Nation's experts work to identify mystery disease

By Sandi Doughton
Seattle Times staff reporter

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The disease is clearly not the human form of mad-cow, nor does it appear to be Creutzfeldt-Jakob Disease (CJD), a closely related condition, said Dr. Pierluigi Gambetti, director of the National Prion Disease Pathology Surveillance Center.

"We really are puzzled at this time," he said yesterday. "This is unusual."

The condition of the patient was not available.

Blood tests conducted over the next two to three weeks should provide more information on the mysterious ailment, said Gambetti, whose Cleveland lab analyzes most of the so-called prion diseases diagnosed in the United States.

Prions are the misshapen proteins believed to cause a family of deadly, brain-wasting diseases that include human forms such as CJD and animal versions such as mad-cow and scrapie. Scientists think the human form of mad-cow disease, also called variant CJD, is probably caused by eating infected beef. But the causes of other prion diseases are not well-understood, though genetic factors play a role in some cases.

Because they are proteins, not microbes, prions are resistant to most ordinary sterilization techniques. Surgical instruments used to take a biopsy from the Seattle patient's brain were used subsequently in up to 12 other brain surgeries before being subjected to the supercleaning prescribed for prion diseases, hospital officials said.

Human prion disease There are five known human prion diseases: Sporadic Creutzfeldt-Jakob disease is believed to arise spontaneously in one person in a million and is more common in the elderly. Some cases also have been caused by contaminated surgical instruments or contaminated brain implants, corneal transplants and blood transfusion. Variant Creutzfeldt-Jakob disease is believed to be caused by eating beef infected with mad-cow disease and mainly strikes young people. Kuru was discovered in New Guinea, where it was spread by the practice of cannibalizing human brains. Fatal Familial Insomnia, marked by progressive sleeplessness, is genetically linked and has been found only in nine extended families. Gerstmann-Straüssler- Scheinker also is caused by genetic mutations and occurs in only about 50 extended families. Sources: CDC; Medscape

But Gambetti said the risk to those patients is slight.

"The chances that this disease is transmissible are very, very low," he said.

The hospital is reviewing its records and will decide whether the patients should be notified once the disease is positively identified, said Johnese Spisso, Harborview's chief operating officer.

"We need to sit down and review all the facts so we know what to tell people," she said. "We need to make sure we give them the best information possible so we don't unduly alarm people."

There are only six cases on record of a prion disease — specifically CJD — being transmitted through contaminated surgical instruments or brain electrodes, said Dr. Ermias Belay of the U.S. Centers for Disease Control and Prevention. And all of those cases occurred before 1976, when common sterilization techniques were improved, said Belay, who helped write international guidelines for prion sterilization.

It's possible the strain from Harborview is a type that can't be passed from one person to another, even through a direct dose to the brain, Gambetti said.

Preliminary tests show that it most closely resembles an extremely rare prion disease named GSS for the three German scientists who discovered it (Gerstmann-Straüssler-Scheinker). GSS can be triggered by a dozen different genetic mutations, Gambetti said, and only one of those forms has been shown to be transmissible in laboratory animals.

But even if the risk is minuscule, the diseases are so horrible that hospitals always should err on the side of caution when it comes to sterilizing instruments, said Florence Kranitz, president of the CJD Foundation, a support and advocacy group.

Invariably fatal, CJD and its close cousins progressively destroy the brains of their victims, robbing them of their memories and their ability to move or speak.

"I sure don't want them doing surgery on anyone I know and love with instruments that have been contaminated by prions," Kranitz said.

The CDC recommends that hospitals superclean instruments used for brain surgery on all patients where prion diseases haven't been ruled out, Belay said. Another option is to "quarantine" the instruments, not using them again until a final diagnosis eliminates the possibility of prion disease.

But Harborview officials say two preliminary tests on the patient were negative for CJD, which, though it strikes only about 300 Americans a year, is the most common human prion disease.

"In the opinion of the neurologist, this was not CJD," said Dr. Tom Montine, the hospital's director of neuropathology.

So the hospital used its normal sterilization techniques: Soaking the instruments in an enzyme solution, followed by a high-pressure wash and a 272-degree vacuum autoclave.

Two weeks later, when the patient's biopsy results hinted at the possibility of a prion disease, the hospital supersterilized the instruments according to CDC's guidelines, which include an hourlong soak in sodium hydroxide — the powerful caustic also called lye — before the high-temperature autoclave.

"We feel confident we followed the recommended national sterilization standards based on the patient's clinical information," said Harborview spokeswoman Susan Gregg-Hanson.

She said the hospital is reviewing the case and may change its procedures if the review finds flaws.

Similar cases over the past few years have raised concern about sterilization techniques in the U.S., Canada and the United Kingdom.

Doctors at a Denver hospital operated on six people in 2001 with the same instruments used to take a brain biopsy from a woman who later died of CJD. Two of the patients are suing the hospital.

Several patients settled lawsuits filed against Tulane University Hospital in New Orleans after a similar occurrence in 2000 may have exposed eight people to CJD.

In 2001, Madigan Army Medical Center in Pierce County closed its operating rooms two days for extra sterilization after discovering a woman who had undergone surgery there four months before had CJD. The hospital notified five people who might have been exposed.

Britain, where a mad-cow epidemic wiped out herds and infected more than 100 people, is spending more than $350 million to upgrade sterilization equipment.

Sandi Doughton: 206-464-2491 or sdoughton@seattletimes.com

Copyright © 2004 The Seattle Times Company

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