A 74-year-old woman who presented with a skin eruption involving the left lateral leg along the L5 dermatome and widespread eruptions on the buttocks and trunk was diagnosed with disseminated herpes zoster (HZ). She also had left lower extremity muscle weakness. The pattern of distribution of muscle weakness and gadolinium-enhanced magnetic resonance imaging findings indicated polyradiculoneuritis mainly affecting the L5 spinal root. Moreover, we observed severe weakness of the left tibialis anterior muscle. Weakness of the other L5 myotomes reduced after antiviral treatment; however, left tibialis anterior muscle weakness persisted. We concluded that lumbosacral polyradiculoneuritis was attributable to varicella-zoster virus (VZV) infection, which also caused fibular neuropathy in this case. Retrograde transport of the VZV may have infected the fibular nerve throughout the sites of skin eruption. It is important to be mindful of simultaneous nerve root and peripheral nerve involvement in cases of motor paralysis associated with HZ infection.
Keywords: Varicella-zoster virus; disseminated herpes zoster; fibular neuropathy; polyradiculoneuritis.