Dementia Part 1 Flashcards
DSM-5 Clinical Definition of Dementia
CCELL
- Evidence of significant cognitive decline, from prior level of performance in one or more cognitive domains (complex attention, executive function, learning and memory, language, perceptual-motor or social cognition)
- Concern of the individual/informant/clinician that there has been significant decline in cognitive function
- Substantial impairment in cognitive performance preferably documented by standardized neuropsychological testing or in its absence other quantified clinical assessment
- Cognitive deficit interferes with independence in everyday activities (IADLs, ADLs)
- Cognitive deficits do not occur exclusively in the context of delirium
- Cognitive deficits are not better explained by another mental disorder
DSM-5 Clinical Definition of Minor Neurocognitive Disorder (MCI)
- Evidence of modest cognitive decline, from prior level of performance in one or more cognitive domains (complex attention, executive function, learning and memory, language, perceptual-motor or social cognition)
- Concern of the individual/informant/clinician that there has been mild decline in cognitive function
- Modest impairment in cognitive performance preferably documented by standardized neuropsychological testing or in its absence other quantified clinical assessment
- Cognitive deficit interferes with independence in everyday activities (IADLs, ADLs)
- Cognitive deficits do not occur exclusively in the context of delirium
- Cognitive deficits are not better explained by another mental disorder
What is Minor Neurocognitive Disorder (MCI)?
People with MCI can live for decades without developing dementia
How to differentiate diagnosis of delirium?
Diagnosis of delirium by Confusion Assessment Method (CAM)
Presence of features 1, 2 and either 3 or 4
- Acute onset and fluctuating course
- compare mental status with baseline
- symptoms of delirium come and go
- Inattention
- Disorganized thinking
- disorganized, rambling, illogical flow of ideas
- Altered level of consciousness
- as long as not alert; may be hyperalert/vigilant, lethargic/drowsy, stupor, coma
Factors that contribute to /may present with delirium
Drugs - e.g., antihistamines
Electrolyte and endocrine imbalance - e.g., dehydration, hyponatremia, hypothyroidism; blood works required
Lack of drugs - e.g., BZD withdrawal, increased pain levels
Infections - physical exam, diagnostic tests
Reduced sensory input - e.g., lack of hearing and vision aid
Intracranial disorders - e.g., stroke, bleed
Urinary and fecal disorders - e.g., urinary retention, constipation
Myocardial and pulmonary disorders - e.g., MI, arrhythmias, hypoxia, hypercapnia
(similar to factors contributing to BPSD)
Hallmark presentations of dementia
CPBSP
Canberra plaza behind sunshine plaza
- Cognitive (most prevalent symptoms)
- Early stage: short-term memory loss, anosmia, semantic deficits
- Late stage: long-term memory loss, more marked expressive difficulties and loss of language
- Psychological
- Early stage: apathy, depressive symptoms
- Late stage: delusions, lack of insights
- Behavioural
- Early stage: withdrawal from social engagement, disinhibition
- Late stage: aggression, hallucinations, wandering
- Sleep
- Early stage: rapid eye movement behavior disorder - a/w dreaming, memory consolidation (dream-enactment)
- Late stage: altered sleep-wake cycle
- Physical
- Early stage: gait impairment, falls
- Late stage: repetitive purposeless movements, parkinsonism, seizures
Types of Dementia
- Alzheimer’s disease (progressive neurodegenerative disease)
- Vascular dementia (contributed by vascular events such as stroke, that precedes dementia)
- Lewy body dementia
- Frontotemporal dementia
- Mixed type (commonly AD + VD)
Alzheimer’s disease onset and course
- Slow onset and gradual progressive over months or years
Alzheimer’s disease history, examination, and cognitive features in early stage
History:
- Presenting symptom is typically short-term memory loss
Examination/Cognitive testing:
- Episodic memory impairment accompanied by other subtle cognitive deficits, such as visuospatial problems and anomia
Alzheimer’s disease pathologic characteristics
Brain atrophy
- Esp of the mesial temporal lobe (hippocampus, involved in learning and memory), may also involve neocortex involved in cognition
- Atrophy is due to degeneration of cholinergic neurons
Histologic hallmarks
- Senile plaques (if pt has AD, high chance to see senile plaques)
- Neurofibrillary tangles (not characteristics of AD, may find in other neurodegenerative diseases as well)
How to observe senile plaques and neurofibrillary tangles?
Can only be seen in brain biopsy with is invasive, not routinely done
However, levels of amyloid and tau protein in CSF can be measured via lumbar puncture (not routinely done)
What are senile plaques?
Neuritic plaques containing aggregates of B-amyloid peptides, to form B-amyloid plaques (OUTSIDE CELL)
Derived from cleavage of larger amyloid precursor protein (APP) via action of B-secretases into insoluble peptides that create a monomer called B-amyloid
What happens?
- In normal circumstances, APP helps with neuron growth and repair
- Overtime, gets broken down by enzymes (B-secretases into insoluble peptides, a- secretases into soluble peptide that is excreted)
- B-amyloid are sticky and aggregate to form a plaque
- Plaque can potentially get between the neurons, which can interfere with neuron-to-neuron signaling, causing neurotoxicity and affecting neurofunction
What else?
- B-amyloids also start up immune response and cause inflammation which may disrupt surrounding neurons
- B-amyloids also deposit around blood vessels in the brain, may lead to amyloid angiopathy, weakened the walls of blood vessels, increase risk of hemorrhage and rupture
What are neurofibrillary tangles?
Hyperphosphorylated tau protein aggregates forming paired helical filaments (PHF) (INSIDE CELL IN CYTOPLASM/AXONS/DENDRITES)
- Tau: tubulin associated protein needed for microtubule (cytoskeleton) stabilization and intracellular transport
What happens?
- Activation of kinase, an enzyme that transfers phosphate groups to the tau protein
- tau protein changes shape and stops supporting microtubules, tau proteins clumps up/gets tangled leading to neurofibrillary tangles + loss of skeletal microtubules
- Neurons with tangles and non-functioning microtubules cannot send signals, may undergo apoptosis
Non-modifiable risk factors for AD
- Age (affects 5-10% of people >65y; 50% of people >85y)
- Female
- Ethnicity (black, hispanic)
- Genetics (APOE4 gene - regulator of lipid metabolism, affinity for B-amyloid protein)
Is routine testing for APOE4 gene done? Why or why not?
No, but may be done in cases where there is clear family history of genetic predisposition
*One allele => 50% incr risk
*Two alleles => substantial incr in risk
Modifiable risk factors for AD
- Hypertension
- Diabetes
- Binge drinking
- Smoking
- Limited physical activities
- Obesity
- Hearing loss
- Depression
Stages of AD
- Cognitive screening tools
- Mini mental state examination (MMSE) - out of 30
- Mild: 20-24
- Mod: 10-19
- Severe: <10
- Montreal cognitive assessment (MOCA)
- Mild: 18-25
- Mod: 10-17
- Severe: <10
Clinical Evaluation of Suspected Dementia
- Medical history (focusing on cognition and function)
- Cognitive examination
- Neuropsychological testing (if needed)
- Etiology of dementia determined based on:
- Medical history (neurologic/general medical/family)
- Physical examination (neurological signs - cognitive impairment, focal signs, parkinsonism; pertinent systemic signs - vascular and metabolic diseases)
- Neuropsychological testing
- Laboratory testing (thyroid function, vit b12 levels, metabolic/infectious/autoimmune etc.)
- Structural brain imaging with CT or MRI (neuroimaging is adjunct, more to exclude other brain pathologies)
- CSF and blood biomarkers of AB and pTAU not routine
Describe what will appear on structural brain imaging with CT or MRI for the diff types of dementia
AD: generalized or focal cortical atrophy, often asymmetrical, hippocampal atrophy (in mesial temporal lobe)
Vascular: brain infarcts or white matter lesions
Frontotemporal dementia: frontal lobe or anterior temporal lobe atrophy
Other abnormalities such as brain mass (Tumor) and hydrocephalus