Agree,
The pus only means subcutaneous infection.
Remove epidural, send pus and catheter for culture and sensitivity.
Monitor patient for signs of systemic or epidural infection.
Start on empiric antibiotics to cover gram positive bacteria and adjust that treatment according to culture and sensitivity.
Get ID involved.
Evidence wise - case reports are the predominant source.
The BJA published a review article:
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British Journal of Anaesthesia 2006 96(3):292-302
Main risk factors for epidural abscess (in general, not limited to association with epidural analgesia) were:
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- "Compromised immunity: diabetes mellitus,steroid or other immunosuppressivetherapy, malignancy, pregnancy,HIV infection, alcoholism andcirrhosis.
- Disruption of the spinal column: degenerative disease and disruption by trauma, surgery or instrumentation, including discography, chemonucleosis and central neuraxial block, the latter also providing a direct portal for organisms. Even temporally distant blunt trauma is a risk factor.
- Source of infection: respiratory, urinary and minor soft tissue infections may all act as primary sources of haematogenous spread; i.v. drug abusers are constantly at risk, as are patients with indwelling vascular catheters."
Presentation:
"The early signs and symptoms may be vague, the
‘classic' triad of back pain, fever and variable neurological deficit occurred in only 13% of patients
by the time of diagnosis, and contributed to diagnostic delay in 75%."
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[/SIZE]Clinical features in post anaesthesia epidural infections:
"The history is, as with the ‘spontaneous' lesion,
typically vague with fever, backache and leukocytosis occurring 4 or more days after instrumentation. There
may be evidence of superficial infection at the needle/catheter insertion site, and neurological deficit may or may not be
present."
Infection timing in relationship to neuraxial insertion
"Duration of catheterization: studies quoting a low incidence of epidural infection often relate to catheterization for 2 days or less, but
longer duration has been associated with an incidence of infection of 4.3%, a figure approaching that for intravascular devices. If increases in infection rates with time do approach those for intravascular devices it may be appropriate to extrapolate from data on pulmonary artery catheters where a greater risk of colonization exists after 5 days. Further,
intraventricular devices do not become infected before day 3, with 85% of infections occurring after day 5, lending some support to the widespread practice of removing an epidural catheter by day 4. Figures for intraventricular devices may not be directly relevant, but there can be few indications for such an extended period of epidural block, and re-assessment of the risk/benefit ratio would certainly be wise after 4 days, if not sooner. It has been suggested that the administration set and filter should be changed after 3 days and that the anaesthetist who placed the catheter must take full part in any decision to leave it for longer."
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So - i[/SIZE]f he has back pain, is febrile (no mention so far as to whether he did or didn't) and has neurological symptoms - he gets an MRI (which I hope everyone would agree with). If he has neurological signs, he gets an MRI.
What if he has back pain, no fever and no neurological symptoms? Or fever only?
Given the detrimental outcomes of an epidural abscess, and the fact that a delayed diagnosis may worsen neurological outcomes, I would have a very low threshold for an MRI. It's non-invasive, minimal risk, no radiation. If it's clean - great. If not, then there is your answer, call neurosurg and ID. For this man with superficial infection (who is probably getting something for pain relief that might suppress his normal febrile response and won't mount a normal response to prevent spread of bacterial infection) I would go for the cautious approach and MRI him. Anyway, where I come from I'm fairly certain that as soon as ID got involved, they'd be ordering one anyway, they do love their investigations
🙁
If he does have an epidural abscess, it doesn't
automatically follow that such an abscess was caused by the epidural.
🙂
