Medical Care
Spinal epidural abscess
A combined medical-surgical approach, with emergent surgical decompression and drainage of purulent material, has been the standard approach to spinal epidural abscess. Antibiotic-based therapy, sometimes combined with CT-directed needle aspiration, has traditionally been used only in patients who are at prohibitively high risk of surgery or who have a fixed paralysis that lasts more than 48-72 hours and that is presumed to be irreversible.
In recent decades, wider use of antibiotic-based, nonsurgical therapy for spinal epidural abscess has been advocated, [24, 25, 26] condemned, [27, 28] and cautiously discussed. [29, 30, 31, 32, 33] The current literature on the subject consists largely of small case series and is inadequate to resolve the controversy. [1, 2, 34] Various prediction criteria advocated to predict failure of medical management [32, 33] have been published, but their value has been questioned. [35]
If medical therapy is to be used as initial therapy for spinal epidural abscess and surgery held in reserve, several caveats apply, as follows:
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A culture-proven microbiological diagnosis should be available (from blood culture or aspiration). MRSA seems to be associated with higher failure rates than MSSA; be extremely cautious when contemplating medical therapy for MRSA epidural infections. [38]
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Stringent follow-up by both the primary team and neurosurgeons must be available and emergent surgery available, if needed.
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The physicians caring for the patient must be aware that rapid deterioration may occur at any time (the first 72 hours being most risky) and that even prompt rescue surgery may leave the patient with a neurological deficit that might have been avoided with surgery at first diagnosis. Failure rates with medical management in one recent study were 41%, with some these failures termed "catastrophic". [33] Other studies have found failure rates of 17%-38%. Cavalier follow-up of medically managed patients with epidural abscess can be disastrous; repeat MRI scanning and/or surgical re-evaluation must be available and performed on an emergent basis when the clinical picture changes.
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Risk factors for failure of medical therapy include any neurological deficit, sensory changes, diabetes, malignancy, bacteremia, age older than 65 years, and MRSA as the causative organism. [32, 33, 39] Patients with multiple risk factors for failure of medical therapy should have the traditional combined medical/surgical approach, with the surgery performed soon after diagnosis.
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A follow-up MRI is necessary within 2-4 weeks to evaluate for improvement with medical therapy.
Empiric antibiotic therapy should include coverage of gram-positive cocci, particularly staphylococci (including MRSA), and gram-negative bacilli. Vancomycin has been the standard agent for gram-positive infections, although linezolid, daptomycin, or ceftaroline could be considered. [40] The third- and fourth-generation cephalosporins and meropenem offer excellent gram-positive (except MRSA) and gram-negative coverage in addition to good CNS penetration.
Pending culture and PCR results, a combination of agents (vancomycin plus cefepime or similar) is needed. Additional coverage may be needed if some of the less-common etiologic agents (see Causes) are suspected. Always tailor coverage once culture data are available; for example, nafcillin, oxacillin, and cefazolin are much better drugs for MSSA infections than vancomycin. Cefazolin is roughly as good as the anti-staphylococcal penicillins for MSSA spinal epidural abscesses. Note that failures due to the development of resistance have occurred when daptomycin alone was used for MRSA spinal epidural abscess. [41] Experience with ceftaroline for these infections is limited, but it may be a useful second-line MRSA agent. [42, 43]
Intracranial epidural abscess
A combined medical-surgical approach is used for intracranial epidural abscess. A craniotomy is usually performed. Empiric antibiotic therapy is similar to that described for spinal epidural abscess; since many of these infections result from prior interventions, the possibility of more-resistant nosocomial organisms must be considered. Vancomycin plus cefepime or meropenem would be good starting choices, with metronidazole added to the cefepime if anaerobes are a major concern. [40]
Surgical Care
Prompt decompression is used to manage intracranial epidural abscess, as it is uniformly considered a neurosurgical emergency.
As discussed in detail above, most patients with spinal epidural abscess require urgent decompressive laminectomy; other surgical techniques may be preferred in certain situations. [44] Biportal endoscopic spinal surgery has been used in selected cases as an alternative to standard open procedures. [45] In some patients without neurologic deficits, medical therapy might be cautiously attempted, recognizing that disastrous outcomes may ensue from this conservative approach (see Medical Therapy). CT-guided drainage might be helpful in some cases of posterior spinal epidural abscess, but the literature on this is scant.
Consultations
Emergent consultation with a neurosurgeon is mandatory for surgical decompression and drainage of purulent material in patients with intracranial epidural abscess. Emergent surgical intervention is also needed in most patients with spinal epidural abscess, and prompt consultation and tight follow-up are mandatory in those in whom surgery is deferred (see Treatment). Consultation with an infectious disease specialist is strongly recommended for both diagnostic and therapeutic assistance.
Long-Term Monitoring
Follow-up MRI should be obtained if any clinical deterioration is noted in patients with an intracranial epidural abscess or spinal epidural abscess. Follow-up MRI at 2-4 weeks should be performed in patients with spinal epidural abscess undergoing exclusively medical treatment to ensure the abscess has improved. It is unclear whether surgically treated patients with spinal epidural abscess who are doing well require follow-up MRI, as the MRI findings often correlate poorly with the clinical course. [46]
Follow-up with the neurosurgeon is always needed.
Follow-up with an infectious diseases specialist is necessary to monitor ongoing antibiotics.
Further Inpatient Care
Frequent neurologic examination is warranted during the postsurgical recovery period and is especially critical in patients undergoing medical treatment for spinal epidural abscess.
Fever, leukocytosis, or new neurologic deficit necessitates repeated imaging, and further (or initial) emergent surgical exploration may be required. [44]
Follow-up MRIs to evaluate spinal epidural abscess in patients who are doing well may not be helpful, as the findings may not correlate well with clinical course. [46]
Physical therapy may be necessary for individuals with a residual neurologic deficit.
Transfer
In the United States, by law, any unstable patient must be stabilized to the extent possible, including consultation and surgery, if indicated, before transfer.
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CT scan showing a lenticular-shaped intracranial epidural abscess.
