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 out-break 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 transmit-ted 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 manifesta-tions of and treatment options for MPXV infections during the current outbreak.

Automated summary

Monkeypox virus (MPXV) is a poxvirus that has spread to 96 countries where monkeypox was not previously reported, with most cases occurring among men who have sex with men. The current outbreak of monkeypox in the United States has shown different symptoms compared to previous outbreaks, with neuroinvasive disease being rare. This report describes two cases of encephalomyelitis in patients with monkeypox during the current U.S. outbreak. It is important to report suspected cases of neurological complications from acute MPXV infection to improve understanding and treatment options during this outbreak.