Zoster-associated Limb Paralysis: Clinical and Electrophysiological Data of 15 Cases with Segmental Zoster Paresis with the Literature Review

Background: Herpes zoster (HZ) is a viral disease characterized by skin eruptions and pain in specific dermatomes. Focal motor weakness that appears in the segment of skin eruptions is a rare complication of this infection. Because of the difficulty in clinically diagnosing thoracic or upper cervical motor weakness and due to the pain that causes overlooking of weakness, the true incidence of this complication is not known. In this study, we want to review the clinical presentation of segmental zoster paresis and also discuss electrophysiological findings with the involvement of nerve, plexus parts, or spinal roots. Methods: Electromyography records were examined retrospectively from 2010 to 2023 for patients who had HZ-associated limb paresis. Clinical data were reviewed and abstracted, and patients whose clinical limb weakness and sensory deficits conformed to the distribution of peripheral nerve (s) or spinal root and whose electrodiagnostic evaluation corroborated the localization, were included in the series. Results: Fifteen patients were included in our study. Ten of them were men and five of them were women. Paresis and neuropathic pain are the main complaints. In all patients, the distribution of paresis was consistent with the area of skin eruptions. C8-T1 in the upper extremity and L5-S1 in the lower extremity are the most commonly involved segments. Electrophysiological findings showed radicular involvement in three cases, brachial plexus in six cases, ulnar nerve in one case, sciatic nerve in two cases, and fibular nerve in three cases. Axonopathy is the main detected pathology in all cases. Conclusion: Segmental zoster paresis is a rare complication of cutaneous zona zoster and it affects different nerve segments. Clinicians should be aware of clinical and electrophysiological findings of this disease for the appropriate management of the patients.