Clinical, electrophysiologic, and imaging features of zoster-associated limb paresis

Introduction: Paresis is a long-recognized complication of herpes zoster, but there has been comparatively little study of zoster-associated limb paresis (ZALP). Methods: In this study we reviewed 49 Mayo Clinic patients with ZALP. Results: The mean age of onset was 71 years, 67% were men, and the lower limb was affected in 55%. The mean weakness score was 2.0 (0=normal strength, 4=plegia). Most patients developed postherpetic neuralgia (PHN, 92% at 1 month and 65% at 3 months), and the average minimum duration of weakness was 193 days. ZALP was caused by radiculopathy (37%), plexopathy (41%), mononeuropathy (14%), and radiculoplexus neuropathy (8%). MRI demonstrated nerve enlargement, T2 signal prolongation, or enhancement in a majority (64%) of affected plexi and peripheral nerves. Conclusions: ZALP is associated with considerable weakness. It typically lasts at least several months, localizes to plexus or peripheral nerve in 63%, and is associated with high rates of PHN.