A case of segmental zoster paresis: Unusual motor manifestation of varicella zoster virus reactivation

Background. Herpes zoster (HZ), caused by reactivation of varicella-zoster virus (VZV), typically involves sensory nerves. Segmental zoster paresis (SZP) is a rare complication, occurring in 0.5–5% of cases. It is often overlooked due to subtle clinical signs, pain-related guarding, and involvement of regions where weakness is difficult to detect. Case report. A 74-year-old woman developed progressive weakness and pain in her left hand, following vesicular rash in the C7–C8 dermatomes. Neurological examination revealed flaccid paresis without sensory loss progression. MRI of the cervical spine showed no compressive pathology. Electrophysiological studies confirmed multiroot involvement (C5, C7, and C8), consistent with SZP. She was treated with oral antivirals, corticosteroids, pain management, and physical therapy, with gradual improvement over two months. Conclusions. SZP is an uncommon but important differential diagnosis in patients with acute focal weakness after shingles. Prompt recognition supported by electrophysiology can prevent misdiagnosis and facilitate timely treatment.