Epidural abscess medical therapy

Epidural abscess is generally a medical emergency and requires prompt treatment. The treatment of epidural abscess generally involves a combined medical and surgical approach. Antimicrobial therapy for intracranial epidural abscess includes metronidazole, a third generation cephalosporin, and either penicillin or vancomycin. Antimicrobial therapy for spinal epidural abscess includes vancomycin, cefepime, ceftazidime, and meropenem.

The treatment of epidural abscess generally involves a combined medical and surgical approach. Therapy of epidural abscess, either intracranial or spinal, should begin with a combination of surgical drainage and prolonged systemic antibiotics (6-12 weeks, IV followed by PO).^[1] Due to the importance of preoperative neurologic status, along with the unpredictable progression of neurologic impairment, the following procedures should occur as early as possible out of concern for the neurological outcome of the patient:^[2][3]

• Intracranial epidural abscess
  • Burr hole placement
  • Craniotomy
• Spinal epidural abscess
  • Decompressinve laminectomy
  • Debridement of infected tissues

However, in certain clinical scenarios, medical therapy may be the only treatment indicated for that particular case, these include:

• Decompressive laminectomy declined by the patient
• High operative risk
• Paralysis which is unlikely reversible, due to being present for > 24 to 36 hours
• Panspinal infection

In rare cases, patients presenting with minor weakness and no neurologic deficit related to the abscess have recovered without surgical treatment, exclusively following antimicrobial therapy.^[4] The conservative approach in treating epidural abscess includes:

• Antimicrobial therapy
• Close neurologic monitoring strategy, defined before treatment initiation
• Follow-up MRI to evaluate the status of the abscess and confirm its resolution
• Immediate neurosurgery in cases of neurologic deterioration

The indication for a specific antibiotic should be determined by the results of blood cultures or a CT-guided aspiration of the abscess. However, until blood culture results are obtained, the patient should be on empirical antibiotic therapy. The efficacy of the antibiotic treatment, as well as its duration, may be determined by monitoring the evolution of the erythrocyte sedimentation rate, C-reactive protein, and pain, while monitoring for radiographic changes.^[1]

The empiric antibiotic therapy for this type of abscess is similar to the one used for subdural empyema and should be continued for 3 to 6 weeks following surgery, or longer in case of osteomyelitis.^[5] This includes medical therapies against:^[2]

• Staphylococci
• Streptococci
• Gram negative bacilli

This regimen must include:^[1][6]

• Penicillin with anti-staphylococcal activity
• Vancomycin (if MRSA is suspected)
• Third-generation cephalosporin
• Metronidazole

Initial antibiotic therapy for spinal epidural abscess should target:

• Staphylococci
• Aerobic Gram negative bacilli (particularly in patients with history of IV drug use or spinal procedures)

The treatment should last for 4-6 weeks, or longer (8 weeks maximum), to prevent osteomyelitis.^[5] The empirical antibiotic regimens for intracranial epidural abscess may also be applied to spinal epidural abscess.

• 1. Spinal epidural abscess^{[7][8][9][10]}

• 1.1 Empiric antimicrobial therapy

• Preferred regimen: Vancomycin loading dose 25–30 mg/kg IV followed by 15–20 mg/kg IV q8–12h for 2–4 weeks, then PO to complete 6–8 weeks AND Ceftriaxone 2 g IV q24h for 2–4 weeks, then PO to complete 6–8 weeks
• Note (1): Decompressive laminectomy in conjunction with long-term antibiotic therapy tailored to culture results is required.
• Note (2): For critically ill patients, a loading dose of Vancomycin 20–25 mg/kg may be considered.

• 1.2 Pathogen-directed antimicrobial therapy

• 1.2.1 Penicillin-susceptible Staphylococcus aureus or Streptococcus

• Preferred regimen: Penicillin G 4 MU IV q4h for 2–4 weeks THEN PO to complete 6–8 weeks

• 1.2.2 Methicillin-susceptible Staphylococcus aureus or Streptococcus

• Preferred regimen (1): Cefazolin 2 g IV q8h for 2–4 weeks THEN PO to complete 6–8 weeks

• Preferred regimen (2): Nafcillin 2 g IV q4h for 2–4 weeks THEN PO to complete 6–8 weeks

• Preferred regimen (3): Oxacillin 2 g IV q4h for 2–4 weeks THEN PO to complete 6–8 weeks
• Alternative regimen: Clindamycin 600 mg IV q6h for 2–4 weeks, then PO to complete 6–8 weeks

• 1.2.3 Methicillin-resistant Staphylococcus aureus (MRSA)

• Preferred regimen: Vancomycin loading dose 25–30 mg/kg IV followed by 15–20 mg/kg IV q8–12h for 2–4 weeks, then PO to complete 6–8 weeks
• Alternative regimen: Linezolid 600 mg PO/IV q12h for 4–6 weeks OR TMP-SMX 5 mg/kg/dose PO/IV q8–12h for 4–6 weeks
• Pediatric dose: Vancomycin 15 mg/kg/dose IV q6h OR Linezolid 10 mg/kg/dose PO/IV q8h
• Note: Consider the addition of Rifampin 600 mg qd or 300–450 mg bid to Vancomycin in adult patients.

• 1.2.4 Streptococcus

• Preferred regimen (1): Penicillin G 3–4 MU IV q4h for 2–4 weeks THEN PO to complete 6–8 weeks

• Preferred regimen (2): Ampicillin 2 g IV q4h for 2–4 weeks THEN PO to complete 6–8 weeks

• 1.2.5 Enterococcus

• Preferred regimen (1): Penicillin G 3–4 MU IV q4h for 2–4 weeks THEN PO to complete 6–8 weeks

• Preferred regimen (2): Ampicillin 2 g IV q4h for 2–4 weeks THEN PO to complete 6–8 weeks

• 1.2.6 Enterobacteriaceae

• Preferred regimen (1): Ceftriaxone 1–2 g IV q12h for 2–4 weeks THEN PO to complete 6–8 weeks

• Preferred regimen (2): Cefotaxime 2 g IV q6–8h for 2–4 weeks THEN PO to complete 6–8 weeks

• 1.2.7 Gram-negative bacteria

• Preferred regimen (1): Ceftazidime 2 g IV q8h for 2–4 weeks THEN PO to complete 6–8 weeks

• Preferred regimen (2): Cefepime 2 g IV q12h for 2–4 weeks THEN PO to complete 6–8 weeks
• Alternative regimen (1): Ciprofloxacin 400 mg IV q12h for 2–4 weeks THEN PO to complete 6–8 weeks

• Alternative regimen (2): Levofloxacin 750 mg IV q24h for 2–4 weeks THEN PO to complete 6–8 weeks

• Alternative regimen (3): Moxifloxacin 400 mg IV q24h for 2–4 weeks THEN PO to complete 6–8 weeks

• 1.2.8 Anaerobes

• Preferred regimen: Metronidazole 500 mg IV q6h for 2–4 weeks THEN PO to complete 6–8 weeks

• 1.2.9 Staphylococcus, Gram-negative bacteria, and anaerobes (mixed infection)

• Preferred regimen (1): Ampicillin-Sulbactam 3 g IV q6h for 2–4 weeks THEN PO to complete 6–8 weeks

• Preferred regimen (2): Ticarcillin-Clavulanate 3.1 g IV q4h for 2–4 weeks THEN PO to complete 6–8 weeks

• Preferred regimen (3): Piperacillin-Tazobactam 3.375 g IV q4–6h for 2–4 weeks THEN PO to complete 6–8 weeks
• Alternative regimen (1): Imipenem 500–1000 mg IV q6h for 2–4 weeks THEN PO to complete 6–8 weeks

• Alternative regimen (2): Meropenem 1–2 g IV q8h for 2–4 weeks THEN PO to complete 6–8 weeks