Barriers to Autopsy: Creutzfeldt-Jakob Disease in New York State

Prion diseases reported in the "Annual of the Pathological Autopsy Cases in Japan"

BACKGROUND

For surveillance projects to be successful, it is important to accurately diagnose all patients, without overlooking any cases. Here, we investigated the present clinical diagnostic accuracy for prion diseases in Japan.

METHODS

We analyzed volumes of the "Annual of the Pathological Autopsy Cases in Japan", which reported details on 130,105 autopsies conducted from 2007 to 2016 throughout Japan.

RESULTS

The clinical diagnosis of patients with prion disease had a specificity of 91.3% and a sensitivity of 96.3%. The autopsy rates were estimated as 17.8% for patients with clinically suspected prion disease and as 1.8% for the entire population.

CONCLUSIONS

Despite the good accuracy of clinical diagnoses of prion diseases, a calculated 78.4 patients with prion disease were expected to have gone undiagnosed during the 10-year study period. However, autopsy is estimated to reveal a maximum of only 13.8 of these clinically undiagnosed patients because of the low autopsy rate. The overall autopsy rate, irrespective of any specific disorder, must increase for effective surveillance projects of disease incidence to be conducted.

Human prion diseases and the risk of their transmission during anatomical dissection

Prion diseases (or transmissible spongiform encephalopathies) are a unique group of fatal progressive neurodegenerative diseases of the central nervous system. The infectious agent is hypothesized to consist solely of a highly protease-resistant misfolded isoform of the host prion protein. Prions display a remarkable degree of resistance to chemical and physical decontamination. Many common forms of decontamination or neutralization used in infection control are ineffective against prions, except chaotropic agents that specifically disrupt proteins. Human cadaveric prosection or dissection for the purposes of teaching and demonstration of human anatomy has a distinguished history and remains one of the fundamentals of medical education. Iatrogenic transmission of human prion diseases has been demonstrated from the inoculation or implantation of human tissues. Therefore, although the incidence of human prion diseases is rare, restrictions exist upon the use of tissues from patients reported with dementia, specifically the brain and other central nervous system material. A current concern is the potential for asymptomatic variant Creutzfeldt-Jakob disease transmission within the UK population. Therefore, despite the preventative measures, the transmission of prion disease through human tissues remains a potential risk to those working with these materials. In this review, we aim to summarize the current knowledge on human prion disease relevant to those working with human tissues in the context of anatomical dissection.

Prion disease risk perception in Canadian medical laboratories

BACKGROUND

There are no national guidelines specific for handling prion-associated specimens in Canadian medical laboratories. Medical laboratory workers may perceive themselves at risk of prion transmission and, on occasion, decline to process such specimens.

OBJECTIVE

To examine the knowledge, attitudes and reported behaviours of medical laboratory workers in relation to prion disease to understand their risk perception and the need for national laboratory guidelines on prion infection control.

DESIGN

Survey development and cross-sectional web-based administration.

METHODS

The survey was developed through key informant interviews and a modified Delphi process. Medical laboratory workers across Canada were invited by laboratory managers and national organizations to complete the web-based survey.

RESULTS

Twelve key informant interviews were performed. Consensus for questionnaire content was reached through two rounds of the Delphi process. Responses were received from 426 Canadian medical laboratory workers; 37% of medical laboratory staff reported processing prion-associated specimens. Different protocols for specimen processing were followed, and 18% believed they were at risk when processing these specimens. Less than one-third of those receiving specimens believed they were adequately trained. The mean (±SD) knowledge score was 9.25±4.5/24; individuals who had received training scored significantly higher than those who were untrained (P<0.01). Eighty-one per cent of respondents would be more comfortable processing specimens if national guidelines existed and were used in their laboratory.

CONCLUSION

There is a high perception of risk and few perceived benefits of processing prion-associated specimens. National guidelines for prion infection control in medical laboratories and adequate training would enable medical laboratory workers to process these specimens efficiently and confidently.

Using qualitative methods to investigate risk perception of Canadian medical laboratory workers in relation to current prion disease infection control policies

The aim of this study was to determine the rationale, methodology, and progress of risk perceptions of laboratory workers in relation to existing prion disease infection control policies in Canadian medical laboratories. This study developed a Web survey that investigated the knowledge, behavior, and attitudes of laboratory staff in order to (1) identify strengths, weaknesses, and gaps of current prion infection prevention and control guidelines and (2) inform the development of national medical lab specific guidelines. The use of qualitative methods to develop a relevant survey is described and future research activities are outlined. Preliminary, qualitative data indicate that, among laboratory staff, there is a high degree of perceived susceptibility toward prion transmission in medical laboratories. Significant barriers to following existing prion infection control guidelines are reported with few benefits of following these guidelines. As a result, laboratories take precautions above those that are required when processing suspect prion-infected specimens, which may result in testing delays. A focused survey for laboratory staff that addresses these issues will provide insight on the necessary steps that will ensure safe and efficient diagnostic testing for suspect prion specimens.

The conventional autopsy in modern medicine

In many countries, including the UK, where relatives' consent is required, clinical autopsy rates (i.e. autopsies other than those required by law) have been declining since the 1950s. In the UK, even in teaching hospitals, the clinical autopsy rate has fallen to only 10% of deaths or less. At this rate of decline, clinical autopsies - and the pathologists who perform them - face extinction. The future practice of medicine will be blind to the many adverse consequences of clinical actions or omissions. The reasons for this decline are manifold and these have to be addressed if autopsy is to stand a chance of survival. The future of autopsy lies in promoting public support for autopsies, in some cases adapting the autopsy to address specific questions, thus making more effective use of information from autopsies. Only by ensuring that the next generation of doctors have experienced the powerful educational benefit of examining the body after death will the importance of autopsy to modern medicine be understood.

Prion proteins: a biological role beyond prion diseases

The biological role of the scrapie isoform of prion protein (PrP(Sc)) as an infectious agent in numerous human and non-human disorders of the central nervous system is well established. In contrast, and despite decades of intensive research, the physiological function of the endogenous cellular form of the prion protein (PrP(C)) remains elusive. In mammals, the ubiquitous expression of PrP(C) suggests biological functions other than its pathological role in propagating the accumulation of its misfolded isotype. Other functions that have been attributed to PrP(C) include signal transduction, synaptic transmission and protection against cell death through the apoptotic pathway. More recently, immunoregulatory properties of PrP(C) have been reported. We review accumulating in vitro and in vivo evidence regarding physiological functions of PrP(C).