Enteral feeding is associated with longer survival in the advanced stages of prion disease

Evaluation of the Factors Influencing the Survival Times of Chinese Patients with Probable Creutzfeldt-Jacob Disease - China, 2020-2022

What is already known about this topic?

The clinical durations of sporadic Creutzfeldt-Jacob disease (sCJD) patients typically do not exceed 2 years, though considerable variation exists. The factors influencing survival among Chinese sCJD patients remain incompletely characterized.

What is added by this report?

A comprehensive evaluation of 31 factors across 7 categories was conducted in a retrospective cohort of 300 probable Chinese sCJD patients. The analysis revealed that patients over 65 years of age at onset, those presenting with pyramidal or extrapyramidal dysfunction, those showing high signal intensity in caudate/putamen on magnetic resonance imaging, and those not receiving nasal feeding demonstrated significantly shorter survival times.

What are the implications for public health practice?

This study provides the first systematic documentation of potential risk factors affecting survival times in Chinese sCJD patients, establishing an evidence base for developing and implementing targeted intervention strategies.

Prion diseases motor and neuropsychiatric symptom cluster pharmacotherapy: structured scoping review

BACKGROUND

Prion diseases are a group of rare, neurodegenerative conditions that are invariably fatal and cause a variety of symptoms, which can prove challenging to control. Through this paper, we aim to review the current evidence regarding pharmacological management of neuropsychiatric and motor symptoms of prion disease as well as draw on experts' and relatives' experience, to evaluate the current evidence and provide recommendations moving forwards.

METHODS

A scoping review of the literature for pharmacological management of symptoms was conducted using the systematic review tool, COVIDENCE, with searches conducted through four databases. 120 papers were selected for inclusion, and data extraction was carried out by two independent reviewers. Given the lack of high-quality data and small numbers, no further attempt at statistical analysis was made, and results are presented in a thematic synthesis.

RESULTS

Although a broad range of approaches and pharmacotherapies are trialled to manage these challenging symptoms, there are patterns emerging of some efficacy seen with the use of benzodiazepines, antipsychotic and anticonvulsant medications in both motor and neuropsychiatric symptoms in prion disease. These approaches and associated challenges were reflected in international expert opinion that was gathered via online survey.

CONCLUSION

There continues to be a paucity of good-quality evidence and we suggest a need for longitudinal, population-based and standardised research to allow a robust evidence base, which in turn will guide excellent symptom control and end of life care for this group of complex patients.

Creutzfeldt-Jakob disease and other prion diseases

Prion diseases share common clinical and pathological characteristics such as spongiform neuronal degeneration and deposition of an abnormal form of a host-derived protein, termed prion protein. The characteristic features of prion diseases are long incubation times, short clinical courses, extreme resistance of the transmissible agent to degradation and lack of nucleic acid involvement. Sporadic and genetic forms of prion diseases occur worldwide, of which genetic forms are associated with mutations in PRNP. Human to human transmission of these diseases has occurred due to iatrogenic exposure, and zoonotic forms of prion diseases are linked to bovine disease. Significant progress has been made in the diagnosis of these disorders. Clinical tools for diagnosis comprise brain imaging and cerebrospinal fluid tests. Aggregation assays for detection of the abnormally folded prion protein have a clear potential to diagnose the disease in peripherally accessible biofluids. After decades of therapeutic nihilism, new treatment strategies and clinical trials are on the horizon. Although prion diseases are relatively rare disorders, understanding their pathogenesis and mechanisms of prion protein misfolding has significantly enhanced the field in research of neurodegenerative diseases.

Human prion disease: molecular pathogenesis, and possible therapeutic targets and strategies

INTRODUCTION

Human prion diseases are heterogeneous, and often rapidly progressive, transmissible neurodegenerative disorders associated with misfolded prion protein (PrP) aggregation and self-propagation. Despite their rarity, prion diseases comprise a broad spectrum of phenotypic variants determined at the molecular level by different conformers of misfolded PrP and host genotype variability. Moreover, they uniquely occur in idiopathic, genetically determined, and acquired forms with distinct etiologies.

AREA COVERED

This review provides an up-to-date overview of potential therapeutic targets in prion diseases and the main results obtained in cell and animal models and human trials. The open issues and challenges associated with developing effective therapies and informative clinical trials are also discussed.

EXPERT OPINION

Currently tested therapeutic strategies target the cellular PrP to prevent the formation of misfolded PrP or to favor its elimination. Among them, passive immunization and gene therapy with antisense oligonucleotides against prion protein mRNA are the most promising. However, the disease's rarity, heterogeneity, and rapid progression profoundly frustrate the successful undertaking of well-powered therapeutic trials and patient identification in the asymptomatic or early stage before the development of significant brain damage. Thus, the most promising therapeutic goal to date is preventing or delaying phenoconversion in carriers of pathogenic mutations by lowering prion protein expression.

Development of novel clinical examination scales for the measurement of disease severity in Creutzfeldt-Jakob disease

OBJECTIVE

To use a robust statistical methodology to develop and validate clinical rating scales quantifying longitudinal motor and cognitive dysfunction in sporadic Creutzfeldt-Jakob disease (sCJD) at the bedside.

METHODS

Rasch analysis was used to iteratively construct interval scales measuring composite cognitive and motor dysfunction from pooled bedside neurocognitive examinations collected as part of the prospective National Prion Monitoring Cohort study, October 2008-December 2016.A longitudinal clinical examination dataset constructed from 528 patients with sCJD, comprising 1030 Motor Scale and 757 Cognitive Scale scores over 130 patient-years of study, was used to demonstrate scale utility.

RESULTS

The Rasch-derived Motor Scale consists of 8 items, including assessments reliant on pyramidal, extrapyramidal and cerebellar systems. The Cognitive Scale comprises 6 items, and includes measures of executive function, language, visual perception and memory. Both scales are unidimensional, perform independently of age or gender and have excellent inter-rater reliability. They can be completed in minutes at the bedside, as part of a normal neurocognitive examination. A composite Examination Scale can be derived by averaging both scores. Several scale uses, in measuring longitudinal change, prognosis and phenotypic heterogeneity are illustrated.

CONCLUSIONS

These two novel sCJD Motor and Cognitive Scales and the composite Examination Scale should prove useful to objectively measure phenotypic and clinical change in future clinical trials and for patient stratification. This statistical approach can help to overcome obstacles to assessing clinical change in rapidly progressive, multisystem conditions with limited longitudinal follow-up.

The importance of ongoing international surveillance for Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD) is a rapidly progressive, fatal and transmissible neurodegenerative disease associated with the accumulation of misfolded prion protein in the CNS. International CJD surveillance programmes have been active since the emergence, in the mid-1990s, of variant CJD (vCJD), a disease linked to bovine spongiform encephalopathy. Control measures have now successfully contained bovine spongiform encephalopathy and the incidence of vCJD has declined, leading to questions about the requirement for ongoing surveillance. However, several lines of evidence have raised concerns that further cases of vCJD could emerge as a result of prolonged incubation and/or secondary transmission. Emerging evidence from peripheral tissue distribution studies employing high-sensitivity assays suggests that all forms of human prion disease carry a theoretical risk of iatrogenic transmission. Finally, emerging diseases, such as chronic wasting disease and camel prion disease, pose further risks to public health. In this Review, we provide an up-to-date overview of the transmission of prion diseases in human populations and argue that CJD surveillance remains vital both from a public health perspective and to support essential research into disease pathophysiology, enhanced diagnostic tests and much-needed treatments.