2 cases of Creutzfeldt-Jakob disease at Moncton Hospital not cause for concern, officials say

Two patients who had cataract surgery at Moncton Hospital this winter were later diagnosed with Creutzfeldt-Jakob disease, a rare and fatal brain disease. 

Horizon Health went on to notify 700 patients they might have been exposed to the medical instruments used.

But New Brunswick health officials say there's no need for concern.

The two cases of Creutzfeldt-Jakob disease (CJD) have been deemed unrelated. The risk of the degenerative brain disease, which leads to a fatal form of dementia, being transmitted through medical instruments is "not significant," given modern sterilization processes, Horizon said in a statement Monday night.

"There are several types of CJD and by far the most common occurs spontaneously with no known cause or triggering event," Dr. Cristin Muecke, the province's deputy chief medical officer of health, said during a news conference in Fredericton on Tuesday afternoon.

Cases caused as a result of medical procedures are "exceedingly rare," accounting for less than one per cent, and there has never been a documented case of transmission during cataract surgery, she said.

Incidence rate of 1 in 1 million

How the Moncton Hospital ended up with two back-to-back cases of CJD, which normally occurs at a rate of only one in a million people, remains unclear.

The Public Health Agency of Canada has been notified and is leading the followup investigation, said Muecke. 

"They determine future followup actions and surveillance."

The agency did not respond to a request for an interview Tuesday.

Few details about the two patients have been revealed, including exactly when or how they were discovered, or their current condition.

But in a video Horizon posted on YouTube Monday night, Dr. Gordon Dow, the chief of infectious diseases at the Moncton Hospital, said the first patient was admitted in December.

The patient, who lives in Moncton, was later diagnosed with CJD by a neurologist.

Dow said the second case of CJD — "completely unrelated" to the first — was identified within six weeks of the first diagnosis.

"Even more unlikely is the fact that both of these patients had undergone cataract surgery weeks before diagnosis of CJD was made," he said. 

"Why would we have two patients occur so soon one after the other in one hospital? When we scrutinized this, we could not find any reason for this except for statistical probability. It just so happens that two rare events occurred at once and these things do happen."

Officials can, however, "very, very solidly say there's no linkage" between the cases, said Dow.

That's because the second patient was showing early signs of CJD before their surgery.

New protocol for medical instruments

After the first case of CJD was discovered, Horizon identified 103 patients who had potentially been exposed to the medical instruments from that case. A cataract surgeon called each of the patients to advise them of the risk, said Dow.

Horizon also mailed the patients and their family doctors a letter on Jan. 15.

An additional 601 patients and their doctors were notified by letter on Feb. 14, after the discovery of the second case.

By having an alert on the patients' charts, doctors will know to watch for any symptoms of CJD, and to screen them for CJD before any they undergo any central nervous system-related operations to ensure there's no risk of contaminating the instruments, said Dow.

Since the letters were sent out, 43 patients have contacted Horizon to learn more about their potential risk. Patients with questions or concerns are encouraged to contact Horizon at 1-844-225-0220.

Dow said some changes have been implemented since the two cases were discovered, based on recommended guidelines.

Patients undergoing cataract surgery are now matched with one of the 16 trays of instruments used and the instruments should never migrate between trays.

"Now that we have that protocol in place, should this ever happen again, instead of 700 and some letters going out, you would just be sending out a letter to a very, very small number of patients who were exposed to those instruments," he said.

'Almost impossible' cases are related

Muecke described the potential risk as "extremely low."

Although she said she could not discuss individual cases, she did say she had spoken to the infection disease physician involved, and based on timelines alone, it's almost impossible that the two cases are related.

"I'm not concerned at this time."

CJD has a very long incubation period, said Muecke.

"In some cases, up to 30 years, which is why the investigations are complex."

Department of Health officials could not immediately say whether New Brunswick has had any other confirmed cases of CJD this year, or any deaths related to CJD.

What is CJD?

CJD is caused by abnormal folding of a protein in the brain called prion.

"It actually causes the brain cells to become toxic," said Nalini Sen, director of the research program at the Alzheimer Society of Canada.

"It can develop by just impacting one to a few brain cells and can then cause a spreading to take place across the entire brain."

Sen said there are different types of CJD, including classic CJD, which has three causes:

• Iatrogenic, when the disease is transmitted through a medical procedure.
• Familial, a gene mutation involved in 10 per cent of CJD cases.
• Sporadic, when the disease occurs spontaneously for no apparent reason. Sen said tissue contamination can also fall under this category.

Classic CJD is not related to variant CJD, also known as mad cow disease, suffered by people who have come into contact with infected cattle.

28 cases in New Brunswick

Symptoms of CJD can include visual disturbances, constant pain, poor co-ordination and mobility, memory loss and behavioural changes.

Sen said there is no cure or treatment to slow down the disease, but if people are experiencing symptoms, it's important they visit their family doctors for diagnosis.

"It's so severe that people typically don't live for longer than a year if they come into contact with the disease,"
 she said.  

According to the Public Health Agency of Canada, there have been 28 definite or probable cases of CJD in New Brunswick between January 1998 and 2019, and 971 cases in the country. 

Transmission 'nearly impossible'

Horizon said in its news release that it uses modern cleaning and sterilization processes that make transmission "nearly impossible."

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Dr. Kenneth Roberts, a Fredericton ophthalmologist and section leader for Eye Doctors of New Brunswick, said more than 8,000 cataract operations are performed in the province each year. 

"There have been no reported cases of a patient acquiring CJD from cataract surgery in the medical literature," he said. 

In a statement, he said the surgery is performed in hospital operating rooms following the same Canadian operating room protocols for cleaning and sterilization of instruments as for any other surgery.

Ensuring patient safety 

Roberts said the group is working with Horizon Health to ensure patient safety is maintained for all cataract surgeries performed across the province.

Horizon said the transmission of CJD by surgical instruments has only been documented on seven different occasions around the world.

These cases occurred between 20 and 40 years ago, and none were linked to cataract surgery.