history and examination is the most important evaluation measure in Low Back Pain
2. Most patients with Low Back Pain will have Musculoskeletal Low Back Pain (95% will resolve within 6 weeks)
3. Limit imaging to indications as below, including Low Back Pain Red Flags and prolonged >6 weeks
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
Lumbar Spine CT Indications
1. Spinal Trauma
2. Vertebral Fracture
3. Vertebral dislocation
4. Spondylolisthesis
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

Acute Low Back Pain (95%)
1. Resolution in 1 week: 50%
2. Resolution in 8 weeks: 90%
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
Chronic Low Back Pain (<5%)

Management

See Low Back Pain Management
See Return to Work in Lumbar Back Pain
See Low Back Rehabilitation
See Low Back Muscle Fusion Rehabilitation
See McKenzie Method

Prognosis

Risk of progression from Acute Low Back Pain to Chronic Low Back Pain
1. PICKUP Score
  1. https://www.evidencio.com/models/show/1119
2. Orebro Musculoskeletal Pain Screening Questionnaire
  1. https://orthotoolkit.com/ompsq-sf/
3. STarT Back Calculator
  1. https://startback.hfac.keele.ac.uk/training/resources/startback-online/

Resources

Keele STarT Back Approach (YouTube) for patients at risk of progressing to Chronic Low Back Pain
1. https://www.youtube.com/watch?v=tHMJf74buW4
Bob and Brad's Back Pain Playlist (YouTube)
1. https://www.youtube.com/playlist?list=PL8l32k1r15l73-noQNhmHILi3BvtMpvU7

References