Spinal Epidural Abscess (SEA)

View Key Images

Diagnosis Definition

Spinal epidural abscess (SEA) is an infection of the epidural space, located between the spinal dura mater and the vertebral periosteum
Diabetes and intravenous drug use are the most significant risk factors for SEA
Symptomatic patients most commonly present with back pain, fever, and severe focal tenderness
SEA most often results from 1) hematogenous dissemination of microbes from a remote infection, 2) contiguous spread of infection, such as from adjacent vertebral discitis-osteomyelitis (VDO), or 3) direct inoculation, such as from penetrating trauma, discography/biopsy/other surgical procedures, and spinal anesthesia

Imaging Findings

MRI is 91% – 100% sensitive for SEA, most often showing a soft tissue mass with tapering edges in the spinal epidural space with mass effect on the thecal sac and spinal cord
SEA appears isointense to the spinal cord on T1-weighted images and hyperintense to cord on T2/ STIR scans
Postcontrast enhancement can be thin and peripheral, heterogeneous, or diffuse and smooth
Bright signal on diffusion-weighted imaging (DWI), confirmed by low values on apparent diffusion coefficient (ADC) mapping within the abscess represents abnormal restricted diffusion, a feature of SEA
A low signal area on T1 that is high signal on T2 and shows no central area of enhancement is consistent with a liquid abscess that is amenable to surgical drainage

Pearls

SEA can appear similar to a phlegmon; the distinction is critical as SEA often requires surgical treatment
Paralysis, which can result from spinal compression or ischemia secondary to septic thrombosis, requires urgent intervention
Differential diagnostic considerations include vertebral metastases (with extradural extension), epidural hematoma, extruded or migrated lumbar disc, and postoperative spinal seroma

References

Laur O, Mandell JC, Titelbaum DS, Cho C, Smith SE, Khurana B. Acute nontraumatic back pain: infections and mimics. RadioGraphics. 2019; 39(1): 287-288
Reihsaus E, Waldbaur H, Seeling W. Spinal epidural abscess: a meta-analysis of 915 patients. Neurosurg Rev. 2001; 23(4):175-204

Case-based learning.
Perfected.

Try MRI Online Premium for free.

Mastery Series video courses

High-yield cases

Expert case reviews

CME & SA-CME credits

Learn from world renowned radiologists anytime,
actice on real, high-yield cases with MRI Online Premium.

Learn from world renowned
radiologistsanytime, anywhere and practice on real, high-yield cases with MRI Online Premium.