Segmental Zoster Paresis With Comorbid Carpal Tunnel Syndrome.

This case report involves a 63-year-old male who presented with acute right deltoid weakness following a shingles outbreak in the C6 dermatome, with a chronic history of carpal tunnel syndrome. Notably, the patient had an overuse injury to his shoulder and received a cortisone injection prior to the shingles outbreak. Electrodiagnostic (EDX) testing initially revealed right C6 acute/subacute cervical radiculitis and right severe median neuropathy at the wrist with significant axonal loss. Repeat EDX studies five months following the onset of shoulder paresis showed improved motor recruitment and reinnervation of the C6 lesion, while the median neuropathy findings remain unchanged. This case highlights the diagnostic complexity of concurrent proximal and distal nerve pathologies, often referred to as double crush syndrome, as well as considerations for management and natural history of segmental zoster paresis.