A medical mystery: Cluster of patients struck with rare amnesia

Dr. Jed Barash, a neurologist inside Boston area, noticed a pattern between 2012 as well as also 2015. Four patients, mysteriously stricken having a sudden amnesia, had the same rare finding on MRI: A pair of tiny structures deep in their brains, called the hippocampus, was completely knocked out on both sides.

The hippocampus is actually a seahorse-shaped structure of which plays a role in memory as well as also emotion. The patients could remember earlier things, nevertheless they couldn’t make brand-new memories, a phenomenon called anterograde amnesia.

Also peculiar, three of the four patients tested positive for opioids. The fourth, who was not tested, was known to have a history of opioid abuse. The patients, ages 22 to 52, came to the hospital between October 2012 as well as also November 2015.

“We couldn’t definitely address what was causing This particular,” said Dr. Alfred DeMaria Jr., the state epidemiologist for the Massachusetts Department of Public Health. DeMaria was contacted by Barash, who could not be reached for comment, to help investigate the cluster.

Doctors are trying to uncover whether these patients reveal an emerging syndrome related to substance use or whether the idea’s something else altogether.

Picking the brain for clues

The pattern seen on these patients’ MRIs was so rare of which the idea had been described in only a handful of earlier case reports, including a couple of patients with cocaine abuse, one with carbon monoxide poisoning as well as also one patient in France who had inhaled heroin, an opioid.

nevertheless right now faced with the first known cluster of its kind, the Massachusetts Department of Health sent out a statewide alert in February, hoping to keep doctors on the lookout for additional cases.

They found 10 additional patients who had been seen in eastern Massachusetts hospitals between 2012 as well as also 2016, bringing the total to 14. All nevertheless one patient tested positive for opioids or had a history of opioid use. nevertheless none of these cases was fresh, producing the search for a culprit all the more difficult.

“All we had was the medical records,” DeMaria said. “We couldn’t go back (in time).”

Though the MRI findings were described as “ischemic,” meaning there was a lack of blood flow to of which part of the brain, the idea is actually unlikely of which a stroke or lack of oxygen alone would likely cause such a specific as well as also symmetrical injury to the hippocampus, said DeMaria.

“We’re definitely looking for a toxic effect,” he said.

DeMaria wondered whether the spate of brand-new synthetic drugs as well as also unknown contaminants on the illicit market might have something to do with the idea, nevertheless “we don’t even know if the idea’s related to drugs,” he said.

The story of Patient HM

The patients’ anterograde amnesia, along with their hippocampal injuries, reminded DeMaria of a famous lobotomy case through the 1950s: a patient known to most by his initials, HM, who lived most of his life without a hippocampus as well as also suffered a similar, though more severe, anterograde amnesia.

Because the lack of a hippocampus may be similar to having an injured as well as also nonfunctional one, some think of which the Massachusetts cluster can reveal a lot about memory as well as also the brain, as HM did.

“He’s one of the rare anonymous celebrities of which you find inside history of science,” said Luke Dittrich, author of “Patient H.M.: A Story of Memory, Madness, as well as also Family Secrets.”

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When HM was 27 years old, in 1953, he had an experimental lobotomy to cure his severe epilepsy. The neurosurgeon who performed the lobotomy, which removed HM’s hippocampus as well as also additional surrounding structures, was Dittrich’s grandfather.

The surgery cured HM of his epilepsy, nevertheless the idea had a major unintended consequence: He couldn’t form brand-new memories.

“He lived in 30-second increments,” Dittrich said. “The experiences in his life just washed off of him.”

nevertheless his personal tragedy was a boon to science, said Dittrich. Prior to HM, there was no consensus on which parts of the brain might be responsible for creating memories; the idea was widely thought of which the brain worked as a whole to do so.

For over 50 years, memory scientists conducted tests on HM. When he died in 2008, his brain was sent to the University of California, San Diego. the idea was frozen, sliced into 2,401 sections as well as also placed online for the general public to see.

“A lot of what we understand (about) how memory works has been built on top of the seminal studies of which were done with HM,” Dittrich said.

Questions about the brain remain

Another curious aspect of HM’s amnesia, which may not be present inside Massachusetts patients, was of which the idea “bleached away” the narrative of his memories before the surgery, said Dittrich. HM could remember facts about his childhood nevertheless not the stories to go along with them.

“We can all relate to memory loss,” Dittrich said. “nevertheless HM’s amnesia was even more alien to us than we typically imagine the idea to be.”

Barash’s descriptions of the Massachusetts patients did not include similar problems with prior memories, as well as also some even showed improvement months later. The youngest patient, a 19-year-old as well as also the only one without a history of opioid use, no longer had short-term memory loss all 5 months later, though he also developed seizures.

Still, Dittrich wonders what their similarities as well as also differences might unearth about the human brain: why some recovered as well as also some didn’t, whether some have issues with episodic memories inside past as well as also what additional cognitive effects their injuries might reveal.

“the idea’s a terrible tragedy,” Dittrich said, adding of which the Massachusetts patients could nevertheless be “extremely valuable … to memory researchers.”

DeMaria said more research is actually needed to understand what happened as well as also whether the link to opioids is actually more than coincidence. He also hopes doctors in additional states keep an eye out for additional cases of which might be missed. For patients who test positive for opioids, doctors may easily mistake the signs of anterograde amnesia for general intoxication.

“Maybe nobody was looking with This particular,” DeMaria said. “Maybe This particular isn’t brand-new. Maybe the idea was happening all along.”

A medical mystery: Cluster of patients struck with rare amnesia

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