Imaging Findings in Patients with Zoster-Associated Plexopathy.

Herpes zoster is a reactivation of the latent varicella zoster virus. Among the complications of herpes zoster is zoster-associated limb paresis. The clinical and imaging features of patients with zoster-associated limb paresis due to plexopathies (zoster-associated plexopathy) have had limited description in the literature. The Mayo Clinic patient data base was searched by diagnostic code for patients diagnosed with herpes zoster between January 1, 1996, and September 30, 2012. Patients who met the inclusion criteria for zoster-associated limb paresis or herpes zoster with MRIs obtained were reviewed. Ten patients with zoster-associated plexopathy were identified. Imaging abnormalities were found in 70% of patients. Secondary denervation changes in shoulder girdle muscles and nerve T2 signal hyperintensity were the most frequent abnormalities (50%), followed by nerve enlargement (20%). Enhancement was not evident in any cases despite early imaging in 80% of the cohort. These results demonstrate the clinical utility of MR imaging in confirming the diagnosis of zoster-associated plexopathy.