Magnetic resonance imaging in a patient with segmental zoster paresis

Segmental zoster paresis, which is a clinically rare complication of herpes zoster (HZ), typically occurs 2 to 3 weeks after skin eruption and affects the myotome corresponding to the dermatomal distribution of the HZ.1 Inflammation involving anterior horn cells or anterior spinal nerve roots seems responsible for the pathogenesis. However, pathologic data are scarce because of favorable outcome, and there is difficulty in localizing the lesion in zoster-induced weakness.1 Electrodiagnostic studies in patients with focal weakness after HZ indicate that the lesion lies anywhere at the root, plexus, or peripheral nerve.2 Among neurologic complications of HZ, MRI successfully revealed abnormally contrast-enhanced facial nerves in Ramsay Hunt syndrome3 or lesions in the CNS.4 To investigate the site of lesion, we examined the spinal nerve roots in a patient with segmental zoster paresis by gadolinium-enhanced MRI. Case report. A 54-year-old woman had been well until 1 month before admission, when she noticed a tingling sensation on her right groin followed by a skin eruption. The diagnosis of HZ was made, and she was placed on oral acyclovir (2,400 mg a day for 2 weeks and then 1,200 mg a day for 9 days). Two weeks after the onset of HZ she noticed bilateral facial drooping and loss of taste. Next day she developed difficulty in raising her right lower limb. She was referred to our hospital 4 weeks after the onset of HZ. On …