What history, physical examination findings, red‑flag signs, investigations, and treatment options should be considered for a patient presenting with low back pain?

Evaluation and Management of Back Pain

Initial Assessment and Red Flag Screening

Conduct a focused history and physical examination to categorize patients into one of three groups: nonspecific low back pain (85% of cases), radiculopathy/spinal stenosis, or back pain with serious underlying pathology—this classification determines all subsequent management decisions. 1

Critical Red Flags Requiring Immediate Imaging and Intervention

• Cauda equina syndrome: Urinary retention (90% sensitivity), fecal incontinence, saddle anesthesia, or loss of anal sphincter tone—this is a surgical emergency 1, 2
• Malignancy indicators: History of cancer (increases probability from 0.7% to 9%), unexplained weight loss, age >50 years, or failure to improve after 1 month 1, 3
• Spinal infection: Fever, recent infection, intravenous drug use, or immunocompromised status 1, 3
• Severe neurologic deficits: Rapidly progressive motor deficits at multiple levels, significant trauma relative to age, or major sensory loss 1, 2

History Taking Specifics

• Pain characteristics: Document onset, location, duration, quality, intensity, and whether symptoms worsen with specific positions (sitting, standing transitions) 4, 5
• Radicular symptoms: Ask about leg pain following dermatomal distribution—90% of symptomatic disc herniations occur at L4/L5 or L5/S1 levels 1, 3
• Spinal stenosis pattern: Neurogenic claudication with leg pain/weakness on walking that improves with sitting or spinal flexion (pseudoclaudication) 1, 3
• Ankylosing spondylitis features: Morning stiffness, improvement with exercise, alternating buttock pain, awakening during second half of night, younger age 1

Physical Examination Components

Perform a targeted neurological examination including:

• Straight-leg-raise test: Positive if sciatica reproduces between 30-70 degrees of elevation—fairly high sensitivity for herniated disc 1
• Motor strength testing: Knee extension (L4), great toe/foot dorsiflexion (L5), foot plantarflexion (S1) 1, 6
• Reflex examination: Patellar reflex (L4), Achilles reflex (S1) 1, 6
• Sensory testing: Map dermatomal distribution to identify specific nerve root involvement 6
• Rectal examination: Assess anal sphincter tone and coccygeal mobility when indicated 4

Psychosocial Risk Factor Assessment (Yellow Flags)

Evaluate for depression, anxiety, passive coping strategies, and job dissatisfaction—these predict chronicity and disability more strongly than physical findings. 1, 6, 5

• Depression and somatization predict delayed recovery 6
• Job dissatisfaction predicts chronic disability 6
• Consider cognitive behavioral therapy for high psychosocial risk patients 6, 5

Imaging Decision Algorithm

Do NOT Image

Do not routinely obtain imaging for nonspecific low back pain without red flags—this exposes patients to unnecessary radiation and frequently identifies incidental findings leading to unnecessary interventions. 1, 6

Immediate MRI Indicated

• Any red flag symptoms present 1, 3
• Severe or progressive neurologic deficits 1
• Suspected cauda equina syndrome 1, 6
• Persistent symptoms (>4-6 weeks) with radiculopathy in surgical candidates 1

Imaging Modality Selection

• MRI preferred over CT: Better soft tissue visualization, no radiation exposure, superior for nerve roots and spinal canal 1, 6
• Plain radiographs: Standard initial imaging for pediatric back pain with red flags (9-22% diagnostic yield) 1
• Bone scan with SPECT/CT: Consider for suspected spondylolysis or osseous neoplasms when radiographs inadequate 1

Management Based on Classification

Nonspecific Low Back Pain (85% of cases)

Provide evidence-based reassurance about favorable prognosis, advise remaining active, and avoid bed rest—most symptoms resolve within 4-6 weeks without specific intervention. 1, 6, 2

First-Line Pharmacologic Treatment

• NSAIDs or acetaminophen: Initial medication options with proven benefit 1, 5
• Muscle relaxants: Can reduce pain and improve function 1, 7
• Avoid: Long-term opioids, benzodiazepines (insufficient evidence) 5

Nonpharmacologic Interventions

• Spinal manipulation: Proven benefit for acute low back pain 1
• Exercise therapy: McKenzie method and spine stabilization exercises decrease recurrent pain 1, 2, 7
• For chronic/subacute pain: Intensive interdisciplinary rehabilitation, acupuncture, massage therapy, yoga, cognitive-behavioral therapy, or progressive relaxation 1

Radiculopathy Pattern

• Conservative management first 4-6 weeks: Continue activity, NSAIDs, consider physical therapy 1, 5
• Epidural steroid injections: Only for short-term symptom relief in persistent radicular pain, not recommended routinely 1, 5
• Surgery evaluation: Only for persistent functional disabilities with progressive deficits or failure of conservative therapy 1, 5

Specific Pathology Management

• Compression fracture: Specific treatment for osteoporotic fractures 1, 3
• Ankylosing spondylitis: Specific disease-modifying treatments available 1
• Infection/malignancy: Urgent referral and targeted therapy 1, 3

Follow-Up Strategy

• Reevaluate within 1 month if symptoms persist or worsen 6, 5
• Earlier reassessment warranted for severe symptoms, progressive deficits, or new red flags 6
• Lower threshold for imaging in elderly patients (>65-70 years) due to higher prevalence of serious pathology 6

Critical Pitfalls to Avoid

• Missing cauda equina syndrome leads to permanent disability—always assess for urinary retention 1, 3, 2
• Delaying imaging when red flags present results in poor outcomes 3
• Over-imaging nonspecific low back pain causes unnecessary procedures and costs 1, 6, 3
• Attributing pain to imaging findings without clinical correlation leads to misdiagnosis—morphologic variations may be incidental 4, 3
• Ignoring psychosocial yellow flags misses the strongest predictors of chronicity 6, 3, 5