THE MONKEYPOX outbreak continues to spread across the globe. As of 29th August 2022, there were 18,072 confirmed cases reported from 29 European Union (EU) and European Economic Area (EEA) countries. Based on animal models and previous case series, it is known that monkeypox has the potential to be neuroinvasive. According to Daniel Pastula and Kenneth Tyler, both from the University of Colorado School of Medicine, Aurora, USA, neurologists should therefore be prepared to recognise, diagnose, and treat potential neuroinvasive disease as well as other neurologic symptoms.
Although neurological manifestations are rare, Tyler emphasised that current case numbers are orders of magnitude higher compared with past outbreaks. Clearly, this will increase the probability of neurological events occurring.
For example, the Spanish Ministry of Health recently reported fatal cases of neuroinvasive monkeypox in two males aged 31 and 44 years who were diagnosed with encephalitis. The individuals were presumed immunocompetent. Of note, monkeypox virus nucleic acid and anti-orthopoxvirus IgM antibodies were detected in the cerebrospinal fluid of both males.
Tyler also revealed that there have been unpublished discussions of possible transverse myelitis-like disease in people with monkeypox. Further, during the current outbreak, neuropathic pain and pruritis have been reported in areas of rash, for which neurologists might be consulted.
In addition, a meta-analysis based on 1,512 individuals with monkeypox showed that the most common neurological features included non-specific neurological symptoms such as headache (53.8%), with more severe symptoms such as seizure, confusion, and encephalitis occurring rarely (2.7%, 2.4%, and 2.0%, respectively).
Animal models also provide evidence for the neurotropic potential of monkeypox. A survey of tissues from prairie dogs, rats, hamsters, and other pet rodents exposed to monkeypox during the 2003 outbreak in the midwestern USA found amplifiable viral DNA in the brains of approximately 8% of the 52 tested animals.
Given the rarity of the neurologic manifestations of monkeypox, there is little guidance on how to mitigate the risk for neurological effects in people who become infected with the virus. However, it is likely that the implementation and promotion of public health measures that reduce the spread of monkeypox will play an important role.