epidural_abscess
Table of Contents
epidural abscess
Introduction
- spinal infections such as bacterial vertebral osteomyelitis / discitis or epidural abscess are not only neurologic emergencies for potential acute spinal cord compression, but are life threatening, particularly once infection spreads to the CSF
- this should be considered in ANY patient with midline back pain and fever, especially if they have risk factors such as intravenous drug users (IVDU) or injection drug use (IDU)
- a low index of suspicion is required to detect this condition early
Aetiology
- Spontaneous epidural abscess is rare, accounting for 0.2–1.2 cases per 10 000 hospital admissions per year
- some patients have a pre-existing haematoma from an injury in the preceding weeks which then becomes infected.
- usually are haematogenous spread and seeding in patients with either:
- recent staphylococcal infection within the past few weeks - this may be on the skin or elsewhere
- may spread from bacterial vertebral osteomyelitis / discitis
- most are from haematogenous seeding as for epidural abscesses (see above), but in this case they may be from UTIs or respiratory infections
- discitis occurs in 1-2% of post-op spinal surgery patients in which case they are generally skin flora
- some cases are due to tuberculosis (TB)
- rarely, they may result from direct inoculation of bacterial such as with:
- complication of dry needling or acupuncture of the spine
- complication of central nerve blocks such as epidural blocks or epidural steroid injections 3) 4) 5)
- incidence 1:1000 to 1:100 000
- most patients have risk factors such as compromised immunity, spinal column disruption, source of infection
- risk increases with duration of epidural > 2 days
- even with aseptic technique and 10% povidone iodine skin prep, 18% of the used epidural or spinal needles end up contaminated with bacteria suggesting that there is a risk of inoculation of skin or nasal flora into the epidural space.
Bacteria
- in the developed world, the main bacterial causes are:
- Staph. aureus 57-93% of cases
- streptococcus / streptococcal infections in 18% of cases
- Gram negatives in 13%
- less commonly, and especially in the immunocompromised, a range of other organisms may be the cause, including Listeria monocytogenes / Listeriosis, tuberculosis (TB) and fungi
Clinical presentation
- usually present with progressive midline spine pain
- usually have fever and this is usually the first clinical feature, but fever may also be a late feature
- some may have clinical evidence of acute spinal cord compression, although only around 13% have the classic triad of fever, back pain and new neurology
- some may develop meningism, especially if cervical
DDx
- fever, midline back pain and spinal tenderness:
- spinal tuberculosis (TB)
- vertebral osteomyelitis / discitis and other infections around the spine
- vascular causes
- spinal gout +/- epidural involvement (rare)
Initial Ix of suspected spinal infection
- clinical history and examination, particularly looking for risk factors and for evidence of focal spinal tenderness and neurology
- FBE, U&E, CRP, ESR, 2 sets of blood cultures
- if sepsis is possible based upon clinical features or WCC or raised CRP, then consider emergent MRI scan that day and referral to neurosurgery
- consider empirical broad spectrum antibiotics with staph coverage after discussion with neurosurgery
- definitive management will probably require laminectomy and drainage at a neurosurgical center
- some patients may be medically managed
- if organism not detected on cultures, consider CT guided needle aspirate to determine organism and sensitivities
- all patients usually required many weeks of iv antibiotics
- use of corticosteroids is inconclusive
Complications
- irreversible neurology
- seeding or spread of infection to other sites:
- vertebral osteomyelitis
- endocarditis
- psoas muscle abscess
- meningitis
- severe sepsis
Prognosis
- many factors determine prognostic outcome:
- age - probability of a worse outcome doubles with each decade of age
- degree of thecal sac compression
- duration of symptoms
- severity of sepsis
- presence of neurology (especially if persistent for > 36hrs)
- location - in general, thoracic ones cause more neurology than lumbar ones
epidural_abscess.txt · Last modified: 2020/03/04 04:43 by 127.0.0.1