Two Cases of Monkeypox-Associated Encephalomyelitis - Colorado and the District of Columbia, July-August 2022.

Monkeypox virus (MPXV) is an orthopoxvirus in the Poxviridae family. The current multinational monkeypox outbreak has now spread to 96 countries that have not historically reported monkeypox, with most cases occurring among gay, bisexual, and other men who have sex with men (1,2). The first monkeypox case in the United States associated with this outbreak was identified in May 2022 in Massachusetts (1); monkeypox has now been reported in all 50 states, the District of Columbia (DC), and one U.S. territory. MPXV is transmitted by close contact with infected persons or animals; infection results in a febrile illness followed by a diffuse vesiculopustular rash and lymphadenopathy. However, illness in the MPXV current Clade II outbreak has differed: the febrile prodrome is frequently absent or mild, and the rash often involves genital, anal, or oral regions (3,4). Although neuroinvasive disease has been previously reported with MPXV infection (5,6), it appears to be rare. This report describes two cases of encephalomyelitis in patients with monkeypox disease that occurred during the current U.S. outbreak. Although neurologic complications of acute MPXV infections are rare, suspected cases should be reported to state, tribal, local, or territorial health departments to improve understanding of the range of clinical manifestations of and treatment options for MPXV infections during the current outbreak.
Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Daniel M. Pastula reports receipt of honoraria from the American Academy of Neurology for lectures. Amanda L. Piquet reports institutional support from Genentech, the University of Colorado, and the Rocky Mountain MS Center, royalties from Springer Nature for editorial services, consulting fees from Alexion and Genentech/Roche, honoraria from the American Academy of Neurology for educational lectures and from Medlink for a medical article, payment for expert testimony for the U.S. Department of Health and Human Services National Vaccination Injury Compensation Program from Sands Anderson, PC and from Joe Jones Law Firm, PLLC for medicolegal work, and institutional compensation for participation on a Genentech/Roche data safety monitoring board. J. David Beckham reports grants from the National Institutes of Health, National Institute of Neurological Disorders and Stroke, the National Institute for Allergy and Infectious Diseases, Roche Diagnostics, and VAMerit. Rebecca N. Kumar reports institutional grants or contracts from Regeneron and District of Columbia Department of Health, honoraria from AstraZeneca for a presentation, and a leadership role in the Infectious Disease Community of the International Society for Heart and Lung Transplantation. Princy N. Kumar reports institutional grants or contracts from Lilly, GSK, Merck, Regeneron, Gilead Sciences, Inc., American Gene Technologies, and Biohaven Pharmaceuticals; compensation for participation on Data Safety Monitoring or Advisory Boards for Johnson & Johnson, ViiV Healthcare, Gilead Sciences, Inc., and Theratechnologies, Inc.; and owns stock or stock options in Merck, Johnson & Johnson, GSK, Gilead Sciences, Inc., Pfizer, and Moderna. No other potential conflicts of interest were disclosed.