CSF analysis in patients with sporadic CJD and other transmissible spongiform encephalopathies

Oligoclonal bands

Oligoclonal bands (OCBs) represent the presence of intrathecal immunoglobulin G (IgG) as detected by isoelectric focusing and immunofixation. Cerebrospinal fluid (CSF) analysed alongside a paired serum sample gives five different immunofixation patterns. These are: type 1-the normal physiological state with no intrathecal IgG synthesis; type 2-evidence for intrathecal IgG synthesis, with CSF-restricted OCBs; type 3-evidence for intrathecal IgG synthesis, with CSF-restricted OCBs, but with additional, identical bands in the CSF and serum; type 4-absence of intrathecal IgG synthesis, but with identical OCBs in CSF and serum; and type 5-absence of intrathecal IgG synthesis, with a monoclonal band in CSF and serum. Analysis of these patterns can help to diagnose a range of neurological conditions, including multiple sclerosis. However, it is important to interpret OCB results alongside other CSF tests and their clinical context.

[Clinical characteristics and diagnostics of human spongiform encephalopathies: an update]

Human spongiform encephalopathies are rare transmissible neurodegenerative diseases of the brain and the nervous system that are caused by misfolding of the physiological prion protein into a pathological form and its deposition in the central nervous system (CNS). Prion diseases include Creutzfeldt-Jakob disease (CJD, sporadic or familial), Gerstmann-Straussler-Scheinker syndrome (GSS) and fatal familial insomnia (FFI). Prion diseases can be differentiated into three etiological categories: spontaneous (sporadic CJD), inherited (familial CJD, FFI, and GSS) and acquired (variant CJD and iatrogenic CJD). Most cases occur sporadically. Prion diseases can lead to a variety of neurological symptoms and always have an inevitably fatal course. Cerebrospinal fluid analysis and magnetic resonance imaging (MRI) play a crucial role in the diagnostics of prion diseases and may facilitate an early and reliable clinical diagnosis. A causal treatment or specific therapeutic agents are not yet available. In general, a palliative therapeutic concept is indicated.

Hereditary Creutzfeldt-Jakob Disease: A Case Presentation of a Rare Stroke Mimic

Acute ischemic cerebrovascular accident (CVA) is a time-sensitive emergent diagnosis, requiring rapid diagnosis and consideration of thrombolytic administration. However, a myriad of cerebrovascular mimics creates a diagnostic challenge. A rare CVA mimic is Creutzfeldt-Jakob disease (CJD), a rapidly progressive fatal dementia due to protein misfolding. Magnetic resonance imaging (MRI) and neurology consultation for electroencephalogram (EEG) and specialized cerebrospinal fluid (CSF) studies are diagnostic while the patient is alive. All forms are fatal within months, and diagnosis can be confirmed on postmortem brain testing. While incredibly uncommon, emergency clinicians should consider this diagnosis in the proper patient to advocate for specialized CSF testing and potential palliative care consultation.

A case report of fatal familial insomnia with cerebrospinal fluid leukocytosis during the COVID-19 epidemic and review of the literature

Fatal familial insomnia (FFI) is a rare autosomal dominant genetic neurodegenerative disease. Generally, FFI patients will develop rapidly progressive dementia, sleep disturbance, autonomic dysfunction, and so on. Cerebrospinal fluid examination of FFI patients normally shows no obvious abnormalities. Here, we report a young male patient who was diagnosed with FFI during the COVID-19 epidemic. Clinical symptoms include psychobehavioral abnormality, cognitive decline, sleep disturbance, and autonomic dysfunction. No abnormalities were found in routine examinations after admission. However, the number of white blood cells in the cerebrospinal fluid increased. Though the patient was treated with anti-infection and immunotherapy, the symptoms were not relieved. A lumbar puncture was performed again, and it was found that the total Tau protein in the cerebrospinal fluid was elevated, and PET results showed that brain metabolism decreased. Finally, a genetic test was used to confirm the diagnosis of FFI. This case suggests that patients with FFI may also have elevated white blood cells in cerebrospinal fluid and timely detection of Tau protein in cerebrospinal fluid is helpful for early identification of FFI. And precise diagnosis relies on genetic testing.

Diagnostic approach in a patient with Creutzfeldt-Jakob disease

Prion diseases are an important cause of rapidly progressive dementias. Among them, the most common is sporadic Creutzfeldt-Jakob disease (CJD). It is a rare and incurable disease, with rapid progression to death.

Objective

To describe the diagnostic approach of a patient with Creutzfeldt-Jakob disease.

Methods

The diagnosis is established through the clinical picture associated with characteristic changes in the brain magnetic resonance imaging, the electroencephalogram, and analysis of specific changes in the cerebrospinal fluid.

Results

The present report describes the case of a 53-year-old patient in the city of Fortaleza-CE. The diagnosis was made based on the clinical condition and through diagnostic tests, including 14-3-3 protein and RT QUIC analysis. Differential diagnosis was performed with other rapidly progressive causes, such as infectious and immune-mediated diseases.

Conclusions

The diagnosis of probable sporadic CJD was established.

The First Sporadic Creutzfeldt-Jakob Disease Case with a Rare Molecular Subtype VV1 and 1-Octapeptide Repeat Deletion in PRNP

In the present manuscript, we report the clinical presentation and challenging diagnostic work-up of a sporadic Creutzfeldt–Jakob disease patient with confirmed VV1 subtype and heterozygous 1-octapeptide repeat deletion in the prion protein gene. The described patient was a 58-year-old woman. Interestingly, most of the reported patients with the VV1 subtype to date are men with an average age of 44 years at disease onset. The patient was observed clinically from symptoms onset until her death 22 months later. This report describes the patient’s insidious clinical evolution and the paraclinical examinations and pathology reports gathered at different time points of disease progression. Unfortunately, the absence of typical clinical and paraclinical features of classic sporadic Creutzfeldt–Jakob disease made the brain biopsy surgery necessary. This case report illustrates the diagnostic difficulties posed by the phenotypic heterogeneity of sporadic Creutzfeldt–Jakob disease and urges clinicians to consider this diagnosis even in patients who do not fulfil the typical clinical disease criteria. Furthermore, it highlights the need for real-time quaking-induced conversion method adaptation for detection of rare sporadic Creutzfeldt–Jakob disease subtypes with certain prion protein gene variants.

A rare case of Creutzfeldt-Jakob disease reported from Nepal

Creutzfeldt-Jakob disease, though rare, should be considered in the clinical picture of rapidly progressive dementia and absence of verbal response as evident in our case despite the absence of typical radiological picture.

Detection of Prions in Brain Homogenates and CSF Samples Using a Second-Generation RT-QuIC Assay: A Useful Tool for Retrospective Analysis of Archived Samples

The possibilities for diagnosing prion diseases have shifted significantly over the last 10 years. The RT-QuIC assay option has been added for neuropsychiatric symptoms, supporting biomarkers and final post-mortem confirmation. Samples of brain homogenates used for final diagnosis, archived for many years, provide the possibility for retrospective studies. We used a second-generation RT-QuIC assay to detect seeding activity in different types of sporadic and genetic prion diseases in archival brain homogenates and post-mortem CSF samples that were 2 to 15 years old. Together, we tested 92 archival brain homogenates: 39 with definite prion disease, 28 with definite other neurological disease, and 25 with no signs of neurological disorders. The sensitivity and specificity of the assay were 97.4% and 100%, respectively. Differences were observed in gCJD E200K, compared to the sporadic CJD group. In 52 post-mortem CSF samples-24 with definite prion disease and 28 controls-we detected the inhibition of seeding reaction due to high protein content. Diluting the samples eliminated such inhibition and led to 95.8% sensitivity and 100% specificity of the assay. In conclusion, we proved the reliability of archived brain homogenates and post-mortem CSF samples for retrospective analysis by RT-QuIC after long-term storage, without changed reactivity.

Could Sporadic Creutzfeldt-Jakob Disease Be Underdiagnosed in China? Experience From Four Cases

Background: Creutzfeldt-Jakob Disease (CJD) is a rapidly progressive neurodegenerative disease caused by the misfolded version of the cellular prion protein. Here we report four cases of sporadic CJD (sCJD) and describe the diagnostic methods available in order avoid missed or delayed recognition of CJD in China.

Case presentation: We report four patients diagnosed with sCJD between March 2018 and December 2019 at Xiangya Hospital and the Second Xiangya Hospital of Central South University. All patients were admitted to the hospital because of a progressive cognitive decline. Although their routine tests and biochemical indicators in the cerebrospinal fluid (CSF), as well as computed tomography (CT) imaging, did not reveal any apparent abnormalities, the presence of “cortical ribboning” was incidentally found on diffusion-weighted imaging (DWI). The patients were subsequently diagnosed with CJD based on positive testing for 14-3-3 protein in their CSF, and the presence of periodic sharp and slow wave complexes (PSWCs) on their electroencephalograms (EEG). Additionally, two of patients was confirmed pathological examination of cerebral biopsies demonstrating neuronal loss, gliosis, and spongiform changes.

Conclusions: CJD is a rare disease and is easily misdiagnosed by clinician in China due to a lack of recognition and awareness of CJD. Based on our experience described in this report, enhanced vigilance for CJD is required for patients with rapidly progressive dementia in China and other developing countries. DWI, EEG and detection of 14-3-3 protein in CSF should be performed in order to achieve a timely diagnosis of CJD.

The first reported case of Creutzfeldt-Jakob disease from Nepal

Creutzfeldt-Jakob disease (CJD) can also be diagnosed in a resource-limited setting through good clinical analysis. The diagnosis of CJD should be considered in patients with rapidly evolving neurological signs associated with cognitive disturbances even in countries with limited available sophisticated tools and where CJD was never reported before.

RT-QuIC: a new test for sporadic CJD

The diagnosis of sporadic Creutzfeldt-Jakob disease (CJD) can be difficult, but the real-time quaking-induced conversion (RT-QuIC) assays have made a considerable impact on its clinical diagnosis. This technique exploits the ability of the misfolded pathological form of prion protein (PrP^Sc) found in cerebrospinal fluid (CSF) to induce conversion of normal PrP to the misfolded form, which subsequently aggregates. The formation of these aggregates of misfolded PrP is monitored in real time using fluorescent dyes. The current sensitivity of CSF RT-QuIC undertaken at the UK National CJD Research & Surveillance Unit is 92% and the specificity is 100%. The interpretation of the RT-QuIC traces is affected by the presence of raised CSF red and white cells counts and elevated total protein concentrations. We recommend that CSF samples for RT-QuIC analysis are clear and colourless with a white cell count of <10 x10^6/L and have a total protein concentration of <1 g/L.

Sporadic Creutzfeldt-Jakob disease

Sporadic Creutzfeldt-Jakob disease (CJD), the most common human prion disease, is generally regarded as a spontaneous neurodegenerative illness, arising either from a spontaneous PRNP somatic mutation or a stochastic PrP structural change. Alternatively, the possibility of an infection from animals or other source remains to be completely ruled out. Sporadic CJD is clinically characterized by rapidly progressive dementia with ataxia, myoclonus, or other neurologic signs and, neuropathologically, by the presence of aggregates of abnormal prion protein, spongiform change, neuronal loss, and gliosis. Despite these common features the disease shows a wide phenotypic variability which was recognized since its early descriptions. In the late 1990s the identification of key molecular determinants of phenotypic expression and the availability of a large series of neuropathologically verified cases led to the characterization of definite clinicopathologic and molecular disease subtypes and to an internationally recognized disease classification. By showing that these disease subtypes correspond to specific agent strain-host genotype combinations, recent transmission studies have confirmed the biologic basis of this classification. The introduction of brain magnetic resonance imaging techniques such as fluid-attenuated inversion recovery and diffusion-weighted imaging sequences and cerebrospinal fluid biomarker assays for the detection of brain-derived proteins as well as real-time quaking-induced conversion assay, allowing the specific detection of prions in accessible biologic fluids and tissues, has significantly contributed to the improved accuracy of the clinical diagnosis of sporadic CJD in recent years.

Differential diagnosis with other rapid progressive dementias in human prion diseases

Prion diseases are unique in medicine as in humans they occur in sporadic, genetic, and acquired forms. The most common human prion disease is sporadic Creutzfeldt-Jakob disease (CJD), which commonly presents as a rapidly progressive dementia (RPD) with behavioral, cerebellar, extrapyramidal, and some pyramidal features, with the median survival from symptom onset to death of just a few months. Because human prion diseases, as well as other RPDs, are relatively rare, they can be difficult to diagnose, as most clinicians have seen few, if any, cases. Not only can prion diseases mimic many other conditions that present as RPD, but some of those conditions can present similarly to prion disease. In this article, the authors discuss the different etiologic categories of conditions that often present as RPD and also present RPDs that had been misdiagnosed clinically as CJD. Etiologic categories of conditions are presented in order of the mnemonic used for remembering the various categories of RPDs: VITAMINS-D, for vascular, infectious, toxic-metabolic, autoimmune, mitochondrial/metastases, iatrogenic, neurodegenerative, system/seizures/sarcoid, and demyelinating. When relevant, clinical, imaging, or other features of an RPD that overlap with those of CJD are presented.

Creutzfeldt-Jakob disease: recent developments

Creutzfeldt-Jakob disease (CJD) is a rare prion disorder that has been the subject of both professional and public interest following the identification of variant CJD as a zoonotic disorder. There have been recent advances in diagnostic techniques, including real-time quaking-induced conversion and magnetic resonance imaging brain scan, that have allowed more accurate case recognition in all forms of CJD. Although the epidemic of variant CJD is clearly in decline, prevalence studies suggest that it may be premature to be complacent about concerns for public health.

Infectious and Sporadic Prion Diseases

Prion diseases are progressive fatal encephalopathies characterized by a neurodegenerative pathology, the tissue deposition of abnormally folded prion protein and, in general, potential transmissibility. Creutzfeldt-Jakob disease (CJD) is the commonest human prion disease and occurs in three principal forms: sporadic (idiopathic), acquired (infectious), and inherited (genetic). This chapter concerns the sporadic and acquired forms. Sporadic CJD occurs worldwide and affects mainly the middle aged and elderly. There are recognized genetic risk factors-most importantly the PRNP-129 polymorphism. The acquired forms of CJD consist of iatrogenic CJD (accidental transmission of CJD via medical or surgical procedures) and variant CJD (vJCD) (which originated as a zoonosis via bovine spongiform encephalopathy (BSE)-contamination of human food). The main causes of iatrogenic CJD are cadaveric-derived human growth hormone treatment and dura mater surgical grafts. The PRNP-129 polymorphism has important effects on iatrogenic infection, including overall susceptibility and incubation period. vCJD, resulting from dietary exposure to BSE, has affected mostly the United Kingdom, followed by France. All tested cases were originally PRNP-129MM, although two MV cases have been identified recently (one possible; one definite). vCJD has been secondarily transmitted via blood transfusion and a blood product. There is continuing concern over secondary transmission since there is evidence-from lymphoreticular tissue studies-of extensive subclinical infection in the UK general population, although a further recent study has caused uncertainty over the significance of the previous studies. While definitive diagnosis of CJD is pathological, recent developments in protein amplification and detection have led to significantly better clinical diagnosis.

Sporadic and Infectious Human Prion Diseases

Human prion diseases are rare neurodegenerative diseases that have become the subject of public and scientific interest because of concerns about interspecies transmission and the unusual biological properties of the causal agents: prions. These diseases are unique in that they occur in sporadic, hereditary, and infectious forms that are characterized by an extended incubation period between exposure to infection and the development of clinical illness. Silent infection can be present in peripheral tissues during the incubation period, which poses a challenge to public health, especially because prions are relatively resistant to standard decontamination procedures. Despite intense research efforts, no effective treatment has been developed for human prion diseases, which remain uniformly fatal.

Prion Diseases

PURPOSE OF REVIEW

This article presents an update on the clinical aspects of human prion disease, including the wide spectrum of their presentations.

RECENT FINDINGS

Prion diseases, a group of disorders caused by abnormally shaped proteins called prions, occur in sporadic (Jakob-Creutzfeldt disease), genetic (genetic Jakob-Creutzfeldt disease, Gerstmann-Sträussler-Scheinker syndrome, and fatal familial insomnia), and acquired (kuru, variant Jakob-Creutzfeldt disease, and iatrogenic Jakob-Creutzfeldt disease) forms. This article presents updated information on the clinical features and diagnostic methods for human prion diseases. New antemortem potential diagnostic tests based on amplifying prions in order to detect them are showing very high specificity. Understanding of the diversity of possible presentations of human prion diseases continues to evolve, with some genetic forms progressing slowly over decades, beginning with dysautonomia and neuropathy and progressing to a frontal-executive dementia with pathology of combined prionopathy and tauopathy. Unfortunately, to date, all human prion disease clinical trials have failed to show survival benefit. A very rare polymorphism in the prion protein gene recently has been identified that appears to protect against prion disease; this finding, in addition to providing greater understanding of the prionlike mechanisms of neurodegenerative disorders, might lead to potential treatments.

SUMMARY

Sporadic Jakob-Creutzfeldt disease is the most common form of human prion disease. Genetic prion diseases, resulting from mutations in the prion-related protein gene (PRNP), are classified based on the mutation, clinical phenotype, and neuropathologic features and can be difficult to diagnose because of their varied presentations. Perhaps most relevant to this Continuum issue on neuroinfectious diseases, acquired prion diseases are caused by accidental transmission to humans, but fortunately, they are the least common form and are becoming rarer as awareness of transmission risk has led to implementation of measures to prevent such occurrences.

Autoimmune dementia and encephalopathy

Autoimmune dementia and encephalopathies (ADE) are complex disorders that can cause immune-mediated cognitive deficits and have confusing nomenclature. Presentation varies from acute limbic encephalitis to subacute or chronic disorders of cognition mimicking neurodegenerative dementia. It may occur as a paraneoplastic phenomenon or an idiopathic autoimmune phenomenon. The presence of a personal/family history of autoimmunity, inflammatory spinal fluid, serologic evidence of autoimmunity (neural or nonorgan-specific), or mesial temporal magnetic resonance imaging abnormalities are clues to diagnosis. Bedside cognitive assessment and/or detailed neuropsychologic testing are useful. Neural-specific autoantibodies, mostly discovered in the past two decades, may bind antigens on the cell surface (e.g., N-methyl-d-aspartate receptor autoantibodies) and are likely to be pathogenic, with treatment aimed at antibody-depleting agents often with success, while antibodies binding intracellular antigens (e.g., antineuronal nuclear autoantibody type 1 (ANNA1 or anti-Hu)) are a marker of a T-cell-mediated process and treated with T-cell-depleting immunotherapies, with variable responses. Detection and treatment of cancer (when present) are essential. High-dose corticosteroids are the initial treatment in most patients and may serve as a diagnostic test when the diagnosis is uncertain. Repeat cognitive testing after immunotherapy helps document objective improvements. Maintenance immunotherapy is recommended in those at risk for relapse. Prognosis is variable, but paraneoplastic ADE with antibodies to intracellular antigens have a worse prognosis. The field is still developing and future studies should provide guidelines for diagnosis and treatments.

Creutzfeldt-Jakob disease: updated diagnostic criteria, treatment algorithm, and the utility of brain biopsy

Creutzfeldt-Jakob disease (CJD) is a rare neurodegenerative condition with a rapid disease course and a mortality rate of 100%. Several forms of the disease have been described, and the most common is the sporadic type. The most challenging aspect of this disease is its diagnosis—the gold standard for definitive diagnosis is considered to be histopatho-logical confirmation—but newer tests are providing means for an antemortem diagnosis in ways less invasive than brain biopsy. Imaging studies, electroencephalography, and biomarkers are used in conjunction with the clinical picture to try to make the diagnosis of CJD without brain tissue samples, and all of these are reviewed in this article. The current diagnostic criteria are limited; test sensitivity and specificity varies with the genetics of the disease as well as the clinical stage. Physicians may be unsure of all diagnostic testing available, and may order outdated tests or prematurely request a brain biopsy when the diagnostic workup is incomplete. The authors review CJD, discuss the role of brain biopsy in this patient population, provide a diagnostic pathway for the patient presenting with rapidly progressive dementia, and propose newer diagnostic criteria.

Clinicopathological Correlations and Concomitant Pathologies in Rapidly Progressive Dementia: A Brain Bank Series

BACKGROUND

Rapidly progressive dementia (RPD) is caused by a heterogeneous group of both neurodegenerative and non-neurodegenerative disorders. The presence of concomitant pathologies, mainly Alzheimer's disease (AD), may act as a confounding variable in the diagnostic process of this group of diseases.

OBJECTIVES

We aimed to describe clinicopathological features, including Alzheimer's co-pathology, and diagnostic accuracy in a postmortem series of RPD.

METHODS

Retrospective analysis of 160 brain donors with RPD (defined as 2 years of disease duration from the first symptom to death) registered at the Neurological Tissue Bank of the Biobanc-Hospital Clínic-IDIBAPS, from 2001 to 2011.

RESULTS

Prion diseases were the most frequent neuropathological diagnosis (67%), followed by non-prion neurodegenerative pathologies (17%), mostly AD and dementia with Lewy bodies, and non-neurodegenerative diseases (16%). We observed clinicopathological diagnostic agreement in 94% of the patients with prion RPD but only in 21% of those with non-prion RPD. Four patients with potentially treatable disorders were diagnosed, while still alive, as having Creutzfeldt-Jakob disease. Concomitant pathologies were detected in 117 (73%). Among all RPD cases, 51 presented moderate or frequent mature β-amyloid plaques (neuritic plaques), which are considered to be associated with positive amyloid biomarkers in vivo.

CONCLUSIONS

Prion diseases were accurately identified in our series. In contrast, non-prion RPD diagnosis was poor while the patients were still alive, supporting the need for better diagnostic tools and confirmatory neuropathological studies. The presence of concomitant AD pathology in RPD should be taken into account in the interpretation of amyloid biomarkers.

[Creutzfeldt-Jakob disease: clinical and diagnostic aspects]

In this article, authors analyzed a modern approach to the diagnosis of Creutzfeldt-Jakob disease (CJD) based on the clinical signs, cerebrospinal fluid markers, electroencephalography and magnetic resonance imaging. It was demonstrated for the first time that patients with late-onset CJD differed from younger CJD patients with respect to MRI profiles and initial clinical presentation. To date, cerebrospinal fluid (CSF) analysis, particularly protein 14-3-3 testing, presents an important approach to the identification of disease cases. A spectrum of differential diagnosis of rapid progressive dementia varied from neurodegenerative dementias to dementia due to acute neurological conditions. Real-time quaking-induced conversion (RT-QuIC) allows the amplification of miniscule amounts of scrapie prion protein. Recent studies applied the RT-QuIC methodology to CSF for the diagnosis of human prion diseases.

Immunotherapy-responsive dementias and encephalopathies

The diagnosis of an autoimmune dementia requires the detection of objective improvements in cognitive decline (usually subacute in onset with a fluctuating course) after a course of immunotherapy. Serum and CSF antibody markers of autoimmunity (particularly those with neural antigen specificity) as well as other CSF markers of inflammation increase the suspicion for an autoimmune cause. The detection of neural autoantibodies should raise concern for a paraneoplastic etiology and may inform a targeted oncologic evaluation (eg, NMDA receptor antibodies are associated with teratoma). MRI, EEG, functional imaging, and neuropsychological evaluations provide objective evidence of neurologic dysfunction by which the success of immunotherapy may be measured. Most treatment information emanates from retrospective case series and expert opinion. Nonetheless, early intervention allows reversal of deficits in many patients. Chronic treatment is often required to maintain remission.

Rapidly progressive dementia: prion diseases and other rapid dementias

Dementias that occur over weeks to months require a different differential than the slowly progressive dementias that occur over years. Because of the rapidity of decline in cognition, the evaluation of the patient is usually urgent and requires an extensive workup with multiple tests running in parallel. Creutzfeldt-Jakob disease, perhaps the prototypic rapidly progressive dementia (RPD), is often the first diagnosis many neurologists consider when faced with a patient with rapid cognitive decline. Many conditions other than prion disease, however, can present with RPD. Other etiologies include autoimmune conditions, cancers, uncommon presentations of other more common neurodegenerative dementias, and others. This chapter discusses some of the major etiologies for RPDs and offers an algorithm for diagnosis. Some topics, such as other neurodegenerative dementias and autoimmune dementias, are covered in other chapters in this issue, and will be mentioned here only briefly.

Cerebrospinal fluid biomarker supported diagnosis of Creutzfeldt-Jakob disease and rapid dementias: a longitudinal multicentre study over 10 years

To date, cerebrospinal fluid analysis, particularly protein 14-3-3 testing, presents an important approach in the identification of Creutzfeldt–Jakob disease cases. However, one special point of criticism of 14-3-3 testing is the specificity in the differential diagnosis of rapid dementia. The constant observation of increased cerebrospinal fluid referrals in the national surveillance centres over the last years raises the concern of declining specificity due to higher number of cerebrospinal fluid tests performed in various neurological conditions. Within the framework of a European Community supported longitudinal multicentre study (‘cerebrospinal fluid markers’) we analysed the spectrum of rapid progressive dementia diagnoses, their potential influence on 14-3-3 specificity as well as results of other dementia markers (tau, phosphorylated tau and amyloid-β_1–42) and evaluated the specificity of 14-3-3 in Creutzfeldt–Jakob disease diagnosis for the years 1998–2008. A total of 29 022 cerebrospinal fluid samples were analysed for 14-3-3 protein and other cerebrospinal fluid dementia markers in patients with rapid dementia and suspected Creutzfeldt–Jakob disease in the participating centres. In 10 731 patients a definite diagnosis could be obtained. Protein 14-3-3 specificity was analysed for Creutzfeldt–Jakob disease with respect to increasing cerebrospinal fluid tests per year and spectrum of differential diagnosis. Ring trials were performed to ensure the comparability between centres during the reported time period. Protein 14-3-3 test specificity remained high and stable in the diagnosis of Creutzfeldt–Jakob disease during the observed time period across centres (total specificity 92%; when compared with patients with definite diagnoses only: specificity 90%). However, test specificity varied with respect to differential diagnosis. A high 14-3-3 specificity was obtained in differentiation to other neurodegenerative diseases (95–97%) and non-neurological conditions (91–97%). We observed lower specificity in the differential diagnoses of acute neurological diseases (82–87%). A marked and constant increase in cerebrospinal fluid test referrals per year in all centres did not influence 14-3-3 test specificity and no change in spectrum of differential diagnosis was observed. Cerebrospinal fluid protein 14-3-3 detection remains an important test in the diagnosis of Creutzfeldt–Jakob disease. Due to a loss in specificity in acute neurological events, the interpretation of positive 14-3-3 results needs to be performed in the clinical context. The spectrum of differential diagnosis of rapid progressive dementia varied from neurodegenerative dementias to dementia due to acute neurological conditions such as inflammatory diseases and non-neurological origin.

Diagnosis and treatment of rapidly progressive dementias

Rapidly progressive dementias are conditions that typically cause dementia over weeks or months. They are a particular challenge to neurologists as the differential diagnosis often is different from the more typical, slowly progressive dementias. Early and accurate diagnosis is essential, as many of the etiologies are treatable. The information in this review is in part based on experience through our rapidly progressive dementia program at the University of California San Francisco, Memory and Aging Center. As treatment of a rapidly progressive dementia is entirely dependent on the diagnosis, we present a comprehensive, structured, but pragmatic approach to diagnosis, including key clinical, laboratory, and radiologic features. For the 2 most common causes of rapid dementia, treatment algorithms for the autoimmune encephalopathies and symptomatic management for the neurodegenerative causes are discussed.

Cerebrospinal fluid markers in sporadic Creutzfeldt-Jakob disease

Sporadic Creutzfeldt-Jakob disease (sCJD) is the commonest form of human prion diseases, accounting for about 85% of all cases. Current criteria for intra vitam diagnosis include a distinct phenotype, periodic sharp and slow-wave complexes at electroencephalography (EEG), and a positive 14-3-3-protein assay in the cerebrospinal fluid (CSF). In sCJD, the disease phenotype may vary, depending upon the genotype at codon 129 of the prion protein gene (PRNP), a site of a common methionine/valine polymorphism, and two distinct conformers of the pathological prion protein. Based on the combination of these molecular determinants, six different sCJD subtypes are recognized, each with distinctive clinical and pathologic phenotypes. We analyzed CSF samples from 127 subjects with definite sCJD to assess the diagnostic value of 14-3-3 protein, total tau protein, phosphorylated₁₈₁ tau, and amyloid beta (Aβ) peptide 1-42, either alone or in combination. While the 14-3-3 assay and tau protein levels were the most sensitive indicators of sCJD, the highest sensitivity, specificity and positive predictive value were obtained when all the above markers were combined. The latter approach also allowed a reliable differential diagnosis with other neurodegenerative dementias.

Gerstmann-Sträussler-Scheinker syndrome masquerading as multiple sclerosis

Gerstmann-Sträussler-Scheinker syndrome (GSS) is a rare degenerative disorder of the central nervous system that belongs to the family of human spongiform encephalopathies, or prion diseases. GSS is almost always inherited and mostly carried in an autosomal dominant pattern. Nevertheless, GSS is genetically and phenotypically heterogeneous; among the different prion diseases GSS has the longest clinical course thereby has the potential to mimic the clinical course of different neurological disorders. Here, we report of a patient with a progressive ataxic syndrome, with MRI and CSF findings suggestive of a demyelinating-inflammatory process as multiple sclerosis and the cues that prompted to a final diagnosis of GSS.

Entzündliche Erkrankungen

Unter einer Meningitis versteht man eine Entzündung von Pia mater und Arachnoidea. Das Erregerspektrum ist weit und reicht von Bakterien, die hämatogen-metastatisch, fortgeleitet oder durch offene Hirnverletzung zur eitrigen Meningitis führen, über Viren zu Pilzen und Parasiten. Insbesondere bei den unbehandelt häufig letal verlaufenden eitrigen Meningitiden ist eine rasche Diagnose mit Erregernachweis notwendig. Unverzüglich ist daraufhin eine spezifische, der regionalen Resistenzentwicklung angepasste Therapie einzuleiten. Die meningeale Affektion im Rahmen einer Listeriose oder Tuberkulose verdient aufgrund des klinischen Bildes, des Verlaufs und der spezifischen Therapie besondere Beachtung. Die fungalen Infektionen werden, da klinisch häufig als Meningoenzephalitis imponierend, in Abschn. 33.3 abgehandelt.

Cerebrospinal fluid biomarkers in human prion diseases

Cerebrospinal fluid (CSF) is the main component of the brain extracellular space and participates in the exchange of many biochemical products in the CNS. Consequently, CSF contains a dynamic and complex mixture of proteins that reflect the physiological or pathological state of the CNS. Changes in the CSF proteome have been described in various neurodegenerative disorders. These alterations are also thought to reflect pathological changes in the brain, and thus understanding them will contribute to a better awareness of the pathophysiology that underlies these disorders. Proteomics offers a new methodology for the analysis of pathological changes and mechanisms occurring in neurodegenerative processes and provides the possibility of novel biomarker discovery in order to supplement faster, earlier and more precise diagnosis. In general, the following criteria have to be applied in order to qualify a protein or a gene as a potential biomarker: the selected parameters have to be sensitive (able to detect the abnormalities at early stage of disease), specific (to allow differential diagnosis), reproducible with a high positive predictive value, and should allow for disease monitoring as well as a potential therapeutic response. In Creutzfeldt–Jakob disease, two major approaches have been followed that aim to detect the pathological form of the prion protein (PrPSc) in various peripheral tissues, while other approaches look for surrogate parameters that are a consequence of the neurodegenerative process. While the amount of abnormal disease-related PrPSc in CSF and blood in human transmissible spongiform encephalopathies appears to be extremely low, the development of a PrPSc-based biomarker was hampered by technical problems and detection limits. However, a variety of other proteins have been investigated in the CSF, and recently a variety of potential biomarkers have been reported that contribute to clinical diagnosis. Already established markers are 14-3-3, β-amyloid, tau-protein and phosphorylated isoforms, S100b, as well as neuron-specific enolase. Since some of these markers display certain limitations, the search continues. This review summarizes current knowledge of biomarker development in prion diseases and discusses perspectives for new approaches.

Updated clinical diagnostic criteria for sporadic Creutzfeldt-Jakob disease

Several molecular subtypes of sporadic Creutzfeldt–Jakob disease have been identified and electroencephalogram and cerebrospinal fluid biomarkers have been reported to support clinical diagnosis but with variable utility according to subtype. In recent years, a series of publications have demonstrated a potentially important role for magnetic resonance imaging in the pre-mortem diagnosis of sporadic Creutzfeldt–Jakob disease. Magnetic resonance imaging signal alterations correlate with distinct sporadic Creutzfeldt–Jakob disease molecular subtypes and thus might contribute to the earlier identification of the whole spectrum of sporadic Creutzfeldt–Jakob disease cases. This multi-centre international study aimed to provide a rationale for the amendment of the clinical diagnostic criteria for sporadic Creutzfeldt–Jakob disease. Patients with sporadic Creutzfeldt–Jakob disease and fluid attenuated inversion recovery or diffusion-weight imaging were recruited from 12 countries. Patients referred as ‘suspected sporadic Creutzfeldt–Jakob disease’ but with an alternative diagnosis after thorough follow up, were analysed as controls. All magnetic resonance imaging scans were assessed for signal changes according to a standard protocol encompassing seven cortical regions, basal ganglia, thalamus and cerebellum. Magnetic resonance imaging scans were evaluated in 436 sporadic Creutzfeldt–Jakob disease patients and 141 controls. The pattern of high signal intensity with the best sensitivity and specificity in the differential diagnosis of sporadic Creutzfeldt–Jakob disease was identified. The optimum diagnostic accuracy in the differential diagnosis of rapid progressive dementia was obtained when either at least two cortical regions (temporal, parietal or occipital) or both caudate nucleus and putamen displayed a high signal in fluid attenuated inversion recovery or diffusion-weight imaging magnetic resonance imaging. Based on our analyses, magnetic resonance imaging was positive in 83% of cases. In all definite cases, the amended criteria would cover the vast majority of suspected cases, being positive in 98%. Cerebral cortical signal increase and high signal in caudate nucleus and putamen on fluid attenuated inversion recovery or diffusion-weight imaging magnetic resonance imaging are useful in the diagnosis of sporadic Creutzfeldt–Jakob disease. We propose an amendment to the clinical diagnostic criteria for sporadic Creutzfeldt–Jakob disease to include findings from magnetic resonance imaging scans.

Cerebrospinal Fluid

This chapter discusses the anatomy, functions, and biochemistry of cerebrospinal fluid (CSF). CSF has four major functions: physical support of neural structures, excretion and “sink” action, intracerebral transport, and control of the chemical environment of the central nervous system. CSF provides a “water jacket” of physical support and buoyancy. The CSF is protective because its volume changes reciprocally with changes in the volume of intracranial contents, particularly blood. Thus, the CSF protects the brain from changes in arterial and central venous pressure associated with posture, respiration, and exertion. Acute or chronic pathological changes in intracranial contents can be accommodated, to a point, by changes in the CSF volume. The direct transfer of brain metabolites into the CSF provides excretory function. This capacity is important because the brain lacks a lymphatic system. The lymphatic function of the CSF is also manifested in the removal of large proteins and cells, such as bacteria or blood cells, by bulk CSF absorption. The “sink” action of the CSF arises from the restricted access of water-soluble substances to the CSF and the low concentration of these solutes in the CSF.