Brain disease link to Monkeypox found in USA

As the monkeypox outbreak continues to spread around the globe, scientists have said they are seeing the first signs of a rare but potentially serious complication of the virus.

Daniel Pastula, associate professor of neurology and infectious diseases at the University of Colorado School of Medicine and epidemiology at the Colorado School of Public Health, and professor of neurology, Ken Tyler have warned the Centre for Disease Control  they have found two cases of monkeypox-associated encephalomyelitis — inflammation of the brain and spinal cord — in patients in Colorado and Washington, D.C.

Pastula and Tyler first warned of the neuroinvasive potential of monkeypox last month writing that the disease “likely has the potential to be neuroinvasive based on animal models, previous case series, and preliminary reports currently under investigation. Even though neurologic manifestations of human monkeypox virus infection are rare, given the increasing cases throughout the world, neurologists should be prepared to recognise, diagnose, and treat potential neuroinvasive disease or other neurologic symptoms.”

Pastula added: “Historically with monkeypox and its cousin, smallpox, there have been reports of neurologic syndromes associated with them. It’s rare, but they have been described. With the increasing numbers, we were concerned that we might start seeing neurological effects. That’s why Dr Tyler and I wrote the review in early August warning people to be on the lookout for these.

The team saw the first actual cases of encephalomyelitis in the two affected patients days after that paper published in August when they were alerted to the case in Colorado. “We got our neuroinfectious disease group together to help figure out what was going on and worked with the Colorado Department of Public Health and the Environment and CDC. We also learned of a second case in the District of Columbia. The CDC wanted to combine those cases for the report, so my colleagues in the District of Columbia provided information on their case, we provided information on our case, we did a literature review, and then worked on some messaging around that.”

They were two young, presumably healthy, gay men who contracted a systemic monkeypox virus infection. There was no known contact with someone infected with monkeypox that they knew of, but they developed the systemic illness and the characteristic monkeypox rash. In one case five days and the other case nine days later, they developed inflammation of the brain and the spinal cord.

“We don’t know whether it was from the virus getting into the brain and the spinal cord, or whether the systemic infection triggered an autoimmune reaction that caused the immune system to target those regions, but we treated it like it could have been either,” said Pastula. “Both cases were treated with the appropriate antiviral medication, and then, considering there might have been edema or an autoimmune component to this, both were given steroids for a time. We tried them both on IV immunoglobulin, which is an immunomodulatory medication, but it wasn’t successful in making their symptoms better, so we switched after a few weeks to a plasma exchange to remove that ‘inflammatory soup’ that might have been going on.

He added that neurologic syndromes associated with monkeypox virus infections are rare, there are more than 20,000 cases of monkeypox reported in the United States and at present the team have found two who developed encephalomyelitis.

“We’re talking much less than 1% of cases,” he added. “But if you have enough people getting monkeypox, you will see rare cases. The reason we wrote that review and these reports was to make clinicians aware that in people who have monkeypox virus infections, they can sometimes cause a neurologic syndrome. It’s rare, but it that may happen.”