Family Medicine · Year 3 · from Family Medicine

Case 2: Acute Low Back Pain

Patient Demographics

  • Age: 38 years old
  • Sex: Male
  • Occupation: Warehouse supervisor

Chief Complaint

"I threw out my back 3 days ago lifting boxes, and I can barely move."

History of Present Illness

Mr. Michael Johnson is a 38-year-old man presenting with acute low back pain that began 3 days ago while lifting heavy boxes at work. He felt sudden pain in his lower back with radiation to his right buttock. The pain is described as sharp and aching, rated 8/10, worse with bending, sitting, and transitioning from sitting to standing. He has been lying flat most of the time for relief. He denies leg weakness, numbness, bowel or bladder changes, or saddle anesthesia. He has taken ibuprofen and used a heating pad with minimal relief. No fever or weight loss. No history of trauma beyond the lifting incident.

He had a similar episode 2 years ago that resolved with rest over 2 weeks.

Past Medical History

  • Prior low back strain (2 years ago)
  • No surgeries
  • No chronic medical conditions

Family History

  • Father: Chronic low back pain
  • Mother: Healthy

Social History

  • Non-smoker
  • Social alcohol on weekends
  • Works as warehouse supervisor (heavy lifting, standing)
  • Married, two young children
  • No regular exercise program

Physical Examination

  • Vital Signs: BP 128/78 mmHg, HR 80, Afebrile, BMI 28
  • General: Appears uncomfortable, guarded movements, holds lower back
  • Gait: Slow, antalgic, avoids lumbar flexion
  • Spine:
  • Paravertebral muscle spasm bilateral lower lumbar region
  • Tenderness L4-S1 paravertebral muscles
  • Decreased lumbar flexion (50% of normal) due to pain
  • Extension mildly limited
  • No midline spinous process tenderness
  • No step-off deformity
  • Neurologic:
  • Straight leg raise: Negative bilaterally (no radicular pain)
  • Motor: 5/5 hip flexors, knee extensors, ankle dorsiflexors, great toe extensors bilaterally
  • Sensation: Intact light touch bilateral lower extremities
  • Reflexes: 2+ patellar, 2+ Achilles bilaterally
  • No saddle anesthesia
  • Rectal tone normal (assessed given importance of red flag screening)

Assessment and Diagnosis

  1. Acute mechanical low back pain - Strain/sprain, no red flags identified
  2. No neurologic deficits - Normal neurologic examination
  3. Favorable prognosis - Most acute low back pain resolves within 4-6 weeks

Management Plan

Patient Education (Critical Component):

  • Reassurance: Most low back pain improves significantly within 4-6 weeks
  • Avoid bed rest: Stay active as tolerated, bed rest does not help and may prolong recovery
  • Continue normal activities within pain tolerance
  • Explain lack of red flags and why imaging is not needed

Pharmacologic:

  • NSAIDs: Ibuprofen 600 mg every 8 hours with food x 1-2 weeks (more effective than acetaminophen for acute LBP)
  • Muscle relaxant (short-term): Cyclobenzaprine 10 mg at bedtime x 5-7 days for spasm
  • Avoid opioids for routine acute LBP

Non-Pharmacologic:

  • Ice or heat based on preference (both acceptable)
  • Gentle stretching when acute pain subsides
  • Physical therapy referral if not improving in 2-4 weeks

Work Considerations:

  • Work note for light duty x 1 week (no lifting >10 lbs)
  • Gradual return to full duty
  • Discuss proper lifting mechanics

Red Flags to Return Immediately:

  • New leg weakness or numbness
  • Bowel or bladder dysfunction (incontinence or retention)
  • Saddle anesthesia
  • Fever
  • Worsening pain despite treatment

Follow-Up

  • Return in 2 weeks if not significantly improved
  • Earlier if any red flag symptoms develop
  • Consider imaging and physical therapy if pain persists beyond 4-6 weeks

Teaching Points

  1. Red flags in low back pain (requiring urgent evaluation):
  • Cauda equina syndrome: Saddle anesthesia, bladder dysfunction, bilateral leg weakness
  • Cancer: History of cancer, unexplained weight loss, age >50 or <18, pain at rest
  • Infection: Fever, IV drug use, immunosuppression, recent infection
  • Fracture: Significant trauma, osteoporosis, steroid use
  • Severe/progressive neurologic deficit
  1. Imaging not indicated in acute LBP: Without red flags, imaging (X-ray, MRI) in the first 4-6 weeks does not improve outcomes and may lead to unnecessary intervention. Incidental findings are common and may cause patient anxiety.
  1. Stay active: Bed rest is not recommended and may prolong recovery. Patients should maintain normal activities as tolerated.
  1. Natural history: 90% of acute low back pain resolves within 6 weeks regardless of treatment. The goal is symptom management and functional restoration.
  1. NSAIDs vs. opioids: NSAIDs are first-line and more effective than acetaminophen for acute LBP. Opioids not recommended for routine acute LBP due to lack of superior efficacy and risk of dependence.

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