What is the treatment for spinal phlegmon?

Treatment of Spinal Phlegmon

Spinal phlegmon requires immediate empiric broad-spectrum antimicrobial therapy combined with urgent surgical consultation, as the distinction between phlegmon and abscess may be imprecise and neurological deterioration can occur rapidly. 1

Immediate Management

Diagnostic Workup

• Obtain at least 2 sets of blood cultures before initiating antibiotics to identify the causative pathogen 1
• Measure baseline inflammatory markers (ESR and CRP) to establish a reference for monitoring treatment response 1
• Perform MRI with and without IV contrast to distinguish phlegmon from abscess and assess the full extent of paraspinal and epidural involvement 2
• The addition of IV contrast with fat suppression is invaluable in distinguishing abscess from phlegmon 2

Urgent Consultations

• Obtain immediate neurosurgical or orthopedic spine surgeon evaluation, as phlegmon can progress to abscess or cause neurological compromise 1
• Consult infectious disease specialists at the first sign of serious spinal infection 2

Antimicrobial Therapy

Empiric Treatment (Start Immediately)

Do not delay antibiotics while awaiting culture results 1

• Initiate broad-spectrum coverage immediately upon clinical suspicion 1
• Empiric regimen should include:
  • Anti-staphylococcal agent: Vancomycin if MRSA is a concern (most common pathogen is Staphylococcus aureus at 63.6%) 1, 3
  • Gram-negative coverage: Third or fourth generation cephalosporin or carbapenem 1

Definitive Therapy

• Adjust antimicrobial therapy based on culture results and susceptibility testing 1
• Total duration: Minimum 6 weeks of antimicrobial therapy 1
• Most patients require parenteral antimicrobials for the full course 4

Surgical Decision-Making

Indications for Surgical Intervention

Surgery is indicated if any of the following develop:

• Progressive neurological deficits despite antibiotic therapy 5
• Spinal cord or nerve root compression 5
• Spinal instability 5
• Conversion of phlegmon to abscess on follow-up imaging 1
• Clinical deterioration or treatment failure (persistent fever, pain, or rising inflammatory markers) 1

Medical Management Criteria

Medical management alone may be considered only in highly select patients who meet ALL of the following 6, 3:

• No neurological deficits (most critical factor - incomplete or complete spinal cord deficits predict 99% failure rate) 6
• Age younger than 65 years 6
• No diabetes mellitus 6
• No MRSA infection 6
• Close monitoring capability with ability to proceed urgently to surgery if needed 6, 3

Monitoring Treatment Response

Clinical Assessment

• Monitor pain levels, neurological status, and systemic symptoms continuously during initial treatment 1
• Watch for signs of treatment failure: persistent pain, fever, or neurological deterioration 1

Laboratory Monitoring

• Repeat inflammatory markers (ESR and CRP) after approximately 4 weeks of therapy 1, 5
• Declining inflammatory markers indicate treatment response 1

Imaging Follow-up

• Consider follow-up MRI only if clinical response is poor 5
• Do not misinterpret persistent radiographic abnormalities as treatment failure when clinical improvement is present - imaging changes lag behind clinical improvement 1

Critical Pitfalls to Avoid

• Never delay surgical consultation - even patients with initially stable presentation can develop irreversible neurological damage 1
• Never withhold antibiotics while awaiting cultures - this is explicitly contraindicated 1
• Never rely solely on clinical improvement without monitoring inflammatory markers - this may miss early treatment failure 1
• Never assume phlegmon will remain stable - up to 25.7% of patients initially managed nonoperatively may fail medical management and require surgery 2
• Neurologically intact patients are significantly more likely to succeed with medical management, but close observation is mandatory 3