Chapter 19 (Neurocognitive Disorder)

Dementia

DefinitionDementia is an acquired, usually progressive generalized impairment of intellect, memory and personality with no alteration of consciousness.

Epidemiology1. Prevalence increases with age: 10% in patients

over 65 yrs of age; 25% in patients over 85 yrs of age.

2. Prevalence is increased in people with down syndrome and head trauma

3. Alzheimers dementia comprises >50% of cases; vascular causes comprise approximately 15% of cases

4. Average duration of illness from onset of symptoms to death is 8-10%

Subtypes1. With or without behavioural disturbance (e.g. wandering agitation)2. Early onset: age of onset <65 yrs3. Late onset: age of onset > 65 yrs

Diagnostic criteria for Dementia according to DSM-IVA. The development of multiple cognitive deficits

manifested by both 1. memory impairment ( impaired ability to

learn new information or to recall previously learned information)

2. ≥1 of the following cognitive disturbances:

# aphasia (language disturbance) # apraxia # agnosia # disturbance in executive functioning

B. The cognitive deficits in criteria A1 and A2 each cause significant impairment in social or occupational functioning and represent a significant decline from a previous level of functioningC. The course is characterized by gradual onset and continuing cognitive declineD. The cognitive deficits in criteria A1 and A2 are not due to any of the following: 1. other central nervous system conditions that cause progressive deficits in memory and cognition 2. systemic conditions that are known to cause dementia. 3. substance induced conditions.E. The deficits do not occur exclusively during the course of a deliriumF. The disturbance is not better accounted for by another Axis I disorder.

How a patient presents in dementia1. Loss of intellectual abilities disproportional to

age2. No disturbance of conciousness3. Increased forgetfulness4. Decreased concentration for tasks5. Difficulty with decision6. Problems with wordfinding7. Impaired ability to learn new information8. Irritability, emotional outbursts, labile mood9. Neglect of lifelong routines10.Decreased social and family interests11.Decreased recreational and occupational

interests12.Deterioration in day today routines especially

of learned skill13.Disturbance in sleep, nutritional intake and

caring for personal hygiene

Difference between Cortical Dementia and Subcortical Dementia

Characteristics Cortical Dementia Subcortical Dementia

I. Important Causes

Senile dementia, Presenile dementia (Alzheimer’s, Picks, Creutzfeldt disease) etc

Progressive Supranuclear Palsy; Huntington’s Chorea, Parkinson’s disease, Wilson’s disease

II. Personality Normal (unaware , lack of insight)

Depressed or apathetic

III. Motor System

a. Posture Normal Impaired (Stopped or twisted)

b. Gait Normal Impaired (ataxia)

c. Movement

Normal Impaired (Chorea, rigidity, tremors)

d. Activity Normal Impaired (Slow)

e. Speech Normal Impaired (Dysarthria, hypophonia)

IV. Mental State

a. Language Aphasia Normal

b. Memory Amnestic Forgetful

c. Visuospatial Skills

Impaired (Severe) Impaired (moderate)

d. Cognition Impaired (severe, amnesia, agnosia, apraxia, acalculia)

Impaired (slowed, forgetfulness, impaired, problem-solving strategy).

Investigations (rule out reversible causes)1. Standard2. As indicated: VDRL, HIV, SPECT, CT head in

dementia3. Indication for CT head: same as for delirium,

plus: age <60, rapid onset, dementia of relatively short duration (<2 yrs), recent significant head trauma, unexplained neurological symptoms (new onset of severe headache?seizures)

Possible etiologies of dementiaDegenerative dementia Alzheimers disease frontotemporal dementia perkinsons desease lewy body dementia idiopathic cerebral ferrocalcinosis progressive supranuclear palsyMiscellaneous huntingtons disease wilsons desease metachromatic leukodystrophy neuroacacthocytosisPsychiatri pseudodementia of depression cognitive decline in late life schizophrenia

Physiologic normal pressure hydrocephalusMetabolic Vitamin deficiencies (e.g. vitamin B12, folate) endocrinopathies (e.g. hypothyroidism) chronic metabolic disturbances (e.g. uremia)Tumor primary or metastatic ( meningioma or metastatic breast or lung cancer)Traumatic dementia pugilistica, posttraumatic dementia subdural hematomaInfection prion desease (e.g. creutzfeldt-jakob disease, bovine spongiform encephalities, gertsmann-straussler syndrome)

Acquired immune deficiency syndrome (AIDS) SyphilisCardiac,vasculur, and anoxia infarction (single or multiple or strategic lacunar) binswangers disease ( subcortical arteriosclerotic encephalopathy) hemodynamic insuffiency (hypoperfusion or hypoxia)Demyelinating disease Multiple sclerosis Drugs and toxins alcohol heavy metals irradiation pseudodementia due to medications carbon monooxide

Cortical and subcortical dementiafeatures Cortical

dementiaSubcortical dementia

1. Site of lesion

Cortex (frontal and tempo-parieto-occipital association areas, hippocampus

Subcortical grey matter (thalamus, basal ganglia, and rostral brain stem)

2. examples

Alzheimers , picks disease

Huntingtons choria, parkinsons, progressive supranuclear palsy, wilsons disease (not severe)

3. severity

severe Mild to moderate

4. Motor system

Usually normal

Dysarthria, flexed/extended posture, tremors, dystonia, chorea, ataxia, rigidity

5. Other features

Simple delusions; depression uncommon severe aphaxia, amnesia, agnosia, apraxia,acalculia; slowed cognitive speed (bradyphrenia)

Complex delusions,; depression common; rarely mania

6. Memory deficit (short term)

Recall helped very little by cues

Recall partially helped by cues and recognition tasks

7. personality normal Depressed or apathetic

Managemant1. Treat underlying medical problems and prevent

others2. Provide orientation cues for patient3. Provide education and support for patient and

family (day progress, respite care, support groups, home care)

4. Consider long term care plan (nursing home) and power of attorney/living will

5. Inform ministry of transportation about patients inability to drive safely

6. Consider pharmacological therapy # cholinesterase inhibitors (e.g. donepezil)

for mild to severe disease

# NMDA receptor antagonist (e.g. memantine) for moderate to severe disease # low dose neuroleptics (haloperidol, risperidone) and antidepressants if behavioural or emotional symptoms prominent – start low and go slow # reasses pharmacological therapy every 3 months