Disclosures: Rebecca Caine, MD: No financial relationships or conflicts of interest

Case Description: The patient presented with right upper extremity pain followed by development of a characteristic vesicular rash in the C4-C5 dermatomes, for which valacyclovir was prescribed. The patient subsequently had acute onset of weakness and was prescribed a methylprednisolone dose pack for presumed brachial neuritis. Strength was graded as 1/5 for shoulder flexion, extension, abduction, external rotation and 3/5 for elbow flexion. Sensation and reflexes were intact. The patient underwent physical therapy and regained near full function 3 months after initial onset of weakness.

Setting: Outpatient office within post acute care center

Patient: A 60-year-old female with past medical history of hyperlipidemia and fibromyalgia Assessment/

Results: Right shoulder MRI was significant for subtle muscle edema signal involving the supraspinatus, infraspinatus and posterior deltoid. Nerve conduction studies were within normal limits. Needle electromyography performed 3 weeks after symptom onset was significant for mild denervation of the deltoid and infraspinatus. Considerations include brachial neuritis followed by mononeuritis multiplex, and the more remote possibility of segmental zoster paresis.

Discussion: The patient’s clinical presentation and MRI findings are most consistent with brachial neuritis. An alternative diagnosis is mononeuritis multiplex of the axillary and suprascapular nerves. While both of these conditions have been described as post infectious processes, only brachial neuritis has a well defined association with herpes zoster virus. Lastly, segmental zoster paresis, a rare and under recognized complication, is believed to be due to direct viral spread from the dorsal root ganglion to the anterior horn cell, ventral root or peripheral nerve resulting in motor impairment. In this case, both the C5 dermatome and myotome are involved.

Conclusion: Despite profound weakness, this electrodiagnostic presentation projected a favorable clinical outcome, highlighting the utility of electrodiagnostic testing in guiding prognostication. Finally, this case is intended to enhance awareness and explore the mechanisms of development of motor paresis following herpes zoster virus infection.

Level of Evidence: Level V

« Back to AAPM&R Annual Assembly 2020

PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/development-of-acute-onset-upper-extremity-motor-paresis-following-outbreak-of-herpes-zoster-rash-a-case-report/