What are the differentials and initial management for thoracic and lumbar spine pain?

Differential Diagnosis for Thoracic and Lumbar Spine Pain

Immediate Life-Threatening Differentials

Aortic dissection must be ruled out first in thoracic back pain, particularly following sudden physical exertion, presenting with sudden severe tearing pain radiating between shoulder blades, associated with hypertension or connective tissue disorders. 1

• Requires immediate cardiovascular imaging (CT angiography or transesophageal echocardiography) if suspected 1
• Consider especially in patients with hypertension, sudden onset pain, or stimulant use 1

Red Flag Assessment Algorithm

Screen immediately for red flags to determine if urgent imaging or intervention is needed before proceeding with conservative management. 1, 2

Fracture Risk Factors:

• Age >65 years 1, 3
• Chronic corticosteroid use 1, 3
• Known osteoporosis 1, 3
• Midline tenderness on examination 1
• Even minimal trauma in elderly patients warrants imaging 3

Malignancy Indicators:

• History of cancer 1, 2
• Unexplained weight loss 1, 2, 4
• Age >50 years 1
• Constant, unrelenting pain 1, 2
• Night pain 4

Infection/Abscess Signs:

• Fever 1, 2, 4
• Recent infection 1, 2
• Immunosuppression 1, 2
• IV drug use 1, 2
• Constant pain with systemic symptoms 1

Neurologic Emergency Indicators:

• Myelopathy signs (spasticity, hyperreflexia, positive Babinski, bladder dysfunction) require immediate MRI 1, 2
• Progressive motor weakness 1, 2
• Saddle anesthesia 4
• Loss of anal sphincter tone 4
• Bladder or bowel dysfunction 4

Musculoskeletal Differentials (No Red Flags)

Mechanical/Strain Injuries:

• Musculoskeletal strain is the most likely diagnosis in otherwise healthy individuals after overexertion, presenting with myofascial pain in paraspinous soft tissues, typically self-limited and responsive to conservative management within 4 weeks. 1
• No imaging indicated for acute pain (<4 weeks) without red flags 5, 1

Disc-Related Pathology:

• Thoracic disc herniation occurs most commonly below T7 level 1, 2
• One-third of cases have trauma history 1
• Typically affects patients aged 30-50 years 1, 2
• Frequently calcified 1, 2
• Important caveat: Thoracic disc abnormalities (herniations, bulges, annular fissures) are common in asymptomatic patients, so imaging findings do not correlate with symptoms 5

Facet Joint Pain:

• Prevalence in chronic cervical spine pain: 55% 6
• Prevalence in chronic thoracic spine pain: 42% 6
• Prevalence in chronic lumbar spine pain: 31% 6
• Morphologic imaging changes of osteoarthritis do not correlate with pain 5

Radiculopathy:

• Thoracic radiculopathy presents with pain radiating in dermatomal distribution 2
• Typically self-limiting and responsive to non-surgical treatment within 4 weeks 2
• Surgery rarely indicated (1-2% of all discectomies) 2

Fracture-Related Differentials

Osteoporotic Compression Fractures:

• Critical consideration in elderly patients (>65 years) or those on chronic steroids, with low threshold for X-ray imaging 1, 3
• High risk even with minimal or no trauma in older adults 3
• MRI identifies compression fractures even when radiographs are negative and detects marrow edema to determine fracture acuity 3

Schmorl's Node/Herniation:

• Herniation of intervertebral disc through vertebral end-plate 7
• Can cause non-mechanical pain resistant to treatment 7

Initial Management Algorithm

For Acute Pain (<4 weeks) Without Red Flags:

• No imaging indicated 5, 1
• Conservative management with medical management and physical therapy 5
• Extrapolated from low back pain evidence showing routine imaging provides no clinical benefit 5

For Subacute/Chronic Pain (4-12 weeks) With Failed Conservative Management:

• MRI thoracic/lumbar spine without IV contrast is the imaging study of choice 3, 2
• Can identify disc herniations, nerve root compression, spinal stenosis, and facet arthropathy 2

For Red Flags Present:

• Fracture risk factors: Thoracic/lumbar spine X-ray as initial study 1
• Malignancy or infection concern: MRI with and without IV contrast 1, 3, 2
• Myelopathy or progressive neurologic deficits: Immediate MRI without contrast 1, 2

Special Population Considerations:

• Elderly patients (>65 years) require lower threshold for imaging due to increased fracture and malignancy risk 1, 3
• MRI without IV contrast is most appropriate initial imaging for older adults with back pain 3
• Patients with prior spinal surgery require early imaging regardless of symptom duration 1

Critical Pitfalls to Avoid

• Do not delay imaging if myelopathy signs emerge at any point during treatment 3, 2
• Do not assume radiographs rule out fracture; MRI may be needed even with negative plain films 3
• Do not order imaging during initial 4-week period unless red flags develop 5, 2
• Single red flags have low diagnostic accuracy; combination of multiple red flags increases probability of identifying serious pathologies 4
• False-positive rates with single diagnostic blocks are high (63% cervical, 55% thoracic, 27% lumbar), requiring controlled comparative blocks for accurate diagnosis 6