Rapidly progressive young-onset dementias: neuropsychiatric aspects

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.

CCCDTD5: Clinical role of neuroimaging and liquid biomarkers in patients with cognitive impairment

Since 1989, four Canadian Consensus Conferences on the Diagnosis and Treatment of Dementia (CCCDTDs) have provided evidence-based dementia diagnostic and treatment guidelines for Canadian clinicians and researchers. We present the results from the Neuroimaging and Fluid Biomarkers Group of the 5th CCCDTD (CCCDTD5), which addressed topics chosen by the steering committee to reflect advances in the field and build on our previous guidelines. Recommendations on Imaging and Fluid Biomarker Use from this Conference cover a series of different fields. Prior structural imaging recommendations for both computerized tomography (CT) and magnetic resonance imaging (MRI) remain largely unchanged, but MRI is now more central to the evaluation than before, with suggested sequences described here. The use of visual rating scales for both atrophy and white matter anomalies is now included in our recommendations. Molecular imaging with [18F]-fluorodeoxyglucose ([18F]-FDG) Positron Emisson Tomography (PET) or [99mTc]-hexamethylpropyleneamine oxime/ethylene cysteinate dimer ([99mTc]-HMPAO/ECD) Single Photon Emission Tomography (SPECT), should now decidedly favor PET. The value of [18F]-FDG PET in the assessment of neurodegenerative conditions has been established with greater certainty since the previous conference, and it has now been recognized as a useful biomarker to establish the presence of neurodegeneration by a number of professional organizations around the world. Furthermore, the role of amyloid PET has been clarified and our recommendations follow those from other groups in multiple countries. SPECT with [123I]-ioflupane (DaTscanTM) is now included as a useful study in differentiating Alzheimer's disease (AD) from Lewy body disease. Finally, liquid biomarkers are in a rapid phase of development and, could lead to a revolution in the assessment AD and other neurodegenerative conditions at a reasonable cost. We hope these guidelines will be useful for clinicians, researchers, policy makers, and the lay public, to inform a current and evidence-based approach to the use of neuroimaging and liquid biomarkers in clinical dementia evaluation and management.

The speed of progression towards obsessive-compulsive disorder

BACKGROUND

There is current interest in the elaboration of early intervention programs for obsessive-compulsive disorder (OCD). To this end, it is important to investigate the speed of progression from subthreshold symptoms to diagnosable OCD. In this study, we have retrospectively investigated the speed of progression towards full-blown OCD and sociodemographic and clinical factors associated with a faster transition.

METHODS

Patients enrolled in the Brazilian Research Consortium on Obsessive-Compulsive Spectrum Disorders (N = 954) were interviewed with a comprehensive assessment battery that included the interval (in years) between the onset of subthreshold OCD symptoms and the onset of full-blown OCD.

RESULTS

It took a median of 7 years (interquartile range: 2-13 years) for subthreshold symptoms to convert to diagnosable OCD. Faster OCD onset was associated with lower age at the time of assessment, male gender, being in new romantic states as precipitants for compulsions, greater severity of sexual/religious symptoms and lower severity of hoarding and YBOCS compulsions severity scores, greater rates of generalized anxiety disorder and agoraphobia without panic disorder, and negative family history for OCD.

LIMITATIONS

The retrospective design of this study allowed for susceptibility to memory bias about age at onset of OCD symptoms. We were unable to capture progressions taking less than 12 months.

CONCLUSIONS

We could identify a specific phenotype that was more likely to escalate rapidly to clinical levels within this large clinical sample. This phenomenon may be particularly relevant in the context of selecting individuals for early intervention initiatives in situations when resources are scarce.

An Evaluation of Rapidly Progressive Dementia Culminating in a Diagnosis of Creutzfeldt-Jakob Disease

Rapidly progressive dementia is a curious and elusive clinical description of a pattern of cognitive deficits that progresses faster than typical dementia syndromes. The differential diagnosis and clinical workup for rapidly progressive dementia are quite extensive and involve searching for infectious, inflammatory, autoimmune, neoplastic, metabolic, and neurodegenerative causes. We present the case of a previously highly functional 76-year-old individual who presented with a 6-month history of rapidly progressive dementia. His most prominent symptoms were cognitive impairment, aphasia, visual hallucinations, and ataxia. Following an extensive battery of tests in hospital, the differential diagnosis remained probable CJD versus autoimmune encephalitis. He clinically deteriorated and progressed to akinetic mutism and myoclonus. He passed away 8 weeks after his initial presentation to hospital, and an autopsy confirmed a diagnosis of sporadic CJD. We use this illustrative case as a framework to discuss the clinical and diagnostic considerations in the workup for rapidly progressive dementia. We also discuss CJD and autoimmune encephalitis, the two main diagnostic possibilities in our patient, in more detail.

Caregivers' Perspectives of Quality of Life of People With Young- and Late-Onset Alzheimer Disease

BACKGROUND

Quality of life (QoL) is a growing area of interest in dementia research. This study aims to investigate the caregivers' perspective about the QoL of people with young-onset Alzheimer disease (YOAD) and late-onset Alzheimer disease (LOAD). We also aim to investigate factors that might be associated to caregivers' perspective in YOAD and LOAD.

METHODS

We included 110 people with Alzheimer disease (PwAD; 53 YOAD) and their primary caregivers. The PwAD completed assessments about their QoL and cognition. The caregivers provided information about the PwAD (demographics, QoL, ability to perform activities of daily living, mood, and dementia severity) and had burden of care assessed.

RESULTS

We did not find a difference in caregivers' perspectives of PwAD QoL according to the age at onset. However, the linear regression analysis indicated that caregivers' burden ( P < .01) and PwAD depressive symptoms ( P < .05) were significantly related to the caregivers' perspective of YOAD QoL. Caregivers' burden ( P < .01), years of education ( P < .05), and self-reported QoL ( P < .01) were significantly related to the caregivers' perspective of LOAD QoL.

CONCLUSIONS

The factors that drive the perceptions of caregivers of PwAD QoL may vary according to the age at onset. The study provides basic information on caregivers' perspectives of PwAD QoL to create more effective interventions according to the age at onset.

Symptomatic treatment, care, and support of CJD patients

Prion diseases (e.g., Creutzfeldt-Jakob disease) are rapidly progressive neurodegenerative diseases that are invariably fatal. Diagnosing prion disease can be difficult and can lead to frustration. There is no currently available disease-altering treatment for prion diseases and the care and management of affected patients are directed towards symptomatic relief and quality of life. In this chapter, we highlight the many unique challenges of prion disease and how they affect care and management strategies. Symptomatic treatment follows many of the same principles observed in geriatric and/or hospice care, with some important differences due to disease-specific characteristics. We provide an overview of pharmacologic and nonpharmacologic strategies for managing symptoms of prion disease. Education and psychosocial support are also very important in managing patients and families affected by the illness and are discussed in detail. Readers of this chapter will understand the context of caring for a patient with prion disease and will be supplied with practical tools for managing symptoms and educating other healthcare personnel and caregivers. Additional resources for assistance in the care of prion disease patients are also discussed.

Distinct prion-like strains of amyloid beta implicated in phenotypic diversity of Alzheimer's disease

Vast evidence on human prions demonstrates that variable disease phenotypes, rates of propagation, and targeting of distinct brain structures are determined by unique conformers (strains) of pathogenic prion protein (PrP(Sc)). Recent progress in the development of advanced biophysical tools that inventory structural characteristics of amyloid beta (Aβ) in the brain cortex of phenotypically diverse Alzheimer's disease (AD) patients, revealed unique spectrum of oligomeric particles in the cortex of rapidly progressive cases, implicating these structures in variable rates of propagation in the brain, and in distict disease manifestation. Since only ∼30% of phenotypic diversity of AD can be explained by polymorphisms in risk genes, these and transgenic bioassay data argue that structurally distinct Aβ particles play a major role in the diverse pathogenesis of AD, and may behave as distinct prion-like strains encoding diverse phenotypes. From these observations and our growing understanding of prions, there is a critical need for new strain-specific diagnostic strategies for misfolded proteins causing these elusive disorders. Since targeted drug therapy can induce mutation and evolution of prions into new strains, effective treatments of AD will require drugs that enhance clearance of pathogenic conformers, reduce the precursor protein, or inhibit the conversion of precursors into prion-like states.

A young-onset frontal dementia with dramatic calcifications due to a novel CSF1R mutation

Neuroimaging and genomic analysis greatly aid in the identification of young-onset dementia antemortem. We present the case of a 33-year-old female with a 2-year rapid decline to dementia and immobility marked by personality change, executive deficits including compulsions, attention deficit, apraxia, Parkinsonism, and pyramidal signs. She had unique and dramatic calcifications and confluent white matter changes on imaging and was found to have a novel mutation in the colony stimulating factor 1 receptor gene causing adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP). Here, we review ALSP and briefly discuss differential diagnoses.