Anesthesiology APPLIED Exam › Regional anesthesia and acute pain

Epidural hematoma and abscess

Regional anesthesia and acute pain·~5 min read· Physician-reviewed✓ Sourced · 2

Stem

A 71-year-old woman, 68 kg, is on postoperative day 1 after an open right hemicolectomy. A T9–T10 epidural catheter is running bupivacaine 0.1% with hydromorphone. She receives enoxaparin 40 mg once daily; the last dose was 8 hours ago. At 0600 she moved both legs normally. At 1100 the nurse calls: she cannot lift either leg, her thighs are numb, and she has new mid-back pain.

Question

What is going on, and what do you do right now?

Ideal answer

HeadlineEpidural hematoma until proven otherwise, and the clock is running. I go to the bedside myself.

Examine against the morning exam. Motor strength, sensory level, saddle anesthesia, urinary retention: a dilute thoracic infusion should not produce a dense bilateral leg block, so new weakness is a red flag.
Stop the infusion now, because a drug block should regress; I wait only briefly.
Hold tonight's enoxaparin, send platelets and coagulation studies, call surgeon and neurosurgery before the scan, since outcome depends on decompression speed; emergent thoracolumbar MRI.
The catheter stays in for now, because pulling it soon after a dose can itself bleed; out ≥12 hours after the last prophylactic dose; next dose ≥4 hours after removal.¹
Hematoma means laminectomy, ideally within 8 hours of onset, when recovery is far likelier.¹

Watch for: Neurologic checks until the operating room; exact times documented.

Breaking down the answer

Name the diagnosis in the first sentence — new or progressive motor block was the presenting feature in 83% of closed-claims hematomas, while back pain was present in only 25%;¹ waiting for pain is the classic error.
Dilute on purpose — a weak solution is chosen precisely so that a hematoma is not masked.¹ Changes if: the block keeps spreading after the infusion stops, which ends the waiting.
After 24 hours, outcomes are poor — decompression within 8 hours gave the best recoveries, and patients operated after 24 hours mostly did poorly;¹ mobilizing the surgeon in parallel with the MRI saves the hours that matter.
Know the risk factors — older age, female sex, renal impairment, traumatic or repeated puncture, catheter manipulation, and anticoagulation; the historical incidence was under 1 in 150,000 epidurals, but 1 in 3,600 in elderly women after knee arthroplasty.¹
LMWH timing at the catheter — once-daily prophylaxis with a catheter in is acceptable; Changes if: twice-daily, which carries more risk, so the catheter comes out before it starts.¹ The ASRA fifth edition (2025) keeps the same low-dose intervals (neuraxial-anticoagulation-guidelines page).
Keep abscess in the differential — it presents later, over days, with fever and back pain; the scan that diagnoses one also diagnoses the other.

Follow-up question

The MRI is normal and the weakness resolves after stopping the infusion. On day 4 she has a temperature of 38.6 °C, worsening back pain, and redness and tenderness at the catheter site, with intact leg strength. What now?

Follow-up answer

HeadlinePossible epidural abscess, urgent though she is intact: the classic triad of back pain, fever and deficit is present in only 7.9% of cases.²

The deficit is the late sign. I tell her and the surgical team what I suspect. I remove the catheter, timed to her enoxaparin, and send the tip and a site swab for culture with two sets of blood cultures, then an emergent gadolinium-enhanced MRI.² After cultures, empirical antibiotics covering Staphylococcus aureus, about two-thirds of cases, with infectious disease and neurosurgery involved.² A collection with any deficit is decompressed as soon as possible;² antibiotics alone are for selected patients without a deficit. I examine her neurologically every few hours.

Pitfalls that cost points

Pulling the catheter immediately while enoxaparin is at peak effect.
Dismissing an abscess because she has no deficit.

Rapid-fire

Q: What is the single most useful protective step for a catheter on a surgical ward? A: A dilute local anesthetic and scheduled neurologic checks, so a new motor block stands out.¹

Q: Which imaging study, and why not CT? A: MRI, because it shows the cord and the epidural space; CT is a fallback only when MRI is unavailable.

Q: Which organism do you cover first in an abscess? A: Staphylococcus aureus, which causes about two-thirds of cases;² I cover MRSA too until cultures return.

Q: Name two host risk factors for an abscess. A: Diabetes, the most consistent one, and IV drug use; spinal trauma is another.²

Q: What changes with twice-daily prophylactic LMWH? A: The catheter is removed before the first dose, because that regimen carries a higher hematoma risk.¹

Numbers to know

Item	Value
Historical hematoma incidence	<1:150,000 epidural; <1:220,000 spinal¹
Elderly women after knee arthroplasty	1:3,600¹
Presenting sign (closed claims)	Motor block 83%, back pain 25%¹
Decompression window	Within 8 h of symptom onset¹
Prophylactic LMWH and catheter	Remove ≥12 h after dose; next dose ≥4 h after removal¹
Abscess classic triad present	7.9%²
S. aureus share of abscesses	About two-thirds²

Sources

1.Regional Anesthesia in the Patient Receiving Antithrombotic or Thrombolytic Therapy: ASRA Evidence-Based Guidelines (Fourth Edition) · ASRA, 2018 · history.mayoclinic.orgSource of incidence, presenting-symptom data, the 8-hour laminectomy window and the LMWH intervals on this page; the fifth edition (2025) summary at guidelinecentral.com could not be fetched this session, so check intervals against it.
2.Spinal epidural abscess · ACP Hospitalist, 2023 · acphospitalist.acponline.orgClassic triad in 7.9%; MSSA about two-thirds; emergent gadolinium MRI; decompression as soon as possible.

Facts on this page were checked against these sources on Oct 15, 2026. Guidelines change; confirm doses against current institutional protocols.