Central Nervous System Infections

Spinal epidural abscesses (SEAs) occur as a result of hematogenous dissemination or from contiguous spread from infected psoas, vertebrae or intervertebral disc spaces. See the table of risk factors below.



Remember, the epidural space contains fat as well as arteries and a venous plexus. SEAs are most common in the thoracolumbar region, where the epidural space is larger and contains more infection-prone fat.

It’s important to recognize and treat SEAs early to prevent serious neurologic complications, but SEAs can be very difficult to diagnose. Symptoms can be mild and nonspecific, like fever and malaise, but can include neurologic symptoms such as bowel/bladder dysfunction, lower extremity weakness, paresthesias and (later) paralysis. If you suspect SEA, obtain two sets of blood cultures and obtain a spine MRI with contrast. If possible, obtain image-guided aspiration and send for cultures prior to starting empiric antibiotic therapy.

Of note, greater than 50% of spinal epidural abscesses are due to Staphylococcus aureus! Other causes include gram negative organisms, Strep spp., anaerobes and rarely, fungi or other atypical pathogens. Because of this, empiric antibiotics should always include MRSA coverage with vancomycin IV (goal trough 15-20) plus either ceftriaxone 2g IV q12 or an anti-Pseudomonal agent such as cefepime or meropenem (if there is concern for Pseudomonas involvement.) There is minimal data on the penetration of pip-tazo (Zosyn) into the CNS, so avoid pip-tazo for CNS infections!

SEAs are treated with a combination of IV antibiotics and surgical drainage (keep in mind that source control—adequate surgical drainage—is key), with an antibiotic duration of 6-8 weeks (or until resolution of abscess on follow-up imaging).

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