Is it safe to perform an epidural steroid injection (ESI) in a patient with osteomyelitis?

Epidural Steroid Injection in the Setting of Osteomyelitis

You are correct—active osteomyelitis is an absolute contraindication to epidural steroid injection (ESI), and performing an ESI in this setting risks catastrophic complications including epidural abscess, meningitis, paralysis, and death.

Why This Is Contraindicated

Active infection, particularly vertebral osteomyelitis, represents one of the most serious contraindications to epidural steroid injection. The procedure involves introducing a needle through potentially infected tissue planes and depositing immunosuppressive corticosteroids directly adjacent to or within an infected area 1. This creates multiple mechanisms for disaster:

• Direct inoculation of bacteria into the epidural space during needle passage through infected tissues 2, 3
• Local immunosuppression from corticosteroids that impairs the body's ability to contain existing infection 3, 4
• Hematogenous spread facilitated by the procedure itself and steroid-induced immunosuppression 4

Documented Catastrophic Outcomes

The literature contains multiple case reports of devastating complications when ESI is performed in patients with unrecognized or undertreated spinal infections:

• A 62-year-old patient with no apparent risk factors developed vertebral osteomyelitis of L4-L5 with epidural abscesses after routine lumbar ESI, requiring corpectomy and L1-pelvis fusion, with permanent neurological deficits despite aggressive treatment 2
• A 77-year-old diabetic developed MRSA osteomyelitis of L4-L5 after ESI, presenting initially with only persistent back pain before progressing to soft tissue abscess 3
• Skip-level discitis and osteomyelitis (L2/3 and L4/5) caused by Pseudomonas aeruginosa occurred after caudal epidural injection, demonstrating how infection can spread to distant levels 5
• Aspergillus osteomyelitis with orbital apex syndrome developed after lumbar ESI, likely spreading via Batson's venous plexus 4

Clinical Decision-Making Algorithm

Before any epidural steroid injection, you must actively exclude infection:

Red Flags That Mandate Infection Workup (Not Just Deferral of ESI)

• New or worsening back/neck pain with fever or elevated inflammatory markers (ESR, CRP) 1, 6
• Recent bloodstream infection or bacteremia 6
• Persistent pain at proposed injection site 3
• Constitutional symptoms (night sweats, weight loss, malaise) 1
• Immunocompromised state (diabetes, chronic steroids, HIV) 3, 4
• History of IV drug use 6

Diagnostic Workup When Infection Is Suspected

1. Obtain inflammatory markers (ESR and CRP) before proceeding 1, 6
2. MRI with gadolinium is the imaging modality of choice for detecting vertebral osteomyelitis and epidural soft tissue involvement 1, 7
3. Blood cultures should be obtained if systemic infection is suspected 6
4. Image-guided bone biopsy for culture and histopathology if osteomyelitis is suspected on imaging 1, 7, 8

Absolute Contraindications to ESI

Do not perform ESI if any of the following are present:

• Confirmed or suspected vertebral osteomyelitis 2, 3, 5
• Epidural abscess 1, 2
• Discitis 5
• Active bacteremia or fungemia 6, 4
• Soft tissue infection at or near the injection site 3
• Fever with elevated inflammatory markers and spinal pain 1, 6

Treatment of Osteomyelitis Takes Priority

If osteomyelitis is diagnosed, the focus shifts entirely to infection management:

• Obtain tissue diagnosis via image-guided biopsy or surgical sampling before starting antibiotics when feasible 1, 7
• Pathogen-directed antibiotic therapy for minimum 6 weeks for vertebral osteomyelitis 7, 6
• Surgical consultation for progressive neurologic deficits, spinal instability, epidural abscess, or treatment failure 1, 6
• Monitor response with clinical assessment and inflammatory markers (ESR/CRP) at 4 weeks 1, 6

Common Pitfalls to Avoid

• Never assume back pain is purely mechanical without considering infection, especially in patients with risk factors 6, 3
• Do not perform ESI to "treat" pain in a patient with undiagnosed infection—this can convert a contained infection into a life-threatening emergency 2, 3
• Sterile technique does not eliminate risk in immunocompromised patients who may be colonized with aggressive organisms like MRSA 3
• Persistent pain after ESI warrants urgent evaluation for infectious complications, not repeat injection 2, 3

When Can ESI Be Reconsidered?

Only after osteomyelitis has been successfully treated:

• Completion of full antibiotic course (typically 6-9 weeks) 7, 6
• Clinical improvement with resolution of systemic symptoms 1
• Normalization or significant reduction (>50%) of inflammatory markers 1
• Follow-up imaging showing improvement in soft tissue findings (though bone changes may persist) 1
• At least 6 months of clinical follow-up confirming remission 7

Even then, the risk-benefit ratio must be carefully reconsidered, as the original indication for ESI may have changed after the infectious episode and its treatment.