Abstract
Introduction
Motor complication in immunocompetent individuals with varicella zoster virus (VZV) reactivation is uncommon and may mimic a compressive spinal disorder.
Case Presentation
A 77‐year‐old immunocompetent woman presented with an acute left foot drop preceded by coryzal symptoms and lower back pain. A vesicular rash developed over the left foot one week after the weakness began. Examination showed a predominantly severe left ankle dorsiflexion weakness with reduced sensation over the L5 and S1 dermatomes. A noncontrast magnetic resonance imaging (MRI) of the lumbosacral spine showed noncompressive degenerative changes. Cerebrospinal fluid (CSF) analysis showed lymphocytic pleocytosis, elevated protein, a reduced CSF‐to‐serum glucose ratio, and isolated VZV DNA on the polymerase chain reaction (PCR). VZV DNA was also detected from a vesicle swab. She received 14 days of intravenous acyclovir with neuropathic analgesia. A nerve conduction study and electromyography (NCS/EMG) at three months showed a severe left common peroneal neuropathy with sciatic nerve involvement. There was an initial slow motor recovery with persisting neuropathic pain, but only a residual moderate ankle dorsiflexion weakness remained at 9 months.
Discussion
The combination of preceding radicular pain, vesicular rash, significant leg weakness, and positive VZV DNA in CSF and vesicle specimen supported a diagnosis of VZV‐associated meningoradiculitis. The NCS/EMG was consistent with an evolution of VZV involvement at multiple neuraxial levels into a predominantly peripheral neuropathy. This diagnosis is easily missed when radicular pain precedes or occurs without a rash and when imaging is disproportionate to the severity of deficit. CSF PCR and skin lesion sampling are central to an early diagnosis.
Conclusion
VZV should be considered in patients with acute painful radiculopathy with significant limb weakness that is out of proportion to imaging findings, even without immunosuppression or an early rash. Early antiviral therapy can limit disability, although residual neurological deficits and pain may persist.