Acute herpes zoster radiculopathy mimicking cervical radiculopathy after ChAdOx1 nCoV-19/AZD1222 vaccination

This case report describes an 84-year-old man who presented with 3 weeks of gradually worsening right arm weakness associated with a painful vesicular rash across his arm. This occurred 3 days after his first dose of the ChAdOx1 nCoV-19/AZD1222 (University of Oxford, AstraZeneca and the Serum Institute of India) vaccine. The diagnosis was complicated by the presence of right C5-C6 foraminal stenosis compressing on the C6 nerve root sheath on non-contrast MRI, leading to an initial diagnosis of cervical radiculopathy. However, a positive varicella zoster virus-PCR test and findings of abnormal contrast enhancement of his right C5-C7 nerve roots on gadolinium-enhanced MRI resulted in a revision of his diagnosis to zoster radiculopathy. He was subsequently commenced on oral valacilovir and made significant recovery. This report aims to highlight the diagnostic dilemma between cervical radiculopathy secondary to spondylosis and zoster radiculopathy and how an erroneous diagnosis could result in inappropriate, aggressive surgical intervention and delayed treatment with antiviral therapy.