Rosen & Barkin's 5-Minute Emergency Medicine Consult (245 page)

• 604.90 Orchitis and epididymitis, unspecified
  
• 604.91 Orchitis and epididymitis in diseases classified elsewhere
  
• 604.99 Other orchitis, epididymitis, and epididymo-orchitis, without mention of abscess
  

BASICS

• A rare pyogenic infection of the spinal epidural space
  
  • 2–25/100,000 admissions
    
• Most common in thoracic spine, followed by lumbar and cervical
  

• Focus of infection is present followed by either hematogenous spread (∼50%) or direct extension
  
  • No focus identified in ∼1/3
    
• Most common source is skin infection:
  
  • Any pyogenic infection may be source
    
• Staphylococcus aureus
  accounts for >50% of cases:
  
  • Many are MRSA
    
  • Streptococcus is 2nd most common
    
• Haemophilus influenzae,
  gram-negative bacilli, mycobacteria, anaerobic, coagulase-negative Staphylococcus, fungal, and mixed infections also occur
  
• Complication of epidural catheter or spinal surgery
  
• Unusual complication of lumbar puncture (usually follows multiple attempts)
  

• Children present similar to adults with back pain, fever, and neurologic signs as well as nonspecific systemic symptoms
  
• Infants may exhibit only fever, irritability, and associated meningitis
  
• Sphincter disturbance is frequently seen
  
• Usually secondary to hematogenous spread
  
• Location and bacteriology similar to adults
  

DIAGNOSIS

• Fever and severe back pain represent “red flag” for potentially serious condition:
  
  • If pain is radicular or there is neurologic disturbance, likelihood of epidural abscess is increased
    
• Classic presentation:
  
  • Severe, progressive back pain (often radicular)
    
  • Fever
    
  • Neurologic deficit:
    
    • Weakness or paralysis
      
    • Sensory level
      
    • Sphincter disturbance
      
    • May present with signs and symptoms of sepsis without prominent back pain
      
• Occurs at all ages including infants:
  
  • Peak is at ages 60–70 yr
    
• Most patients have predisposing condition:
  
  • IV drug abuse (IVDA)
    
  • Diabetes
    
  • Malignancy
    
  • Chronic steroids
    
  • Chronic alcoholism
    
  • Instrumentation or spinal surgery
    
  • Indwelling vascular catheter
    
• May occur in the absence of identifiable predisposing factors
  

• Back pain
  
• Fever
  
• Neurologic deficit:
  
  • Weakness
    
  • Paresthesias
    
  • Incontinence
    

• Fever
  
• Localized spinal tenderness and/or erythema
  
• Neurologic deficit
  
• Evidence of IV drug use or other predisposing factors
  

• History should include predisposing conditions when this diagnosis is suspected
  
• Physical exam for source of infection, localized spinal tenderness, and neurologic findings:
  
  • Decreased sphincter tone
    
  • Saddle anesthesia
    
  • Lower extremity weakness
    
• Postvoid residual or sonography
  
• Younger adults should have <50 mL postvoid residual urine:
  
  • Older adults may have residual of 100 mL
    
• Erythrocyte sedimentation rate (ESR) as below
  
• MRI with and without gadolinium contrast is the diagnostic test of choice:
  
  • CT with IV contrast or myelography if MR not available
    
  • Suspected epidural abscess is an emergency and requires emergent imaging
    

• ESR is almost always elevated (∼100%), but is nonspecific:
  
  • Normal ESR makes diagnosis much less likely
    
• C-reactive protein nearly always elevated
  
• Blood cultures often positive (∼60%)
  
• Leukocytosis with left shift is common (∼70%)
  
• CSF often abnormal, but nondiagnostic; routine lumbar puncture should be avoided when epidural abscess is primarily suspected (may cause meningitis)
  

• MRI is at least 90% sensitive:
  
  • Shows high-intensity lesion on T2 imaging
    
• CT with IV contrast if MR or myelography not available
  
• Myelography and CT myelography are also sensitive, but risk dissemination
  
• Plain films are often abnormal but nonspecific
  

• Diagnosis is difficult owing to rarity of condition and nonspecific symptoms:
  
  • Multiple physician encounters commonly precede diagnosis
    
  • Most common initial diagnosis is benign musculoskeletal pathology: Muscular or ligamentous pain, degenerative arthritis, compression fracture, discogenic pain
    
• Back pain with fever, systemic signs, and symptoms:
  
  • Vertebral osteomyelitis
    
  • Spinal tumor (usually there is a known primary)
    
  • Meningitis (cervical epidural abscess may mimic, but bacterial meningitis usually associated with abnormal mental status)
    
  • Discitis (usually postinstrumentation)
    
  • Pyelonephritis
    
• Back pain with neurologic signs and symptoms:
  
  • Cord compression
    
  • Cord ischemia
    
  • Disc herniation
    

Fever and back pain should be urgently investigated with MRI when epidural abscess is suspected

TREATMENT

Spinal immobilization if trauma suspected or other cause of fracture suspected

Broad-spectrum parenteral antibiotics early

• Must include coverage for
  S. aureus,
  Streptococci, and gram-negative rods
  
• Vancomycin (for possible MRSA) and a 3rd-generation cephalosporin (for gram-negative coverage) are appropriate initial antibiotics
  
• Cover Pseudomonas if IVDA
  
• 1 suggested regimen includes vancomycin, ceftazidime, and metronidazole (for anaerobes)
  

• Urgent imaging essential when diagnosis is considered
  
• Delay in treatment is associated with poorer outcome
  
• If unable to localize lesion on physical exam, consider imaging entire spine
  
• Urgent neurosurgical consultation or transfer for definitive therapy (surgical decompression) after diagnosis and antibiotic administration:
  
  • Conservative treatment (prolonged [6 wk] antibiotic therapy) may be successful
    

• Ceftazidime: 2 g (peds: 50 mg/kg)
  
• Vancomycin: 15 mg/kg IV loading dose (peds: 10–15 mg/kg q6–8h) q12h
  
• Metronidazole: 500 mg IV
  

• Ceftazidime
  
• Vancomycin
  
• Metronidazole if anaerobes suspected
  

FOLLOW-UP

Patients with epidural abscess should be admitted; MRI is needed emergently; transfer patient if necessary

Patients with definite or strongly suspected epidural abscess should not be discharged

Patients with spinal epidural abscess require admission to facility with neurosurgical capability:

• Transfer usually indicated if a neurosurgeon or MRI is unavailable:
  
  • Administer antibiotics and obtain blood cultures (positive in ∼60%) prior to antibiotics unless this results in a delay
    

• Successfully treated epidural abscess may reoccur, especially in the setting of decreased immunity
  
• Patients with Staphylococcal bacteremia and back pain or neurologic signs/symptoms should be investigated for epidural abscess
  
• Failure to order images that include the involved area:
  
  • Careful physical exam for areas of spinal tenderness and level of neurologic deficit may help avoid this pitfall:
    
    • Consider both thoracic and lumbar imaging for a problem suspected in the mid back and cervical and thoracic imaging for upper back and neck pathology
      
    • If unable to localize lesion on physical exam, consider imaging entire spine
      

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