What are the considerations for a CT-guided nerve root cortisone (corticosteroid) injection in a patient with a history of shingles (herpes zoster) in the left L5 distribution and current L5 nerve root compression?

From the Guidelines

A CT-guided L5 nerve root cortisone injection can be performed in a patient with prior shingles in the same distribution, but it is crucial to proceed with caution and consider the risk of shingles reactivation. The patient's history of shingles in the left L5 distribution two years ago and current L5 nerve root compression with MRI confirmation must be carefully evaluated. Before scheduling the injection, it is essential to confirm the absence of active lesions and consider prophylactic antiviral therapy, such as valacyclovir 1g daily for 3 days, starting the day before the procedure, to prevent reactivation 1.

The standard injection typically includes a long-acting corticosteroid like dexamethasone 4-10mg or triamcinolone 40-80mg, combined with a local anesthetic such as 1-2ml of 0.5% bupivacaine. Patients should be informed that the injection may temporarily increase pain in the affected dermatome due to needle trauma in a sensitized area. Post-procedure monitoring should be more vigilant, watching for signs of infection or unusual neurological symptoms.

Some key considerations for the procedure include:

• The patient's pain may have both mechanical and neuropathic components from the prior shingles, potentially affecting treatment outcomes 1.
• If neuropathic pain is significant, adjunctive medications like gabapentin or pregabalin may be needed alongside the injection therapy for optimal pain control.
• The natural history of lumbar disc herniation with radiculopathy in most patients is for improvement within the first 4 weeks with noninvasive management 1.
• Magnetic resonance imaging (preferred if available) or CT is recommended for evaluating patients with persistent back and leg pain who are potential candidates for invasive interventions.

Overall, the decision to proceed with the CT-guided nerve root cortisone injection should be based on a thorough evaluation of the patient's condition, careful consideration of the potential risks and benefits, and close monitoring post-procedure.

From the FDA Drug Label

• Corticosteroids, including KENALOG-40 and KENALOG-80, may exacerbate systemic fungal infections; therefore, avoid KENALOG-40 and KENALOG-80 use in the presence of such infections unless KENALOG-40 or KENALOG-80 is needed to control drug reactions There is no direct information in the provided drug label regarding the risk of shingles reactivation with corticosteroid use. Key Considerations:

• The label does mention the potential for corticosteroids to exacerbate systemic fungal infections and reactivate other infections such as hepatitis B.
• However, it does not specifically address the risk of reactivating herpes zoster (shingles) with corticosteroid use. Given the lack of direct information, caution is advised when considering a CT-guided nerve root cortisone injection in a patient with a history of shingles in the same distribution as the proposed injection site 2.

From the Research

Considerations for CT-Guided Nerve Root Cortisone Injection

• The patient has a history of shingles in the left L5 distribution and current L5 nerve root compression, which may increase the risk of shingles reactivation after the injection 3.
• However, there is limited evidence on the specific risk of shingles reactivation after CT-guided nerve root cortisone injections, and more research is needed to fully understand this potential complication.
• The safety of CT-guided cervical nerve root corticosteroid injections has been established, with a low rate of minor complications and no major neurovascular complications reported in one study 3.
• In terms of the L5 nerve root compression, studies have shown that it can be caused by various factors, including intervertebral osteophytes 4 and foraminal stenosis 5.
• The use of CT-guided injections may help to accurately target the affected nerve root and reduce the risk of complications, but the potential risk of shingles reactivation should be carefully considered and discussed with the patient.

Potential Risks and Benefits

• The potential benefits of the CT-guided nerve root cortisone injection include relief from pain and inflammation associated with the L5 nerve root compression.
• However, the potential risks, including the risk of shingles reactivation, must be carefully weighed against the potential benefits and alternative treatment options should be considered.
• More research is needed to fully understand the risks and benefits of CT-guided nerve root cortisone injections in patients with a history of shingles, and patients should be closely monitored for any signs of shingles reactivation after the procedure 3, 6.