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The Dementias William S. Woodfin, M.D. Neurology Specialists of Dallas Clinical Assoc. Prof. of Neurology UT Southwestern Medical School. Definition. Dementia:The development of multiple cognitive deficits suffficiently severe to cause impairment in occupational or social functioning
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The DementiasWilliam S. Woodfin, M.D.Neurology Specialists of DallasClinical Assoc. Prof. of NeurologyUT Southwestern Medical School
Definition • Dementia:The development of multiple cognitive deficits suffficiently severe to cause impairment in occupational or social functioning • Mild Cognitive Impairment: usually refers to a single cognitive domain
Classification • Alzheimer’s Disease: Sporadic v. Familial • Parkinson Syndromes • Fronto-Temporal Lobar • Vascular • Infectious • Metabolic • Pseudodementia • Others
DEMENTIA SYNDROMES Normopressure Hydrocephalus Vascular Parkinsonism Multiple System Atrophy FXTAS Alzheimer’s Disease Lewy Body Parkinson’s Disease Supranuclear Palsy Diffuse Lewy Body Disease Corticobasalganglionic Degeneration Fronto-temporal Dementia Amyloid and Tau α-SYNUCLEINOPATHIES TAUOPATHIES
Alzheimer’s • History: Alois Alzheimer 1906 • Epidemiology: * 4 million pts. • * A disease of advancing age but not normal aging. Loss vs. shringage of neurons • * Age 60 1% • Age 85 30-50% • * Underdiagnosed • * Women more than men • * Cost $110 billion
Development of multiple cognitive deficits manifested by both memory impairment (amnesia) and 1 or more of the following cognitive disturbances: aphasia, apraxia, agnosia, or disturbance in executive functioning (abstractions) Cognitive deficits cause significant impairment in social functioning and represent a significant decline from a previous level of functioning Course is gradual in onset with continuingcognitive decline Deficits are not due to any other CNS disorder, systemic illness, or substance-induced condition Deficits do not occur exclusively during the courseof delirium DSM-IV Definition of Alzheimer’s Disease Source: Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Washington, DC: American Psychiatric Association; 1994:85-86.
Alzheimer’s Disease (AD): More Than Just Memory Loss • AD is a progressive, degenerative disease involving: • A Decline in ability to perform activities of daily living • B Changes in personality and behavior • C Loss of memory and other cognitive functions • D Eventual nursing home placement, death $ Increases in resource utilization
Progression of Alzheimer's Disease Early Diagnosis Mild-Moderate Severe 30 Cognitive Symptoms 25 20 Loss of ADLs MMSE score 15 Behavioral Problems 10 Nursing Home Placement 5 Death 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 Years Feldman H, Gracon S. In: Clinical Diagnosis and Management of Alzheimer’s Disease. 1996, 239-253.
Apolipoprotein E • ε 4 allele: a “susceptibility gene” on chromosome 19 • single copy→ 2-3 x risk, double copy→ 5 x risk • lowers age of onset • may be assoc. c clearing of Aβ- increased plaques, • but no increase in NFTs • ε 2 allele appears protective • “Not necessary or sufficient”- ½ of AD pts. don’t have • the allele, 10-20% of normal older adults carry one or • two
Gross Pathology Temporal lobes esp. hippocampus & entorhinal cortex. Olfactory bulbs and tracts Parietal lobes Subcortical nuclei that project to the cortex: Nucleus Basalis of Meynert (AcH) Locus ceruleus (NE) Raphae nuclei (Serotonin)
Neuropathologic ChangesCharacteristic of Alzheimer’s Disease Normal AD NORMAL ALZHEIMER’S AP NFT EXTRACELLULAR INTRACELLULAR AP = amyloid plaques. NFT = neurofibrillary tangles. Courtesy of Albert Enz, PhD, Novartis Pharmaceuticals Corporation. 6
Microscopic Pathology • Amyloid (Senile) Plaques: Extraneuronal • Aβ • Dystrophic axons and dendrites • Astrocytes • Microglia • Neurofibrillary Tangles: Intraneuronal- predominantly • axonal, longer axons • Hyperphosphorylated tau protein • Neuronal loss • Vascular change: Cerebral Amyloid Angiopathy • Aβ 40
Etiology: Amyloid Hypothesis • Cleavage of transmembranous APP by secretases • Aβ 40 & Aβ 42 • Insoluble oligomers • Insoluble fibrils • Diffuse plaque • Mature plaque- due to inflammatory reaction with astrocytes and microglia • Neuronal and synaptic injury • NFTs and Neuronal death • Loss of neurotransmitters
Evidence for the Amyloid Hypothesis • Aβ neurotoxic in vitro • Overexpression of APP in transgenic mice=disease • Mutations in APP = early onset disease • All known mutations= increased Aβ • Downs Syndrome with 3 copies of APP gene • Apolipoprotein E € 4 accelerated Amyloid deposition • Amyloid antibodies in mice and men slows disease
Familial Alzheimer’s • Chromosome 14 c presenilin 1 gene • Chromosome 1 c presenilin 2 gene • Both code for a portion of γ-secretase • Chromosome 21 c APP mutations • Onset of sxs. In 40s & 50s
Tau Association With Microtubules Hyperphosphorylated tau subunits Tau bound to microtubule Microtubule PHF composed of tau subunits PHF = paired helical filaments.
Prevention • Anti-Inflammatories • Hormones • Vitamins and Herbs • Diet and Antioxidants • Alcohol and Smoking • Exercise • Basic Medical Care • Blood Pressure • Lipids • Homocystine • Specific Agents • Cholinesterase Inhibitors • NMDA Receptor Blockers
Anti-Inflammatories • Dutch study, NEJM 2001: RR 0.95 < 1 month • 0.83 1-24 months • 0.20 > 2 years • No benefit with trials of: Prednisone • Diclofenac • Rofecoxib • Naproxen
Estrogens • Mechanisms: Estrogen receptors associated with NGF receptors • May enhance neurotransmitter function, esp. Ach • May diminish excitatory effect of Aβ • May alter APP resulting in less Aβ • PET shows increased blood flow and glucose metabolism in hippocampus • Early studies mixed: Prior to 1999, 4 impairment, 7 improvement • WHIMS: Estrogen & Progesterone: Mild increase in stroke and dementia • Estrogen alone: stopped this year, risk of dementia about the same • Would earlier institution of estrogens or longer duration of treatment be useful? Cache Co. Utah study
Vitamins and Herbs • Vitamin E- No help • Potential toxicity: bleeding, HA,N,V,diarrhea, bone pain, hair loss • Vitamin C- No compelling evidence • Folic Acid- Increasing evidence for protection for AD and VaD • Would use more than 400 mcgm/day • Ginko Biloba- several studies suggest some improvement • St. Johns Wort- caution
Diet & Antioxidants • Fats: Diets high in unsaturated, unhydrogenated fats and low in saturated/transunsaturated fats may protect against dementia and coronary disease. • Cholesterol: Mixed findings. Dietary cholesterol has less impact on serum cholesterol than does saturated fat intake. • Dietary Flavinoids: May diminish risk • Caloric Intake: Animal studies show all degenerative diseases associated with aging diminish with reduced caloric intake. • Increased oxidative stress and accumulation of free radicals.
Alcohol & Smoking • Red Wine: 250-500 ml/day may protect • May be due to flavanoids, also found in tea,fruit, and vegetables. • Beer: May worsen odds with low intake of thiamine and other B vitamins • Dangers in the elderly: Lean body mass • Trauma • Interactions with medications • Smoking: Accelerates microvascular cerebral disease
Exercise • Physical: Decreases glucose and LDL levels, raises HDL • Aerobic vs. anaerobic and frontal lobe function • Mental: Educational attainment • Ongoing cognitive efforts: Nun study- Top 10% were 47% less likely than bottom 10% to become demented. • Sensory support: eyeglasses, hearing aids
Basic Medical Care • Control of blood pressure and glucose • Statins: Inhibit activity of β and γ secretase • May limit effects of APO € 4 allele • Endothelial remodeling • Increase e NOS • Decrease endothelin-1 • PROSPER study (Pravastatin) • HPS study (Simvastatin) • Atorvastatin
Specific Pharmaceutical Intervention • Cholinesterase Inhibitors: Donepezil (Aricept) • Rivistigmine (Exelon) • Galantamine (Reminyl→Razadyne)) • NMDA Inhibitors: Memantine (Namenda) • Considerations in their use: Cognition • Behavior • Activities of Daily Living • Efficacy, Safety, Side Effects and Cost (~$140/mo.)
Parkinson Syndromes • Idiopathic PD: • Up to 40% c dementia; 65% by age 85 • 3rd leading cause overall • Increases c age at dx., early hallucinosis & advanced motor signs, presence of depression
Pathological changes are those of Alzheimer’s dis. In addition to the typical pathology of Lewy bodies and neuronal loss in the substantia nigra. • Lewy bodies- intraneuronal, eosinophilic inclusions containing misfolded α-synuclein
2) Diffuse Lewy Body Disease • Motor sxs, dementia c often striking fluctuation and prominent haullucinosis • Lewy bodies are diffusely distributede in the cerebral cortex
Fronto-Temporal Lobar • Fronto-Temporal Dementia: Characterized by behavioral & executive function changes. 40-50% is familial. 10-20% of all dementias. Earlier age of onset. Atrophy of frontal & temporal poles. Pick bodies- argyrophilic round intraneuronal inclusions composed mainly of abnormal tau proteins. Unresponsive to AChI- tret c SSRIs & ? Memantine.
2) Primary Progressive Aphasia • Predominantly expressive • Other cognitive domains essentially intact • Focal atrophy seen on imaging • Eventual dementia
3) Semantic Aphasia • Predominantly a receptive aphasia • Atrophy seen more in parietal and posterior temporal regions
4) Other Tauopathies • Progressive Supranuclear Palsy (Steele-Richardson-Olsewski Syn.) • Corticobasal ganglionic degeneration
Vascular • 2nd leading cause of dementia • Subtypes: Cortical- large vessel & embolic stroke. Stepwise progression. More severe aphasia. Sensoro-motor abnormalities. • Subcortical- small vessel. Pseudobulbar palsy, gait impairment ( marche à petit pas), urinary incontinence
Treatment of Vascular Dementia • Attempt to limit progression: Hypertension, diabetes, homocysteine, lipids, cardiac • Cognitive: possibly AChIs & memantine • Behavioral: above + SSRIs
Typical Differential Points of Common Dementias at Initial Presentation MemoryLoss ImpairedLanguage VisuospatialImpairment Motor Signs Abnormal Behavior Vascular Event _ _ _ Alzheimer’sDisease FTD Dementia withLewy Bodies Ischemicvasculardementia NPH + + + + + ++ ± – ± – + – – ± – _ _ + + _ ++ + + ++ _ + _
Infectious • Cruetzfeldt-Jacob Disease • Familial • Sporadic • New Variant • Fatal familial insomnia • Gerstmann-Sträussler-Scheinker
Other Infectious • HIV • GPI • Lyme disease • Fungal • Tuberculous • PML
Metabolic • Thyroid • B 12 • Folate • Thiamine • Hepatic
Other • Huntington’s disease: irritability, apathy, impulsive behavior, poor personal hygeine, psychosis. Etiol. unclear until chorea appears esp. c spontaneous mutation. • HD gene on chrom. 4 contains trinucleotide repeats,CAG, encoding for glutamine preventing normal turnover of protein, huntingtin, in cytoplasm and nuclei. Abn. aggregation of this protein may→ pathology, cortical 7 subcortical
Other continued • Tumor • Subdural hematoma • Hydrocephalus • Demyelinating
Pseudodementia • Probably the most common etiology in the 30-60 patient population • Stress • Depressive disorders • Anxiety disorders
Clinical Evaluation • History • Neurological Exam • N-P testing • Blood work • Imaging & EEG
Counseling for Patients & Families Prognosis re. rate of decline & life expectancy Patient & family goals for treatment Review of finances & power of attorney Medical advance directives Driving Home safety Wandering (www.alz.org/Services/SafeReturn.asp) Long term care Resources for family and caregiver includ. Alz. Assoc. & ABA Commission on Legal problems for the Elderly