33. Epidural abscess Flashcards
You are asked to see a patient 5 days post-spinal anaesthesia. The
surgical team is concerned regarding the presence of an epidural abscess.
What are the symptoms and signs of an epidural abscess?
When occur
The classic triad of symptoms and signs are:
Fever
Back pain
Neurological deficit.
However, all three are present in only 13% at presentation. Presentation is
often vague with fever and back pain appearing before neurological deficit.
Some patients may complain of headache. Examination may reveal tenderness -over the spine and neck stiffness.
When would you expect symptoms to start?
Symptoms tend to begin >4 days after central nerve blockade.
What is the incidence of epidural abscess?
Spontaneous epidural abscess is rare, occurring in 0.2–1.2 cases in 10 000
hospital admissions.
The incidence following central nerve blockade is difficult to estimate, but
may be as frequent as 1:1000 or as rare as 1:100 000.
What are the risk factors for developing an epidural abscess?
Compromised immunity: diabetes, immunosuppressant therapy, HIV
infection and liver cirrhosis.
Source of infection: haematological spread from distant sources of infection such as respiratory, soft tissue or urinary tract infection can occur..
Disruption of the spinal column: central nerve blockade and spinal surgery can lead to the introduction of infection from the skin or the accumulation
of haematoma, which may then become infected.
Difficult insertion of central nerve blockade: multiple attempts at insertion
may increase the risk of haematoma formation and lead to breakdown of
aseptic technique.
Disordered clotting: anti-thrombotic and anti-platelet treatments, and
intrinsic coagulopathies may increase the risk of haematoma formation,
which may then become infected.
Prolonged use of central catheters: infection is rare when catheters are used for less than 2 days but may become significant with more prolonged use.
What is the cause of the neurological deficit?
Direct compression of the spinal cord may cause neurological injury, although significant deficit can occur without evidence of compression and deficit is often worse than the degree of compression would suggest.
It has been suggested that leptomeningeal thrombosis or spinal artery compression may result in cord ischaemia.
How would you investigate a suspected epidural abscess?
FBC, ESR and CRP
Raised white cell count occurs in the majority of patients.
Raised ESR occurs more frequently even with early presentation.
Thrombocytopaenia may be present.
MRI has a sensitivity of ∼90%, is non-invasive and is the investigation of
choice.
Cultures: blood culture and pus culture from radiological aspiration may
identify the causative organism.
Causative organism in epidural abscess secondary to
epidural catheter
Staphylococcus aureus
Staphylococcus epidermidis
Pseudomonas aeruginosa
Coagulase-negative Staphylococci
Pyocyaneus
How would you manage an epidural abscess?
abx
ABC: Patients may develop septic shock and require resuscitation.
Antibiotics: Microbiological advice should be sought. Staphylococcal
infections account for the majority of epidural abscesses and therefore
empirical management should be with appropriate agents such as
intravenous flucloxacillin and/or a third-generation cephalosporin. Patients
with known MRSA should be treated with vancomycin or teicoplanin.
Treatment should then be guided by culture results. Intravenous antibiotics
should be continued for at least 3–4 weeks after which oral antibiotics may
be introduced. Antibiotics should be continued for 6–12 weeks
Management surgery
Surgical drainage: posterior or occasionally anterior laminectomy should be
performed early to limit neurological damage.
Percutaneous drainage: radiological percutaneous drainage may be possible
for dorsal abscesses.
Steroids: there is no evidence for the use of corticosteroids to treat an
epidural abscess and the use of steroids in infection is contentious
What is the prognosis?
Mortality rates of 13%–16% are still quoted.
Permanent neurological deficit is
more common in patients developing epidural abscess secondary to central nerve blockade with 62% having permanent deficit. 27% will be left with severe deficit.
Early identification and treatment improves outcome.
Whose responsibility is it to check?
Whose responsibility is it to check?
All surgical and nursing staff caring for patients after central nerve blockade
should be aware of the symptoms of epidural abscess and early referral should
occur. Persistent or increasing motor block should be identified by the
anaesthetist at the post-operative visit or by nursing staff. Bowel or bladder
function disruption is particularly ominous. Some centres have given patients
information at discharge, as symptoms may appear after discharge
