A Case of Monkeypox-associated Encephalomyelitis—Colorado, July–August, 2022
Kelli Money1, Markus Hannan4, Elizabeth Kleiner5, Cindy Yuen5, Elizabeth Ferriman5, Elizabeth Matthews1, J. David Beckham2, Lakshmi Chauhan2, Amanda Piquet1, Kenneth Tyler3, Daniel Pastula1
1Neurology, 2Infectious Diseases, 3Neurology & Immunology-Microbiology, University of Colorado School of Medicine, 4Neurology, University of Colorado Health Memorial Hospital, 5University of Colorado Health Memorial Hospital
Objective:
Monkeypox virus (MPXV) disease was declared a public health emergency by the World Health Organization on July 23, 2022, making it imperative for neurologists to be aware of the potential neurologic implications of this outbreak. To aid in educating neurologists, we present a case of encephalomyelitis in the setting of confirmed MPXV infection.  
Background:
MPXV is an orthopox virus in the Poxviridae family, which also includes variola virus (smallpox) and vaccina virus. Prior to May 2022, MPXV was largely confined to Central and Western Africa apart from occasional travel-related cases. However, rapid spread within primarily LGBTQ social networks has created an unexpected pandemic. Occasional reports of encephalitis have been reported in endemic regions with little detail. However, there have been a few reports worldwide of fatal encephalitis in presumed immunocompetent adults in the current pandemic as well as suspected secondary autoimmune encephalomyelitis as reported here. 
Design/Methods:
N/A
Results:
A presumed immunocompetent, healthy, gay man in his 30s developed a febrile illness with a diffuse, itchy, vesiculopapular rash followed by progressive left upper and lower extremity weakness/numbness, urinary retention, headache, and intermittent priapism. CSF demonstrated a lymphocytic pleocytosis with elevated protein. Serum HIV antibody and nucleic acid tests were negative. Serum anti-MOG and AQP-4 antibody tests were negative. MRI brain showed multifocal T2/FLAIR subcortical, caudate, thalamic, splenium, and pontine lesions (some of which were partially enhancing). MRI spine showed a longitudinally-extensive, partially enhancing central cord T2 lesion from the cervical cord to conus. MPXV nucleic acid was confirmed from skin lesions but was not present in CSF. His symptoms gradually improved with oral tecovirimat and immunotherapy for suspected para-infectious autoimmune encephalomyelitis. 
Conclusions:
MPXV can cause central nervous system disease, whether by direct viral invasion or a para-infectious autoimmune process. With prompt recognition and appropriate treatment, recovery can be achieved.  
10.1212/WNL.0000000000203560