Doctors in Canada are struggling to explain a spate of cases involving memory loss, hallucinations and muscle atrophy.
For more than a year public health officials in New Brunswick province have been tracking a “cluster” of 43 cases of suspected neurological disease with no known cause.
A leaked memo from the province’s public health agency asking physicians to be on the lookout for symptoms similar to Creutzfeldt-Jakob disease (CJD), a rare, fatal and largely sporadic disease caused by prion proteins. Symptoms such as memory loss, vision problems and abnormal jerking movements were similar enough to trigger an alert with Canada’s CJD surveillance network. However, it was confirmed that this disease was not CJD.
“We don’t have evidence to suggest it’s a prion disease,” said Dr Alier Marrero, the neurologist leading New Brunswick’s investigation.
Patients initially reported unexplained pains, spasms and behavioural changes, easily misdiagnosed as anxiety or depression.
However, over 18 to 36 months they began to develop cognitive decline, muscle wasting, drooling and teeth chattering. Some also began experiencing frightening hallucinations, including the sensation of crawling insects on their skin.
Each time a possible case arises, a battery of tests is administered to determine if they match the cluster. Cases have risen from only one in 2015 to 24 in 2020, and so far five people are believed to have died from the illness.
“We have not seen over the last 20-plus years a cluster of diagnosis-resistant neurological disease like this one,” said Michael Coulthart, head of Canada’s CJD surveillance network.
The majority of cases are linked a sparsely populated region of the province, with the overall number of cases in the cluster remaining low. However, New Brunswick has a population of fewer than 800 000 people.
Dr Marrero and his team have consulted experts in neurology, environmental health, field epidemiology, zoonotics and toxicology to better understand the possible cause of the mysterious illness.
A growing team of researchers are trying to pin down a common cause or perhaps environmental effect.
“We don’t know what is causing it,” said Dr Marrero. “At this time we only have more patients appearing to have this syndrome.”
Valerie Sim, a researcher of neurodegenerative diseases at the University of Alberta cautioned against jumping to conclusions. “I don’t really know if we even have a defined syndrome. There just isn’t enough information yet,” she said.
She observed that key markers for degenerative neurological illnesses had not been identified, with the cluster’s wide range of symptoms being “atypical” for most brain diseases. Conversely, the scope of symptoms could be explained by certain cancers, dementia or even misdiagnoses.
Frustratingly, when the ailment is unclear a number of tools can be deployed, “and then the patient somehow recovers. You come away never knowing what they actually had,” said Sim.
“We see odd neurological syndromes from time to time. Sometimes we figure them out. Sometimes we don’t.”
Source: The Guardian
