Infectious Disease Compendium

Epidural Abscess

Diagnosis

Back pain and progressive neurological deterioration, depending on the level of the pain/discitis. Symptoms can be remarkably slow or fast to progress.

Paralysis can occur by mass effect, or, in the case of S. aureus, from vertebral artery/venous thrombosis (PubMed). Why do you think it's other name is coagulase POSITIVE staph? It is most excellent at clotting.

MRI is the diagnostic test of choice, and noncontiguous skip abscesses occur often enough (especially with a source outside the spine) you might as well do the whole spine (PubMed).

Epidemiologic Risks

Post spine surgery and hematogenous. Usually needle users are the biggest risks: IDDM, hemodialysis and IVDA.

Bladder infections spread by way of Batson's (Shazam!) plexus to the LS spine, or so they say. I have seen this multiple times.

And evidently the diagnosis is missed more than half the time at presentation (PubMed). I guess there is a reason it the most common infection to lead to a lawsuit, or so I have been told.

The occasional acupuncture complication (PubMed). But at least their chi was unblocked even as their spinal cord was obstructed.

Microbiology

S. aureus >> streptococci (especially milleri group).

Occasionally anaerobic streptococci and aerobic gram negative rods, predominantly Escherichia coli and Pseudomonas aerugenosa; Tb.

As in all body spaces, any bug can rear its ugly head and cause disease where you do not expect it. That is why you get cultures before antibiotics. If possible. Progressive paralysis takes precedence over purity.

Empiric Therapy

Given all the MRSA in my neck of the woods (i.e. planet earth), I go for the belt and suspenders approach: nafcillin AND vancomycin +/- ceftazadime; surgery emergently if neurological symptoms.

And I kind of wonder about giving something to mess with the coagulase: clindamycin or rifampin. No data. But I wonder.

Specific Therapy

4 to 6 weeks IV as there is almost always concomitant discitis and osteomyelitis.

Pearls

It usually starts as a discitis (but not always) and spreads to the adjacent vertebral bodies and thence into the epidural space.

Occasionally it will present as severe abdominal pain.

S. aureus in the blood and S. aureus in the urine, worry re: epidural abscess in LS spine.

Do all spinal epidurals need surgical intervention if no focal findings? Some data suggests yes, other data suggests not (PubMed) but it is not the highest quality data. Although if they do go on to a neurologic deficit, call risk-management: "The results demonstrated a significant association between time to surgery more than 48 hours and an unfavorable verdict for the provider. The degree of permanent neurologic impairment did not appear to affect the verdicts. Fifty-eight percent of the cases did not present with an initial deficit, including loss of bowel or bladder control. (PubMed)"

High risk for progression/failure of medical therapy are "diabetes mellitus, MRSA infection, neurological impairment involving the spinal cord, acute or progressive motor deficit, CRP > 115 mg/L, WBC count > 12.5 × 109 cells/L, ring-like enhancement on MRI, or bacteremia can be offered nonoperative management with close monitoring as the initial line of treatment (PubMed). "

Rants

They can progress slowly or rapidly, MRI is best diagnostic test. Call a neurosurgeon. Stat. Patient can go to complete paralysis in a surprisingly short period of time.

And do not get one in jail. They might ignore your pain and progressive weakness until you have a complete paralysis, thinking you are malingering. Just saying.

Curious Cases

Relevant links to my Medscape blog

Unexpecting

All that glitters

Less than Perfect

Yet another unexpected pathogen

Reactivation

Siren Call

Pattern Recognition

It happens

Smug

Dry Tap

Last Update: 07/08/18.