Article

The Evaluation of Rapidly Progressive Dementia

Bedford VA Hospital, Geriatric Research and Education Clinical Center (GRECC), Bedford.
The Neurologist (Impact Factor: 1.16). 03/2011; 17(2):67-74. DOI: 10.1097/NRL.0b013e31820ba5e3
Source: PubMed

ABSTRACT

Rapidly progressive dementia (RPD) is a unique set of disorders resulting in cognitive, behavioral, and motor decline within 2 years. A variety of etiologies may contribute to RPD including neurodegenerative, inflammatory, infectious, and toxic-metabolic conditions. Jakob-Creutzfeldt disease (CJD) is frequently the most concerning diagnosis on the differential. The challenge for the neurologist is distinguishing prion disease from reversible processes that result in dementia.
This review discusses the clinical aspects and the diagnostic workup of RPD. Particular focus is given to both CJD and the potentially treatable inflammatory conditions that may cause a similar presentation. Furthermore, a standardized stepwise approach is outlined for patients presenting with RPD.
Neurologists should adopt a standardized approach to the rapidly presenting disease processes that may mimic CJD in their clinical and radiologic features.

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    • "Patients with a diagnosis of RPD were included in the study. The diagnosis of RPD was made according to the following definition: cognitive, behavioral, or motor impairment with a disease course of less than 24 months from first reported symptom to functional dependence [4]. Other inclusion criteria were: 1) a follow-up period of at least 12 months after the first neurological assessment or a shorter period when pathological diagnosis was available; 2) a complete minimum data-set of investigations which are requested in the diagnostic work-up of RPD as first line exams (routine blood analysis including thyroid hormones and Vitamin B12 dosage, brain computed tomography or MRI scan, standard CSF analysis) [1]. "
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    ABSTRACT: Rapidly progressive dementia (RPD) is a rare presentation of different neurological disorders characterized by cognitive impairment leading to loss of functional independence within 24 months or less. The increasing recognition of treatable non-prion causes of RPD has made the differential diagnosis with sporadic Creutzfeldt-Jakob disease (sCJD) of crucial importance. We therefore assessed the frequency of different etiologies of RPD and evaluated the accuracy of newly proposed diagnostic criteria for sCJD. Clinical records of patients with RPD referred to Memory Clinic between 2007 and 2012 were retrospectively analyzed. The accuracy of diagnostic criteria for sCJD was evaluated by: a) MRI images in DWI and FLAIR sequences; and (b) CSF 14-3-3 protein. In addition, CSF total tau protein level was also assessed. Final diagnosis was obtained after a 1-year follow-up or after autopsy. Among 37 patients with RPD, the most frequent causes were non-prion diseases, either untreatable (38%) or potentially treatable (32%), thus leaving sCJD as a less frequent cause (30%). DWI images had a sensitivity of 73% and specificity of 96%, while FLAIR yielded a very low sensitivity (40%). CSF 14-3-3 protein had a sensitivity of 100%, but a very low specificity (43%). The strongest independent predictor of sCJD diagnosis was the CSF tau level (p = 0.002) (91% sensitivity, 83% specificity). Treatable causes of RPD are as frequent as sCJD and a rapid differential diagnosis is mandatory. We suggest that DWI images and CSF analysis combining 14-3-3 and total tau protein determination hold the best informative diagnostic values.
    No preview · Article · Dec 2012 · Journal of Alzheimer's disease: JAD
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    ABSTRACT: While the most common dementia is Alzheimer disease (AD), a detailed history is needed to rule out rapidly progressive dementias (RPDs). RPDs are less than two years in duration and have a rate of progression faster typical neurodegenerative diseases. Identification of RPDs is important as some are treatable. This review focuses on the spectrum of RPDs, with special emphasis on paraneoplastic disorders and Creutzfeldt-Jakob disease (CJD).
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    ABSTRACT: Although no precise definition for rapidly progressive dementia (RPD) exists, this term is generally used to refer to cases with significant and progressive cognitive impairment that occurs over weeks or months. RPD represents an unusual but severe condition that causes distress not only for patients and their relatives but also for the clinicians involved, as multiple investigations and decisions about management must be made urgently to avoid misdiagnosing a treatable condition and to preserve as much of the neural tissue as possible from definite damage. While Creutzfeldt-Jacob disease (CJD) has for a long period of time been regarded as the prototype of RPD, this infrequent but severe condition can be produced by an extensive variety of causes such as various endocrine, metabolic or toxic disorders, central nervous system (CNS) infections, primary or secondary CNS neoplasms, various CNS vasculitides and various autoimmune conditions in which autoantibodies against neural tissue are produced, whether in the presence of a neoplasm or not. However, even in the more common and usually slowly progressive dementias such as Alzheimer's disease, frontotemporal lobar degeneration, dementia with Lewy bodies and other degenerative dementias, as well as vascular dementia, establishment and progression of the disease is occasionally surprisingly accelerated, leading to a clinical presentation of RPD. The few published case series of RPD have shown that the relative frequency of underlying diseases depends mainly on the clinical setting. Thus, CJD has been found to be the most prevalent cause in referral centres for spongiform encephalopathies, while secondary causes are more prevalent in general referral centres for dementia diagnosis. In clinical practice, for the cases presenting with RPD, the diagnostic procedure must be exhaustive, starting with a detailed clinical evaluation and proceeding to a complete laboratory work-up and sophisticated neuroimaging studies. There has been recent enormous progress in imaging, with sensitive new sequences of magnetic resonance imaging and immunology; as a result, a plethora of antibodies against the CNS can now be detected in cases of autoimmune dementias, which has dramatically changed the diagnostic approach and early management of cases of RPD. The same favourable effect in clinical practice comes from the accumulated knowledge of the complex clinical picture of various causes of RPD, associated specific neurological features (pyramidal signs, ataxia, myoclonus) and systematic features (weight loss, hyponatraemia, hepatic disorders) and their mode of progression. The term rapidly progressive dementia (RPD) is used to describe cases with a progression course which usually ranges between weeks and months. 1–4 The subacute nature of RPD excludes other conditions with fulminant progression such as infectious or metabolic acute encephalopathies, which progress within hours or days and typically commence as an acute confusional state. In most cases, the cognitive decline observed in RPD can be attributed to a single underlying disorder. Nevertheless, a rapid course might also represent the aggravation of an undiagnosed disease attributable to a secondary cause, usually an infection or a metabolic dysregulation. Various conditions involving the central nervous system (CNS) can emerge as RPD, including Creutzfeld-Jakob disease (CJD) and other spongiform encephalopathies, vascular disorders, autoimmune and paraneoplastic encephalopathies, subacute infections, metabolic and toxic disorders and systemic diseases (see Table 1). However, it is important to point out that even neurodegenerative disorders such as Alzheimer's disease (AD), dementia with Lewy bodies and frontotemporal dementia present in rare cases as a subacute dementia instead of a slowly progressive deterioration of higher functions. 5 CJD is the prevailing cause of RPD in most related studies. Regarding the relative frequency of other disorders which account for cases of RPD, there is marked variability among scientific groups. 1–3 In cases of RPD with an early age of onset, the possibility of an infection, hereditary metabolic disorder or autoimmune encephalopathy should be considered. 6,7 The early diagnosis of the undergoing disorder in a patient exhibiting an RPD can be particularly demanding owing to the paucity of clinical signs during the early stages of many disorders and to overlapping laboratory findings. The pattern of cognitive deficits is crucial for clinical assessment. Selective memory, executive function and language deficits might favour one potential diagnosis and exclude others. Thus, a detailed neuropsychological evaluation is crucial. 2,3
    Full-text · Article · Jan 2011 · European Review
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