Diagnostic challenges in rapidly progressive dementia

The diagnostic value of cognitive assessment indicators for mild cognitive impairment (MCI)

OBJECTIVE

This study aims to evaluate and analyze the standard diagnostic methods for mild cognitive impairment (MCI).

METHODS

This study used a prospective case-control study to examine baseline data and diagnostic indicators in a population of elderly with MCI. Based on different cognitive abilities, this study divided MCI and healthy control groups. The diagnostic indicators included CDT, MOCA, MMSE, PSQI, MBI, DST, HAMD, AD-related blood markers, and olfactory testing. The diagnostic value of each indicator was done using the ROC curve.

RESULTS

This study included 240 adult participants, 135 in the health group and 105 in the MCI group. A comparison of baseline data revealed statistically significant differences between the two groups regarding age, blood glucose, MMSE, CTD, MOCA, ability to perform daily living, AD-related blood indices and olfactory tests (all p < 0.05). Logistic regression analysis statistically showed that age, MOCA, and CDT were independent diagnostic factors for MCI (all p < 0.05). Combining these three indicators has the best diagnostic specificity (92.54%). AD-related blood and olfactory tests indices had only moderate diagnostic values (AUC: 0.7-0.8).

CONCLUSION

Age, MOCA, and CDT are good indicators for diagnosing early-stage MCI. AD-related blood indices and olfactory tests can serve as valuable adjuncts in diagnosing MCI.

MRI abnormalities in Creutzfeldt-Jakob disease and other rapidly progressive dementia

OBJECTIVE

To investigate brain MRI abnormalities in a cohort of patients with rapidly progressive dementia (RPD) with and without a diagnosis of Creutzfeldt-Jakob disease (CJD).

METHODS

One hundred and seven patients with diagnosis of prion disease (60 with definite sCJD, 33 with probable sCJD and 14 with genetic prion disease) and 40 non-prion related RPD patients (npRPD) underwent brain MRI including DWI and FLAIR. MRIs were evaluated with a semiquantitative rating score, which separately considered abnormal signal extent and intensity in 22 brain regions. Clinical findings at onset, disease duration, cerebrospinal-fluid 14-3-3 and t-tau protein levels, and EEG data were recorded.

RESULTS

Among patients with definite/probable diagnosis of CJD or genetic prion disease, 2/107 had normal DWI-MRI: in one patient a 2-months follow-up DWI-MRI showed CJD-related changes while the other had autopsy-proven CJD despite no DWI abnormalities 282 days after clinical onset. CJD-related cortical changes were detected in all lobes and involvement of thalamus was common. In the npRPD groups, 6/40 patients showed DWI alterations that clustered in three different patterns: (1) minimal/doubtful signal alterations (limbic encephalitis, dementia with Lewy bodies); (2) clearly suggestive of alternative diagnoses (status epilepticus, Wernicke or metabolic encephalopathy); (3) highly suggestive of CJD (mitochondrial disease), though cortical swelling let exclude CJD.

CONCLUSIONS

In the diagnostic work-up of RPD, negative/doubtful DWI makes CJD diagnosis rather unlikely, while specific DWI patterns help differentiating CJD from alternative diagnoses. The pulvinar sign is not exclusive of the variant form.

The Etiology of Rapidly Progressive Dementia: A 3-Year Retrospective Study in a Tertiary Hospital in China

Background

Rapidly progressive dementia (RPD), characterized by a rapid cognitive decline leading to dementia, comprises a diverse range of disorders. Despite advancements in diagnosis and treatment, research on RPD primarily focuses on Western populations.

Objective

This study aims to explore the etiology and demographics of RPD in Chinese patients.

Methods

We retrospectively analyzed 323 RPD inpatients at Huashan Hospital from May 2019 to March 2023. Data on sociodemographic factors, epidemiology, clinical presentation, and etiology were collected and analyzed.

Results

The median onset age of RPD patients was 60.7 years. Two-thirds received a diagnosis within 6 months of symptom onset. Memory impairment was the most common initial symptom, followed by behavioral changes. Neurodegenerative diseases accounted for 47.4% of cases, with central nervous system inflammatory diseases at 30.96%. Autoimmune encephalitis was the leading cause (16.7%), followed by Alzheimer's disease (16.1%), neurosyphilis (11.8%), and Creutzfeldt-Jakob disease (9.0%). Alzheimer's disease, Creutzfeldt-Jakob disease, and frontotemporal dementia were the primary neurodegenerative causes, while autoimmune encephalitis, neurosyphilis, and vascular cognitive impairment were the main non-neurodegenerative causes.

Conclusions

The etiology of RPD in Chinese patients is complex, with neurodegenerative and non-neurodegenerative diseases equally prevalent. Recognizing treatable conditions like autoimmune encephalitis and neurosyphilis requires careful consideration and differentiation.

Alzheimer's disease biomarker utilization at first referral enhances differential diagnostic precision with simultaneous exclusion of Creutzfeldt-Jakob disease

Most suspected Creutzfeldt-Jakob disease (CJD) cases are eventually diagnosed with other disorders. We assessed the utility of investigating Alzheimer's disease (AD) biomarkers and neurofilament light (NfL) in patients when CJD is suspected. The study cohort consisted of cerebrospinal fluid (CSF) samples referred for CJD biomarker screening wherein amyloid beta 1-42 (Aβ1-42), phosphorylated tau 181 (p-tau181), and total tau (t-tau) could be assessed via Elecsys immunoassays (n = 419) and NfL via enzyme-linked immunosorbent assay (ELISA; n = 161). In the non-CJD sub cohort (n = 371), 59% (219/371) had A+T- (abnormal Aβ1-42 only) and 21% (79/371) returned A+T+ (abnormal Aβ1-42 and p-tau181). In the 48 CJD subjects, a similar AD biomarker profile distribution was observed. To partially address the prevalence of likely pre-symptomatic AD, NfL was utilized to assess for neuronal damage. NfL was abnormal in 76% (25/33) of A+T- subjects 40 to 69 years of age, 80% (20/25) of whom had normal t-tau. This study reinforces AD as an important differential diagnosis of suspected CJD, highlighting that incorporating AD biomarkers and NfL at initial testing is worthwhile.

Retinal inner nuclear layer thickness in the diagnosis of cognitive impairment explored using a C57BL/6J mouse model

Major neurocognitive disorder (NCD) affects over 55 million people worldwide and is characterized by cognitive impairment (CI). This study aimed to develop a non-invasive diagnostic test for CI based upon retinal thickness measurements explored in a mouse model. Discrimination indices and retinal layer thickness of healthy C57BL/6J mice were quantified through a novel object recognition test (NORT) and ocular coherence tomography (OCT), respectively. Based on criteria from the Diagnostic and statistical manual of mental disorders 5th ed. (DSM-V), a diagnostic test was generated by transforming data into rolling monthly averages and categorizing mice into those with and without CI and those with a high or low decline in retinal layer thickness. Only inner nuclear layer thickness had a statistically significant relationship with discrimination indices. Furthermore, our diagnostic test was 85.71% sensitive and 100% specific for diagnosing CI, with a positive predictive value of 100%. These findings have potential clinical implications for the early diagnosis of CI in NCD. However, further investigation in comorbid mice and humans is warranted.

Prevalence and outcomes of rapidly progressive dementia: a retrospective cohort study in a neurologic unit in China

BACKGROUND

Rapidly progressive dementia (RPD) is a syndrome originating from various diseases. Recent advances have allowed a better understanding of its categories and spectrum; however, it remains challenging to make an accurate differential diagnosis and prognosis prediction.

METHODS

This study was a retrospective evaluation of all participants admitted to the neurology department of a single center in China from January 2015 to December 2019. The screened patients met the RPD criteria and their characteristics were collected to explore a diagnostic pattern of RPD. In addition, outcomes of RPD were evaluated with the Glasgow Outcome Scale (GOS), activities of daily living scale (ADL), and simplified Mini-Mental State Examination (MMSE), and different prognostic analysis methods were performed to determine the prognostic factors of RPD.

RESULTS

A total of 149 RPD patients among 15,731 inpatients were identified with an average MMSE value of 13.0 ± 4.6 at baseline. Etiological epidemiology revealed infectious, neurodegenerative and toxic/metabolic diseases as the three largest groups, accounting for 26.2%, 20.8% and 16.8% of all cases, respectively. In particular, prevalence rates of Creutzfeldt-Jakob disease (13.4%), Alzheimer's disease (11.4%), carbon monoxide poisoning (8.1%), neurosyphilis (5.4%) and dementia with Lewy bodies (5.4%) were highest in this series. A recommended diagnostic framework for RPD etiology was thus established. Follow-up evaluations showed a negative correlation between age and GOS scores (r=-0.421, P < 0.001), as well as age and simplified MMSE scores (r_s =- 0.393, P < 0.001), and a positive correlation between age and ADL scores (r_s =0.503, P < 0.001), and significantly different GOS, ADL and simplified MMSE scores across various etiologies (P = 0.003; F = 9.463, P < 0.001; F = 6.117, P < 0.001).

CONCLUSION

Infectious, neurodegenerative and toxic-metabolic entities were the most common RPD categories, and establishing a practical approach to RPD etiology would allow better disease management.

A case report of cerebral venous sinus thrombosis presenting with rapidly progressive dementia

Background

Cerebral venous sinus thrombosis (CVST) is a rare but serious and treatable cause of neurologic symptoms. Due to the variable clinical presentation, CVST was often misdiagnosed. According to published case reports, common clinical manifestations of CVST include headache, focal neurological deficit, epilepsy, papilledema, etc. It is rare, nevertheless, to mention cases of rapidly progressive dementia (RPD).

Case presentation

We reported a case of a 62-year-old retired male accountant, a Han Chinese from eastern China, who initially presented with slow response and memory decline. Until 2 months later, his memory declined and slow response deteriorated significantly, and he could not even complete simple tasks like brushing his teeth, washing his face, washing his feet, and dressing himself, and sometimes developed fecal incontinence. His neuropsychological test demonstrated severe cognitive decline. The cerebrospinal fluid (CSF) studies revealed markedly high opening pressure (260 mm of water), and coagulation tests indicated a mild elevation of D-Dimer of 1.19 mg/L. The magnetic resonance venography (MRV) showed thrombosis of the left transverse sinus, sigmoid sinus, and jugular venous bulb and was diagnosed as CVST. He switched from subcutaneous low molecular weight heparin (LMWH) and transitioned to oral anticoagulants at the time of discharge. The repeated CSF studies revealed normal opening pressure. After 5 days of anticoagulant treatment, his symptoms considerably improved, and a 1-month follow-up revealed that he had fully healed with no signs of recurrence.

Conclusion

This case demonstrated the clinical heterogeneity of CVST, which should be taken into account for differential diagnosis of RPD. This case study also offered fresh data for the categorization of the clinical traits and the diagnosis of CVST.

Rapidly progressive dementias - aetiologies, diagnosis and management

Rapidly progressive dementias (RPDs) are a group of heterogeneous disorders that include immune-mediated, infectious and metabolic encephalopathies, as well as prion diseases and atypically rapid presentations of more common neurodegenerative diseases. Some of these conditions are treatable, and some must be diagnosed promptly because of their potential infectivity. Prion disease is considered to be the prototypical RPD, but over the past two decades, epidemiological reports and the identification of various encephalitis-mediating antibodies have led to a growing recognition of other encephalopathies as potential causes of rapid cognitive decline. Knowledge of RPD aetiologies, syndromes and diagnostic work-up protocols will help clinicians to establish an early, accurate diagnosis, thereby reducing morbidity and mortality, especially in immune-mediated and other potentially reversible dementias. In this Review, we define the syndrome of RPD and shed light on its different aetiologies and on secondary factors that might contribute to rapid cognitive decline. We describe an extended diagnostic procedure in the context of important differential diagnoses, discuss the utility of biomarkers and summarize potential treatment options. In addition, we discuss treatment options such as high-dose steroid therapy in the context of therapy and diagnosis in clinically ambiguous cases.

The term ‘rapidly progressive dementia’ (RPD) describes a cognitive disorder with fast progression, leading to dementia within a relatively short time. This Review discusses the wide range of RPD aetiologies, as well as the diagnostic approach and treatment options.

Definitions of rapidly progressive dementia (RPD) vary according to the aetiological background and relate to the speed of cognitive decline, time from first symptom to dementia syndrome and/or overall survival.

RPD can occur in rapidly progressive neurodegenerative diseases, such as prion diseases, or in primarily slowly progressive diseases as a consequence of intrinsic factors or concomitant pathologies.

Besides neurodegenerative diseases, inflammatory (immune-mediated and infectious), vascular, metabolic and neoplastic CNS diseases are important and frequent causes of RPD.

To identify treatable causes of RPD, the technical diagnostic work-up must include MRI and analyses of blood and cerebrospinal fluid, and further diagnostics might be indicated in unclear cases.

Therapeutic options for many non-neurodegenerative causes of RPD are already available; disease-modifying therapies for neurodegenerative RPDs are an important focus of current research and could become a treatment option in the near future.

RT-QuIC and Related Assays for Detecting and Quantifying Prion-like Pathological Seeds of α-Synuclein

Various disease-associated forms or strains of α-synuclein (αSynD) can spread and accumulate in a prion-like fashion during synucleinopathies such as Parkinson’s disease (PD), Lewy body dementia (DLB), and multiple system atrophy (MSA). This capacity for self-propagation has enabled the development of seed amplification assays (SAAs) that can detect αSynD in clinical samples. Notably, α-synuclein real-time quaking-induced conversion (RT-QuIC) and protein misfolding cyclic amplification (PMCA) assays have evolved as ultrasensitive, specific, and relatively practical methods for detecting αSynD in a variety of biospecimens including brain tissue, CSF, skin, and olfactory mucosa from synucleinopathy patients. However, αSyn SAAs still lack concordance in detecting MSA and familial forms of PD/DLB, and the assay parameters show poor correlations with various clinical measures. End-point dilution analysis in αSyn RT-QuIC assays allows for the quantitation of relative amounts of αSynD seeding activity that may correlate moderately with clinical measures and levels of other biomarkers. Herein, we review recent advancements in α-synuclein SAAs for detecting αSynD and describe in detail the modified Spearman–Karber quantification algorithm used with end-point dilutions.

Gene expression and epigenetic markers of prion diseases

Epigenetics, meaning the variety of mechanisms underpinning gene regulation and chromatin states, plays a key role in normal development as well as in disease initiation and progression. Epigenetic mechanisms like alteration of DNA methylation, histone modifications, and non-coding RNAs, have been proposed as biomarkers for diagnosis, classification, or monitoring of responsiveness to treatment in many diseases. In prion diseases, the profound associations with human aging, the effects of cell type and differentiation on in vitro susceptibility, and recently identified human risk factors, all implicate causal epigenetic mechanisms. Here, we review the current state of the art of epigenetics in prion diseases and its interaction with genetic determinants. In particular, we will review recent advances made by several groups in the field profiling DNA methylation and microRNA expression in mammalian prion diseases and the potential for these discoveries to be exploited as biomarkers.

Rapidly progressive dementia in a nonagenarian with acute disseminated encephalomyelitis

We describe a case of rapidly progressive dementia (RPD) in a nonagenarian. Dementia was caused by an acute disseminated encephalomyelitis (ADEM). Although not frequently diagnosed in the very elderly acute disseminated encephalomyelitis should not be overlooked for it is a treatable condition. A recent infection followed by rapid cognitive deterioration and multifocal neurologic signs should raise the attention to curable autoimmune diseases. Although the cause of ADEM is still unclear, immune suppression is the mainstay of treatment. Most patients improve on high-dose glucocorticoids and eventually immune globulin treatment or plasma exchange if steroid-unresponsive.

Total and Phosphorylated Cerebrospinal Fluid Tau in the Differential Diagnosis of Sporadic Creutzfeldt-Jakob Disease and Rapidly Progressive Alzheimer’s Disease

Background: CSF total-tau (t-tau) became a standard cerebrospinal fluid biomarker in Alzheimer’s disease (AD). In parallel, extremely elevated levels were observed in Creutzfeldt-Jakob disease (CJD). Therefore, tau is also considered as an alternative CJD biomarker, potentially complicating the interpretation of results. We investigated CSF t-tau and the t-tau/phosphorylated tau181 ratio in the differential diagnosis of sCJD and rapidly-progressive AD (rpAD). In addition, high t-tau concentrations and associated tau-ratios were explored in an unselected laboratory cohort. Methods: Retrospective analyses included n = 310 patients with CJD (n = 205), non-rpAD (n = 65), and rpAD (n = 40). The diagnostic accuracies of biomarkers were calculated and compared. Differential diagnoses were evaluated in patients from a neurochemistry laboratory with CSF t-tau >1250 pg/mL (n = 199 out of 7036). Results: CSF t-tau showed an AUC of 0.942 in the discrimination of sCJD from AD and 0.918 in the discrimination from rpAD. The tau ratio showed significantly higher AUCs (p < 0.001) of 0.992 versus non-rpAD and 0.990 versus rpAD. In the neurochemistry cohort, prion diseases accounted for only 25% of very high CSF t-tau values. High tau-ratios were observed in CJD, but also in non-neurodegenerative diseases. Conclusions: CSF t-tau is a reliable biomarker for sCJD, but false positive results may occur, especially in rpAD and acute encephalopathies. The t-tau/p-tau ratio may improve the diagnostic accuracy in centers where specific biomarkers are not available.

Intravascular large B-cell lymphoma presenting as rapidly progressive dementia and stroke: A case report

RATIONALE

Intravascular large B-cell lymphoma (IVLBCL) is a rare form of large B-cell non-Hodgkin lymphoma. The diagnosis is challenging and frequently made at biopsy. Here we reported a case of IVLBCL limited to the central nervous system (CNS) presenting with progressive dementia and acute stroke, who was diagnosed by brain biopsy.

PATIENT CONCERNS

A 47-year-old woman was transferred to our hospital with a 6-month history of rapidly progressive dementia, and left limb weakness and numbness for 3 days. She was successively misdiagnosed with inflammatory demyelinating disease and stroke. Her condition deteriorated with elevated lactate dehydrogenase and multiple hyperintense lesions on the brain.

DIAGNOSIS

She was diagnosed with IVLBCL limited to the CNS by brain biopsy.

INTERVENTIONS

Bone marrow puncture and incisional random skin biopsy were not found neoplastic cells. Computed tomography scans were normal with no evidence of disease outside the CNS.

OUTCOMES

The patient died due to rapid clinical aggravation.

LESSONS

IVLBCL limited to the CNS is an aggressive disease with high mortality. Making a timely and correct diagnosis is crucial for early appropriate treatment in IVLBCL patients.

Development of α-Synuclein Real-Time Quaking-Induced Conversion as a Diagnostic Method for α-Synucleinopathies

Parkinson’s disease, dementia with Lewy bodies, and multiple system atrophy are characterized by aggregation of abnormal α-synuclein (α-syn) and collectively referred to as α-synucleinopathy. Because these diseases have different prognoses and treatments, it is desirable to diagnose them early and accurately. However, it is difficult to accurately diagnose these diseases by clinical symptoms because symptoms such as muscle rigidity, postural dysreflexia, and dementia sometimes overlap among these diseases. The process of conformational conversion and aggregation of α-syn has been thought similar to that of abnormal prion proteins that cause prion diseases. In recent years, in vitro conversion methods, such as real-time quaking-induced conversion (RT-QuIC), have been developed. This method has succeeded in amplifying and detecting trace amounts of abnormal prion proteins in tissues and central spinal fluid of patients by inducing conversion of recombinant prion proteins via shaking. Additionally, it has been used for antemortem diagnosis of prion diseases. Recently, aggregated α-syn has also been amplified and detected in patients by applying this method and many clinical studies have examined diagnosis using tissues or cerebral spinal fluid from patients. In this review, we discuss the utility and problems of α-syn RT-QuIC for antemortem diagnosis of α-synucleinopathies.

Understanding Creutzfeldt-Jackob disease from a viewpoint of amyloidogenic evolvability

Creutzfeldt-Jackob disease (CJD), the most common human prion disorder, is frequently accompanied by ageing-associated neurodegenerative conditions, such as Alzheimer’s disease and Parkinson’s disease. Although cross-seeding of amyloidogenic proteins (APs), including amyloid β and α-synuclein, may be critical in the co-morbidity of neurodegenerative disorders, the direct interaction of APs with prion protein (PrP), the central molecule involved in the pathogenesis of CJD, is unlikely. Currently, the nature of this biological interaction and its significance remain obscure. In this context, the objective of the present study is to discuss such interactions from the perspective of amyloidogenic evolvability, a putative function of APs. Hypothetically, both hereditary- and sporadic CJD might be attributed to the role of PrP in evolvability against multiple stressors, such as physical stresses relevant to concussions, which might be manifest through the antagonistic pleiotropy mechanism in ageing. Furthermore, accumulating evidence suggests that PrP- and other APs evolvability may negatively regulate each other. Provided that increased APs evolvability might be beneficial for acquired CJD in young adults, a dose-reduction of α-synuclein, a natural inhibitor of αS aggregation, might be therapeutically effective in upregulating APs evolvability. Collectively, a better understanding of amyloidogenic evolvability may lead to the development of novel therapies for CJD.

Diagnostic and prognostic value of plasma neurofilament light and total-tau in sporadic Creutzfeldt-Jakob disease

BACKGROUND

Blood neurofilament light (Nfl) and total-tau (t-tau) have been described to be increased in several neurological conditions, including prion diseases and other neurodegenerative dementias. Here, we aim to determine the accuracy of plasma Nfl and t-tau in the differential diagnosis of neurodegenerative dementias and their potential value as prognostic markers of disease severity.

METHODS

Plasma Nfl and t-tau were measured in healthy controls (HC, n = 70), non-neurodegenerative neurological disease with (NND-Dem, n = 17) and without dementia syndrome (NND, n = 26), Alzheimer's disease (AD, n = 44), Creutzfeldt-Jakob disease (CJD, n = 83), dementia with Lewy bodies/Parkinson's disease with dementia (DLB/PDD, n = 35), frontotemporal dementia (FTD, n = 12), and vascular dementia (VaD, n = 22). Biomarker diagnostic accuracies and cutoff points for the diagnosis of CJD were calculated, and associations between Nfl and t-tau concentrations with other fluid biomarkers, demographic, genetic, and clinical data in CJD cases were assessed. Additionally, the value of Nfl and t-tau predicting disease survival in CJD was evaluated.

RESULTS

Among diagnostic groups, highest plasma Nfl and t-tau concentrations were detected in CJD (fold changes of 38 and 18, respectively, compared to HC). Elevated t-tau was able to differentiate CJD from all other groups, whereas elevated Nfl concentrations were also detected in NND-Dem, AD, DLB/PDD, FTD, and VaD compared to HC. Both biomarkers discriminated CJD from non-CJD dementias with an AUC of 0.93. In CJD, plasma t-tau, but not Nfl, was associated with PRNP codon 129 genotype and CJD subtype. Positive correlations were observed between plasma Nfl and t-tau concentrations, as well as between plasma and CSF concentrations of both biomarkers (p < 0.001). Nfl was increased in rapidly progressive AD (rpAD) compared to slow progressive AD (spAD) and associated to Mini-Mental State Examination results. However, Nfl displayed higher accuracy than t-tau discriminating CJD from rpAD and spAD. Finally, plasma t-tau, but not plasma Nfl, was significantly associated with disease duration, offering a moderate survival prediction capacity.

CONCLUSIONS

Plasma Nfl and t-tau are useful complementary biomarkers for the differential diagnosis of CJD. Additionally, plasma t-tau emerges as a potential prognostic marker of disease duration.

Cerebrospinal Fluid and Blood Neurofilament Light Chain Protein in Prion Disease and Other Rapidly Progressive Dementias: Current State of the Art

Rapidly progressive dementia (RPD) is an umbrella term referring to several conditions causing a rapid neurological deterioration associated with cognitive decline and short disease duration. They comprise Creutzfeldt–Jakob disease (CJD), the archetypal RPD, rapidly progressive variants of the most common neurodegenerative dementias (NDs), and potentially treatable conditions such as infectious or autoimmune encephalitis and cerebrovascular disease. Given the significant clinical and, sometimes, neuroradiological overlap between these different disorders, biofluid markers also contribute significantly to the differential diagnosis. Among them, the neurofilament light chain protein (NfL) has attracted growing attention in recent years as a biofluid marker of neurodegeneration due to its sensitivity to axonal damage and the reliability of its measurement in both cerebrospinal fluid (CSF) and blood. Here, we summarize current knowledge regarding biological and clinical implications of NfL evaluation in biofluids across RPDs, emphasizing CJD, and other prion diseases. In the latter, NfL demonstrated a good diagnostic and prognostic accuracy and a potential value as a marker of proximity to clinical onset in pre-symptomatic PRNP mutation carriers. Similarly, in Alzheimer’s disease and other NDs, higher NfL concentrations seem to predict a faster disease progression. While increasing evidence indicates a potential clinical value of NfL in monitoring cerebrovascular disease, the association between NfL and prediction of outcome and/or disease activity in autoimmune encephalitis and infectious diseases has only been investigated in few cohorts and deserves confirmatory studies. In the era of precision medicine and evolving therapeutic options, CSF and blood NfL might aid the diagnostic and prognostic assessment of RPDs and the stratification and management of patients according to disease progression in clinical trials.

Cerebellar Vertigo as an Unspecific Initial Presentation of Creutzfeldt-Jakob Disease

BACKGROUND Creutzfeldt-Jakob disease (CJD) is a human prion disease characterized by severe and rapidly progressive fatal neurodegeneration. Currently, there is no cure for CJD, and death from CJD usually occurs within 1 year from the onset of the symptom, and the median survival time is 6 months. CASE REPORT The patient was a 63-year-old woman who presented to the hospital reporting having vertigo for the past 1 week and involuntary muscle contraction resulting in slow repetitive movement and abnormal posture for the past 3 days. A physical examination at the time of admission revealed unsteady gait, dystonia, and dysmetria of the left upper limb. There was no nystagmus on examination. Electroencephalography done on the same day showed focal epileptiform discharge on bilateral temporal lobes, which were more on the right side than the left. It also showed mild diffuse cerebral slowing. Cerebrospinal fluid analysis showed positive for RT-QulC, T tau protein, and 14-3-3. A diagnosis of CJD was made based on clinical course, imaging, and cerebrospinal fluid analysis. CONCLUSIONS The diagnosis of CJD can be suspected based on clinical signs and symptoms and can be confirmed after performing MRI, EEG, and lumbar puncture. Therefore, it is important to recognize vertigo as an unspecific symptom of CJD so that a timely diagnosis can be made and unnecessary procedures can be avoided.

Comparison between plasma and cerebrospinal fluid biomarkers for the early diagnosis and association with survival in prion disease

OBJECTIVE

To compare the diagnostic accuracy and the prognostic value of blood and cerebrospinal fluid (CSF) tests across prion disease subtypes.

METHODS

We used a single-molecule immunoassay to measure tau and neurofilament light chain (NfL) protein levels in the plasma and assessed CSF total(t)-tau, NfL and protein 14-3-3 levels in patients with prion disease (n=336), non-prion rapidly progressive dementias (n=106) and non-neurodegenerative controls (n=37). We then evaluated each plasma and CSF marker for diagnosis and their association with survival, taking into account the disease subtype, which is a strong independent prognostic factor in prion disease.

RESULTS

Plasma tau and NfL concentrations were higher in patients with prion disease than in non-neurodegenerative controls and non-prion rapidly progressive dementias. Plasma tau showed higher diagnostic value than plasma NfL, but a lower accuracy than the CSF proteins t-tau and 14-3-3. In the whole prion cohort, both plasma (tau and NfL) and CSF (t-tau, 14-3-3 and NfL) markers were significantly associated with survival and showed similar prognostic values. However, the intrasubtype analysis revealed that only CSF t-tau in sporadic Creutzfeldt-Jakob disease (sCJD) MM(V)1, plasma tau and CSF t-tau in sCJD VV2, and plasma NfL in slowly progressive prion diseases were significantly associated with survival after accounting for covariates.

CONCLUSIONS

Plasma markers have lower diagnostic accuracy than CSF biomarkers. Plasma tau and NfL and CSF t-tau are significantly associated with survival in prion disease in a subtype-specific manner and can be used to improve clinical trial stratification and clinical care.

Second-Generation RT-QuIC Assay for the Diagnosis of Creutzfeldt-Jakob Disease Patients in Brazil

The recent development of IQ-CSF, the second generation of real-time quaking-induced conversion (RT-QuIC) using cerebrospinal fluid (CSF), for the diagnosis of Creutzfeldt-Jakob Disease (CJD) represents a major diagnostic advance in the field. Highly accurate results have been reported with encouraging reproducibility among different centers. However, availability is still insufficient, and only a few research centers have access to the method in developing countries. In Brazil, we have had 603 suspected cases of CJD since 2005, when surveillance started. Of these, 404 were undiagnosed. This lack of diagnosis is due, among other factors, to the lack of a reference center for the diagnosis of these diseases in Brazil, resulting in some of these samples being sent abroad for analysis. The aim of this research study is to report the pilot use of IQ-CSF in a small cohort of Brazilian patients with possible or probable CJD, implementing a reference center in the country. We stored CSF samples from patients with possible, probable or genetic CJD (one case) during the time frame of December 2016 through June 2018. All CSF samples were processed according to standardized protocols without access to the clinical data. Eight patients presented to our team with rapidly progressive dementia and typical neurological signs of CJD. We used CSF samples from seven patients with other neurological conditions as negative controls. Five out of seven suspected cases had positive tests; two cases showed inconclusive results. Among controls, there was one false-positive (a CSF sample from a 5-year-old child with leukemia under treatment). The occurrence of a false positive in one of the negative control samples raises the possibility of the presence of interfering components in the CSF sample from patients with non-neurodegenerative pathologies. Our pilot results illustrate the feasibility of having CJD CSF samples tested in Brazilian centers and highlight the importance of interinstitutional collaboration to pursue a higher diagnostic accuracy in CJD in Brazil and Latin America.

Dressing Apraxia as Initial Manifestation of Creutzfeldt-Jakob Disease

Background

Creutzfeldt-Jakob disease (CJD) is a rare prion disease characterized by rapidly progressive dementia.

Case Report

A 76-year-old woman exhibited pronounced signs and symptoms of dressing apraxia for about seven weeks before the disease progressed and probable CJD was diagnosed supported by imaging and CSF findings.

Discussion

Dressing apraxia as the initial manifestation of CJD has been sparsely reported. This remarkably focal syndrome should be considered with view on movement and neuropsychological disorders in early CJD.

Diagnostic value of surrogate CSF biomarkers for Creutzfeldt-Jakob disease in the era of RT-QuIC

Prion real-time quaking-induced conversion (RT-QuIC) is emerging as the most potent assay for the in vivo diagnosis of Creutzfeldt-Jakob disease (CJD), but its full application, especially as a screening test, is limited by suboptimal substrate availability, reagent costs, and incomplete assay standardization. Therefore, the search for the most informative cerebrospinal fluid (CSF) surrogate biomarker is still of primary importance. We compared the diagnostic accuracy of CSF protein 14-3-3, measured with both western blot (WB) and enzyme-linked immunosorbent assay (ELISA), total (t)-tau and neurofilament light chain protein (NfL) alone or in combination with RT-QuIC in 212 subjects with rapidly progressive dementia in which we reached a highly probable clinical diagnosis at follow-up or a definite neuropathological diagnosis. T-tau performed best as surrogate CSF biomarker for the diagnosis of CJD (91.3% sensitivity and 78.9% specificity). The 14-3-3 ELISA assay demonstrated a slightly higher diagnostic value compared to the WB analysis (76.9% vs. 72.2%), but both methods performed worse than the t-tau assay. NfL was the most sensitive biomarker for all sCJD subtypes (> 95%), including those with low values of t-tau or 14-3-3, but showed the lowest specificity (43.1%). When ELISA-based biomarkers were adopted as screening tests followed by RT-QuIC, t-tau correctly excluded a higher number of non-CJD cases compared to NfL and 14-3-3 ELISA. Our study showed that among the CSF surrogate biomarkers of potential application for the clinical diagnosis of CJD, t-tau performs best either alone or as screening test followed by RT-QuIC as a second-level confirmatory test.