Introduction
Herpes zoster is caused by reactivation of varicella zoster virus (VZV) in the dorsal root ganglia. Motor paresis is known to occur in less than 5% of patient with herpes zoster. An inflammatory demyelinating process is suggested as common pathogenesis. We report a case of brachial plexopathy (BPI) with axonal loss related with VZV, which is uncommon, diagnosed by magnetic resonance imaging (MRI) and electomyography (EMG).
Case Report
A 89-year old man who complained pain and skin eruption from posterior neck to left arm was diagnosed as herpes zoster infection at the local clinic. He was treated with famcyclovir 750mg per day. Six days after skin lesion, he complained left arm weakness and came to our hospital. The underlying diseases were well-controlled hypertension and diabetes, and he had no trauma history. On physical examination, motor of left shoulder flexor and abductor was grade 2 by MRC scale, but elbow and wrist motor power was intact. Hypesthesia and neuropathic pain rating as NRS 5 was observed at left C4,5,6 dermatomes. We suspected BPI and MRI showed mild swelling of upper and middle trunk of left brachial plexus. We performed EMG and could confirm upper/middle trunk brachial plexopathy with axonal loss. Steroid pulse therapy (1000mg for 2 hours/day) for BPI was given for 5 days. In course of treatment, patient had urinary tract infection and multi-level pyogenic spondylitis with decline in immunity. Massive antibiotics were needed to treat these infections.
For neurological improvement, physical therapy using nerve electrical stimulation was also applied and the patient had a slight improvement in motor power (shoulder flexor G3, abductor G3), sensation and pain (VAS 2) on the 77th day after symptom onset.
Conclusion
Most of VZV induced BPI is known to be caused by demyelination of neurons. In this case, our patient showed BPI due to axonal loss which is rare. Therefore, we could predict poor prognosis for motor recovery. Acute BPI is commonly treated with steroid pulse therapy, but care must be taken in elderly patients, as it can lead to immunodeficiency and infectious diseases. |
