Dementia

Dementia is a progressive impairment of cognitive functions occurring in clear

consciousness.

The major defect in dementia is Memory loss (antrograde or retrograde).

Other cognitive functions (Attention, Comprehension, Abstract thinking, Judgment, Mood and affect, Personality, Social behavior)

Diagnosis According to DSM-IV-TR criteria:

A. Development of multiple cognitive impairments:

1. Memory (antrograde & retrograde).2. One (or more) of the following:• Aphasia• Apraxia • Agnosia• Disturbance in executive functioning (planning –

sequencing - organizing – abstracting).

B. Both A1 & A2 cause significant impairment in social and occupational functioning.

C. The deficits don’t occur in the course of delirium.

Epidemiology Prevalence:

5% in population over 65 years. Up to 40% in population over 85 years.

50 % - 60 % of all demented have Alzheimer's disease.

Causes of Dementia Neurodegenerative Diseases

Alzheimer’s diseaseParkinson’s diseaseDiffuse Lewy body diseaseHuntington’s disease Pick’s disease

Vascular Disease

Demyelinating DiseaseMultiple sclerosis

InfectionsHuman immunodeficiency virusTertiary syphilis

Trauma Tumors Primary Psychiatric

Pseudodementia

MetabolicVitamin deficiencies Chronic metabolic disturbances

Physiologic Normal pressure hydrocephalusEpilepsy

Drugs & ToxinsAlcoholMedicationsCOIrradiation

The major dementia syndromes

• Alzheimer disease• Vascular dementia• Dementia with Lewy bodies• Parkinson disease with dementia• Frontotemporal dementia (pick’s

dementia)• Reversible dementias

Reversible DEMENTIAD = DrugsE = Emotions (pseudodementia)& Endocrine DiseaseM= Metabolic DisturbancesE = Eye & Ear ImpairmentsN = Nutritional Disorders, Normal pressure

hydrocephalusT = Tumors, Toxicity, Trauma to HeadI = InfectionsA = Alcohol

Pathophysiology• Dementia is a symptom of a variety of specific

structural brain diseases as well as several system degenerations. Alzheimer's disease presently is the commonest cause in the developed world, causing a cortical & subcortical degeneration of ascending

cholinergic neurons and large pyramidal cells in the cerebral cortex.

1. Alzheimer’s Disease Alois Alzheimer (1864 – 1915)

Progressive dementia when all known causes have been ruled out.

“ Diagnosed By exclusion “

2 types1. With early onset (before 65 years old)

2. With late onset ( after 65 years old)

Etiology• Genetic factor

• Decreased brain Ach Concentrations

• Decreased brain choline acetyltransferase enzyme

• Degeneration of cholinergic neurons in the nucleus basalis.

Neuropathology Brain atrophy due to extensive neuronal loss

seen by Brain Imaging.

Two principal changes: (histopathologicly)1. senile or neuritic plaques (chemical deposits

consisting of degenerating nerve cells combined with a form of protein called ß-Amyloidß-Amyloid)

2. neurofibrillary tangles (malformations within nerve cells).

PET scan

Diagnosis Criteria mentioned before +D. Gradual onset and progressive course.E. Exclusion of systemic diseases causing

dementia.F. The disturbance is not better accounted for by

another Axis I disorder (e.g., major depression)

Definite diagnosis is postmortem (histopahologically)

2. Vascular Dementia Dementia due to cerebrovascular diseases

15 % - 30 % of all dementias.

Multiple cognitive impairments and behavioral changes + neurological signs & symptoms (gait

abnormaily – weakness of an extremity -Babinski's sign)

Risk factors (hypertension, heart diseases, Diabetes mellitus, hyperlipidemia)

Psychiatric co-morbidities Depression

Psychosis

Delirium

Anxiety

Work up Mini mental state examination

Full physical examination (neurological)

Full assessment for co-morbidities

Neuro-imaging (Brain CT, PET)

Lab investigations(Chemistry , CBC , LFTs ,KFTs , ESR , TSH , B12 and folate)

Treatment Treat medical problems

Provide orientation cues (clock , calendar)

Education and support for patient and family (day programs, support groups, home care)

Pharmacotherapy (doesn’t cure, but slow the disease process)

Pharmacotherapy1. Cholinesterase inhibitors in Alzheimer’s

disease Rivastigmine (Exelon) 3 – 6 mg 2x/day Tacrine (Cognex) 30 – 40 mg 4x/day Donepezil (Aricept) 5 – 10 mg /day

• SE: Nausea, vomiting, diarrhea and bradycardia in some people

2. N-Methyl-D-Aspartate (NMDA) Receptor Blocker

Memantine (Namenda®) is a unique medicine that works differently than cholinesterase inhibitors.

It may protect the brain from further damage. It is usually used along with a cholinesterase

inhibitor. Dizziness is the most common side effect, and aggression and hallucinations may worsen in

some people.

Treatment of behavioral symptoms

1. Depression • antidepressant medicine SSRIs, are usually

preferred (fluoxetine (Prozac® )

• Behavioral therapy involves changing the environment (e.g., encouraging exercise,

socializing with others)

2. AnxietyAnxiolytics (not benzodiazepine) as it interferes with

the formation and consolidation of memories of new material and may induce complete anterograde amnesia

3. Sleep Disturbance Trazodone 25 to 150 mg PO qhs

4.Agitation Antipsychotics (haloperidol)

Course & Prognosis Course

1. Progressive 2. Remitting3. Stable

Prognosis1. Irreversible (85 %)2. Reversible (15 %)