A 71-year-old man presented with an impaired range of motion and pain in his left arm that had progressed for 8 days, accompanied by headaches and neck pain. He recalled a tick bite 1 month earlier. Clinical examination revealed a complete motor palsy of the left arm (0–1/5 in all muscles) and weakened reflexes of the upper and lower limbs (0–1/4). Electrophysiologic examinations showed signs of axonal damage to the radial, ulnar, and median nerves on the left. An MRI examination did not show any acute lesions of the meninges, brain, or spinal cord. The CSF showed lymphocytic pleocytosis and antibodies against tick-borne encephalitis virus (TBEV).1 The CSF and blood samples were negative for borrelia. An MRI of the brachial plexus2 showed bilateral inflammation of trunks and fascicles (Figure). The findings show that TBEV infection may cause plexitis after tick bites.
Figure. MRI of the Brachial Plexus.
(A) Coronal T2-weighted (T2w) fat-suppressed sequence (B) T2w-hyperintense lesions at the level of the fascicles (C) trunks, and (D) roots on the right and (E, F, G) left. (H) Three-dimensional reconstruction of the left brachial plexus in sagittal and (I) lateral views.
Footnotes
Teaching slides: links.lww.com/WNL/C784
Author Contributions
F. Jende: drafting/revision of the article for content, including medical writing for content; major role in the acquisition of data; study concept or design; and analysis or interpretation of data. T. Hilgenfeld: major role in the acquisition of data. A. Juerchott: major role in the acquisition of data. F.T. Kurz: major role in the acquisition of data; analysis or interpretation of data. M. Bendszus: major role in the acquisition of data; study concept or design. M.A. Schoenfeld: drafting/revision of the article for content, including medical writing for content; major role in the acquisition of data. J.M.E. Jende: drafting/revision of the article for content, including medical writing for content; major role in the acquisition of data; study concept or design; and analysis or interpretation of data.
Study Funding
No targeted funding reported.
Disclosure
The authors report no relevant disclosures. Go to Neurology.org/N for full disclosures.
References
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