Back Pain - Dr. Carey

Basics

• ~3% of all primary care visits are for lower back pain, the vast majority of which is mechanical or non-specific in origin. 
  
• >90% of low back pain has spontaneous resolution within two weeks regardless of treatment modality. 
  
• Less than 5% have serious pathology.

EM Perspective

• Time-sensitive emergencies = epidural abscess, cauda equina syndrome and vertebral osteomyelitis.

Red Flags
-Trauma
-Unexplained fever
-Immunosuppression/DM/steroid use
-IVDU
-Age >70
-Focal neurologic deficit
-History of spinal instrumentation
-Duration longer than 6 weeks

• Limit imaging to patients with the ‘red flag’ symptoms, MRI is the test of choice.  If MRI is unable to be obtained, CT is the second choice.

• Greater than 90% of disk herniations occur at L4-5 and L5-S1.  Test these motor distributions by examining ankle and great toe dorsiflexion as well as ankle plantarflexion.  Sensory distributions run along the posterior and lateral aspects of the lower extremity.

• 2007 ACP/APS Joint Practice Guidelines recommend NSAIDs as the first line of therapy for acute lower back pain.  Studied regimens were Ibuprofen 400-600mg QID or Naproxen 220-500 mg BID for 2-4 weeks.  Other studies have shown that NSAIDs combined with Skeletal Muscle Relaxants were the most effective regimen with symptom relief at one week.

• The classic triad of back pain, fever, and neurologic deficits only occurs in 13% of spinal epidural abscesses.

• The most common symptom of cauda equina syndrome is urinary RETENTION.  If this pathology is suspected, provide the patient with 10mg Decadron IV prior to MRI scan to prevent progression.

• All pediatric low back pain is ‘red flag’ back pain.  Up to 31% of these patients have a specific diagnosis such as tumors, discitis or malignancy.