Dementia



Dementia


Joel Salinas

Vikram Khurana



GENERAL INFORMATION

Definition: (1) Acquired loss of cognitive abilities or comportment w/impairment of ≥2 of: (a) Memory (ability to learn new information or recall previously learned information). (b) Language. (c) Executive function (planning, organizing, sequencing, or related abilities). (d) Visuospatial abilities. (e) Gnosis (recognition/identification of objects or people, w/intact elementary sensation). (f) Praxis (ability to do skilled motor tasks, w/intact elementary sensorimotor function). (g) Other intellectual abilities (e.g., calculation). (h) Social/emotional abilities (e.g., regulating drives; interacting appropriately). (2) Preserved elements of basic attention (i.e., absence of encephalopathy). (3) Compromises complex activities of daily living (ADLs), social or occupational function. May be subdivided based on time course: Chronic dementia: Progresses over months to years. Rapidly progressive dementia: Subacute time course of weeks to months.

Delirium distinguished from dementia based on: impaired attention, rapid onset (hours to days), fluctuating course. However, some dementias can have prominent fluctuations in attention, such as dementia w/Lewy bodies (see below). Mild cognitive impairment (MCI) & normal aging distinguished from dementia based on impact on ADLs (see below).

Epidemiology: Aging: Most significant known risk factor (i.e., age mainly >65), relatively rare hereditary & acquired forms. Affects >5 million Americans (1 in 9 above 65, 1 in 3 above 85). Cost > $200 billion annually (2014 Alzheimer’s Dz Facts & Figures).

Etiology: Most common cause is sporadic Alzheimer dz (AD) (60%-80% of demented pts in the United States). Multiple etiologies in same pt common (e.g., mixed Alzheimer’s/vascular dementia). Other causes: Prion dzs, Hashimoto encephalopathy → see rapidly progressive dementia. Dementias w/movement d/o as salient clinical feature → see chapter Movement Disorders. Pediatric dementias: Most common = neuronal ceroid lipofuscinoses. See Pediatrics chapter. Dementia from paraneoplastic syndromes → see Neuro-Oncology chapter Paraneoplastic Syndromes.














Causes of Dementia


Idiopathic late-onset


AD, dementia a/w parkinsonism (dementia w/Lewy bodies [DLB], Parkinson disease dementia [PDD], progressive supranuclear palsy [PSP], corticobasal syndrome), frontotemporal dementia (FTD) spectrum disorders, prion diseases


Familial


Adult onset: Familial forms of AD, FTD, extrapyramidal (e.g., familial parkinsonism, Huntington disease, Wilson disease), prion dzs, Down syndrome, Kufs disease


Pediatric: Neuronal ceroid lipofuscinoses, storage diseases, adrenoleukodystrophies


Toxic


Alcohol, metals (e.g., heavy metals, aluminum/dialysis dementia), carbon monoxide, radiation-induced


Metabolic


Vitamin deficiencies (e.g., B1, B12, nicotinic acid), chronic endocrinopathies (hypothyroidism, adrenal insufficiency, parathyroid disease). Chronic metabolic disturbance (chronic renal disease, chronic liver disease, chronic anoxic states, mitochondrial disorders)

Infectious


Prion diseases, AIDS dementia complex, syphilis, progressive multifocal leukoencephalopathy (PML, due to JCV)


Inflammatory


Vasculitis, multiple sclerosis, paraneoplastic, Hashimoto encephalopathy


Neoplastic


Primary CNS tumor, gliomatosis cerebri, metastatic CNS tumor, primary CNS or systemic non-Hodgkin lymphoma


Vascular


Diffuse (Binswanger disease), vascular dementia


Traumatic


Chronic subdural hematoma, chronic traumatic encephalopathy (dementia pugilistica)


Other


Recurrent nonconvulsive seizures, chronic refractory epilepsy, NPH



APPROACH TO DIAGNOSIS OF DEMENTIA


HISTORY

Careful history from pt & family members. Determine symptoms w/special care. Initial sx esp important. Consider the following domains: (1) Cognitive (such as memory, language, praxis). (2) Neurobehavioral (motivation, sleep, appetite). (3) Neuropsychiatric (mood, hallucinations, delusions). (4) Functional consequences (ADLs). (5) Other neurologic (abnl movements, falls, imbalance). (6) Temporal course: Rapidity of onset, course—progressive? fluctuating? stepwise? (7) Nonneurologic sxs, e.g., fever, wt loss, cardiorespiratory, rash. (8) PMH may suggest potential etiologies (Fig. 12.1). (9) Medications. (10) Family history may give clue to familial dementias. (11) Social history may be revealing (e.g., smoking → vascular dementia/chronic pulmonary dz, alcohol abuse → alcohol & nutritional deficiency-related dementias, multiple sexual partners → HIV or syphilis).



EXAMINATION

Divided into mental status, neurologic & general medical examination.

General medical: Critical to identifying neuromedical causes of dementia.

Mental status: Including orientation; attention; memory; language; executive function; praxis; visuospatial and intellectual function.

Standardized tests can be useful, including the Mini-Mental State examination (Se for dementia ˜70%; Sp ˜90%) & Montreal cognitive assessment (MoCA; more Se but less Sp for MCI; normative data avail at http://www.mocatest.org) tools. Queen Square Screening Test for Cognitive Deficits is useful pocket-sized companion (Warrington EK. The Queen Square Screening Test for Cognitive Deficits. London, UK: Institute of Neurology, 1989).

General neurologic: CN, motor, sensory, reflexes, cerebellar, gait.

Neuropsychological assessment: Standardized testing by neuropsychologist: Determine pattern & degree of deficits in different cognitive domains; helps in evaluation to assess mood, psychosis, cooperation.


DIAGNOSTIC STUDIES

Laboratory tests: Consider the following lab tests but tailor to individual pts: Basic (chem10, BUN/Cr, LFTs, Ca/PO4, CBC, PT/INR, PTT, ESR/CRP), endocrine studies (hemoglobin A1c, TSH), metabolic (fasting lipid panel, vitamin B12), infectious (syphilis serology, HIV), lumbar puncture (including Aβ/tau). Other laboratory studies dictated
by history & examination (e.g., rheumatologic, vasculitic labs; tox screens; paraneoplastic). Nonlaboratory tests to r/o medical illness as indicated (e.g., EKG, CXR, TTE).

Neuroimaging: Structural imaging: Brain MRI preferable to head CT w/contrast. Vascular imaging (in cases of suspected vascular dementia). Functional imaging: SPECT (single photon emission computed tomography) & PET measure resting cerebral blood flow & metabolism. Chemical imaging: MR spectroscopy; amyloid/tau PET imaging, not yet in widespread clinical use.

Other testing: EEG (e.g., suspected CJD, nonconvulsive seizure disorder), EMG/NCS (suspected motor neuron dz), cerebral angiography (suspected CNS vasculitis), brain bx (uncertain dx). Genetic testing, e.g., tests for Huntington dz, familial Parkinson dz, spinocerebellar ataxia.






















































Clinical Differentiation of the Major Dementias


Dz

First Sx

Mental Status exam

Φ sxs

Neuro exam

Imaging/Biomarkers


AD

Memory loss (in majority of cases), though other cognitive, behavioral sxs can be 1st

Usu episodic memory loss, though other cog domains can be impaired

Usu nl, though apathy/depression are common

Initially nl

Entorhinal cortex & hippocampal atrophy; T/P atrophy or ↓ metabolism; + amyloid PET, CSF ↓ Aβ + ↑ tau


FTD

Apathy, poor judgment/insight, speech/language

Frontal/executive, language; spares v/s

Apathy, disinhibition, hyperorality, loss of empathy, perseverations/compulsions

Due to PSP/CBD overlap: Vertical gaze palsy, axial rigidity, dystonia, alien hand


Concurrent motor neuron disease

FL &/or TL atrophy or ↓ metabolism; spares posterior PL


DLB

Visual hall., REM sleep d/o, fluctuations parkinsonism, attention, v/s deficits

& frontal/executive; spares memory early; delirium prone

Visual hall. depression sleep d/o delusions

Parkinsonism

Posterior PL atrophy; OL ↓ metabolism or ↓ perfusion


CJD

Dementia, mood, anxiety, mvmt d/o, visual symptoms

Variable

Depression, anxiety

Myoclonus, rigidity, parkinsonism, cortical blindness

Cortical ribboning, BG, or thalamus: hyperintensity on DWI/FLAIR MRI


Vascular

Variable: apathy, judgment/problemsolving difficulty; falls, focal weakness

Frontal/executive, cognitive slowing; can spare memory

Apathy, depression

Usually motor slowing, spasticity; can be normal

Cortical &/or subcortical infarctions, confluent WM dz


Adapted from Bird TD, Miller BL. Alzheimer’s disease and primary dementias. In: Fauci AS, Braunwald E, Kasper DL, et al., eds. Harrison’s Principles of Internal Medicine. 17 ed. New York, NY: McGraw-Hill, 2008:2393-2406.




TREATMENT OF DEMENTIA

Disease-modifying pharmacotherapy: None available; some promising agents in trial.

Symptomatic pharmacotherapy: Cholinesterase inhibitors for AD & DLB. NMDA receptor antagonists for AD. Antidepressants for depression, anxiety. Neuroleptics for agitation, psychosis (typically use atypical neuroleptics (e.g., preferably quetiapine [Seroquel] given less EPS compared to other atypicals); for acute severe agitation requiring parenteral medication, consider IV or IM Haldol); can cause significant adverse reaction in DLB. Stimulants, catecholamine enhancers, dopaminergic agonists for inattention (limited data), ↓ arousal, apathy. Antiseizure medications for mood stabilization (limited data).

Treat comorbid medical disorders: May be potentiating cognitive decline. Control of vascular risk factors (smoking cessation, lipids, diabetes); treat liver & renal dz; correct vision & hearing (glasses, hearing aids); replace B12 if borderline low.

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Aug 17, 2016 | Posted by in NEUROLOGY | Comments Off on Dementia

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