(Kiosk 1) Segmental Zoster Paresis of the Upper Extremity: A Case Report

Case Diagnosis: 45-year-old male with segmental zoster paresis (SZP)

Case Description: A 45-year-old male with herpes zoster (HZ) at right C5/C6 dermatomes presented with right upper extremity (RUE) paralysis weeks after onset of rash. He had 0/5 right shoulder abduction and flexion; diminished lateral shoulder sensation, deltoid atrophy, and absent biceps and brachioradialis reflexes. Over the course of several months, he was seen by orthopedics, neurology, physiatry, and neurosurgery and differential diagnoses included axillary nerve injury, neuropathy, C5-6 radiculopathy, brachial plexopathy, and segmental zoster paresis. MRI of brachial plexus was normal. MRI cervical re-demonstrated previously known severe degenerative changes at C5-6 and C6-7. Electrodiagnostic studies showed absent right lateral antebrachial sensory nerve and axillary motor nerve responses, and low amplitude suprascapular motor action potential. Electromyography (EMG) demonstrated fibrillation potentials in the deltoid, infraspinatus, triceps, pronator teres, and first dorsal interosseus muscles; and chronic changes in the flexor pollicis longus muscle. Findings were consistent with an upper trunk brachial plexopathy with superimposed chronic C8 radiculopathy. Occupational therapy was prescribed for SZP.

Discussion: SZP is a rare complication that causes focal weakness in 0.5-5% of patients with HZ. It typically starts 2 to 3 weeks after onset of rash in the myotome corresponding to dermatomal distribution. In the majority of patients, it affects the face; < 1% of patients have paresis of the limbs with C5-7 nerves most frequently affected. The pathogenesis of SZP remains uncertain, but literature suggests that it is likely due to inflammation from spread of varicella-zoster virus along the nerve. EMG findings in previous reports demonstrate evidence of denervation in the affected muscles.

Setting: Outpatient Veterans Affairs Hospital

Assessment/Results: After 6 months of rehabilitation, the patient fully regained strength and function in his RUE.

Conclusion: SZP has a generally good prognosis, and patients benefit from therapy. Recognition of this condition can avoid unnecessary procedures and treatments.