Health officials say a bizarre cluster of amnesia cases has been identified in Massachusetts in the past few years, all of them possibly related to opioid, heroin and cocaine use. So far, 14 cases have been identified with there possibly being more out there.
In November 2015, a neurologist in the Boston, Massachusetts area picked up on the pattern and investigated further. He had seen four patients in his practice with amnesia, three who tested positive for opioids (heroin or prescription painkillers) and a fourth with a history of heroin use, reports PBS.
While some memory loss isn’t unusual with drug users, the four patients had acute and complete ischemia of both hippocampi, as identified by magnetic resonance imaging (MRI). These findings were reported to the Massachusetts Department of Public Health (MDPH). A subsequent email sent to relevant medical specialists, including neurologists and emergency physicians, resulted in 10 additional cases being found.
Interestingly, the syndrome seems to target the brain’s memory center, affecting hippocampus neurons on both sides, this in itself, highly unusual says the CDC. The 14 patients were between the ages of 19 to 52 years with a median age of 35. Resolution of the amnesia varied in the group, with one patient having complete resolution of symptoms at five weeks and others still battling memory loss after a year.
What is most concerning is the pattern of blood flow in the cases. “I don’t think anybody really knows how the vasculature can lead to reduced blood flow in the hippocampus, rather specifically and bilaterally,” says Michael Bennett, a neuroscientist at Albert Einstein College of Medicine. He is referring to the fact that the blood vessels in the brain usually start in the center and radiate to the front and back.
And because of the opioid epidemic now going on in the U.S., health officials worry that we will be seeing a lot more cases of this amnesia syndrome in drug overdoses, and it is entirely possible these cases are being caused by synthetic opioids, actually a chemical contaminant, or toxic substance.
The CDC is recommending that broader surveillance is needed to determine whether this represents an emerging syndrome related to substance use or other causes, including the introduction of a toxic substance.
