Case Report of Secondary Trigeminal Neuralgia Following Nerve Block-Induced Herpes Zoster Infection

Trigeminal neuralgia (TN) frequently manifests in pain management contexts and may arise secondary to a variety of underlying conditions. Although infections are uncommon etiological factors, there are rare instances where primary TN (PTN) precipitates conditions such as herpes zoster following nerve block interventions. This report discusses a case of secondary TN attributed to herpes zoster post-trigeminal nerve block, initially presenting as PTN. This case aims to enhance the diagnostic and therapeutic approaches of pain management specialists when dealing with such complexities.

A 55-year-old male, evaluated at the Pain Department of Beilun People's Hospital in Ningbo, China, presented with intermittent, electric shock-like pain in the left upper jaw, diagnosed as PTN. Subsequent to a trigeminal nerve block, the patient developed herpetic lesions suggestive of herpes zoster on the left upper lip. Following a confirmed diagnosis of herpes zoster infection, antiviral treatment was administered, significantly alleviating the pain. This transformation from PTN to herpes zoster-induced TN is not only rare but also noteworthy, marking this as the first reported case of herpes zoster induction following a trigeminal nerve block in a TN patient.

Trigeminal nerve block may trigger herpes zoster reactivation within the innervated regions of the trigeminal nerve, potentially impacting its adjacent branches and causing secondary neuropathic pain. This case underscores the need for vigilance in monitoring for viral infections postneurolytic procedures in patients with TN.