Dementia Flashcards
Risk factors
Advancing age in most forms of dementia Alzheimers disease:
• Genetic predispositions in both early and late onset, but genes alone are not sufficient to cause AD.
• Cardiovascular risk factors intensify severity of symptoms
• Down syndrome
• History or head trauma with loss of consciousness
• A range of other possible factors e.g. trace elements, viral connection Vascular dementia: Stroke and associated risk factors such as hypertension, diabetes, coronary artery disease, smoking
Causes/Subtypes
- Alzheimer’s disease: (Early onset before 65 and late onset). No known cause or biological marker.
- Vascular dementia: 90% associated with a history of one or more strokes, either large multi-infacts blocking large vessels or lacunar strokes affecting small arteries.
- Dementia with Lewy bodies: Unknown cause
- Dementias linked with other medical conditions eg Huntington’s disease, Parkinson’s disease
incidence/prevalence
- 5 to 8% of New Zealanders aged 65 and over, and 20% of people older than 80 years have dementia.
- A small proportion of people are diagnosed under age 65.
- Current dementia rates are likely to double by 2050. Prevalence of the most common subtypes –
- Alzheimers disease: 50-70% of all dementia
- Vascular dementia: 15-25% • Dementia with Lewy bodies: 10-20% of late onset dementia
Pathophy - Alzheimers disease (AD):
- Brain structure shrinks due to neuronal loss caused by formation of plaques and neurofibrillary tangles, and chemical changes occur.
- Plaques are made of amyloid proteins that normally break down and are washed away. In AD amyloid proteins partially break down producing sticky fragments that stick to each other and to other fragments of dying neurones forming into dense plaques.
- At the same time another protein (tau) which normally provides a track for transporting nutrients within neurons, becomes tangled and twisted. Together these two abnormal processes result in plaques, neuronal death and neurofibrillary tangles.
- These structural changes occur throughout the brain but are significant in the cortex and hippocampus.
- Low levels of the neurotransmitter acetylcholine (important for memory) are found in the hippocampus and amygdala.
pathophy - Vascular Dementia
- Loss of oxygen and nutrients due to stroke can lead to sudden onset of cognitive changes.
- Widespread atherosclerosis causing progressive blood vessel narrowing and ischaemic cell damage or repeated ‘mini strokes’ causing tiny blood vessel blockage and a little tissue death.
pathophy - Dementia with Lewy bodies
Dense tissue displaces normal tissue in nerve cells in cortical and subcortical regions causing cell death
pathophy - mixed dementia
Combination of Alzheimer’s disease and vascular dementia is very common
clinical presentation : Alzheimer -Early stage 2-3 years
Early signs mistaken for normal aging
Short term memory significantly impaired
Long term memory impairment begins
Difficulties with word finding and following complex conversation Starting to get lost in familiar places difficulty making decisions
Easily distracted Mood changes, social withdrawal, depression
clinical presentation - Alzheimer Middle stage 2-10 years
Early symptoms worsen
Decline in memory but less anxiety about this
Disorientated in place and time and wanders
Behavioural and psychological disturbances such as unusual anger, repeated questioning Increased personal and daily living dependence Hallucinations
clinical presentation - Alzheimer - late stage 8-12 years
Wide variance of symptoms
Becoming completely dependent and inactive
Increasing difficulty recognising close family or familiar objects Incontinence Muscle strength and voluntary movement reduced Increasing difficulty walking, eating, swallowing, communicating Sleep disturbances
clinical presentation - Vascular Dementia
Symptoms vary depending on lesion location and extent of damage Gradual cognitive decline as enough brain damage occurs to be noticeable as dementia
Very often a stepwise pattern of increasing symptoms associated with ‘mini-strokes’ which cause a sudden change such as memory impairment, then no new symptoms until another mini-stroke
Diagnosis - 3 diagnostic criteria
Memory impairment AND related changes in another cognitive domain such as language, abstract thinking, judgment or executive function
• Severe enough to affect social and occupational functioning
• Decline from previously higher level of functioning MRI detects early AD changes of neuronal loss
Medical menagement
Supportive care for patient and family/caregiver Treatment of depression that occurs in about 30% of people with dementia Alzheimer’s disease Cognition enhancing medications eg acetylcholine boosting medications Short term psychotropic medication for behavioural problems with caution due to adverse affects
Prognosis
Alzheimer’s disease: survival from diagnosis very variable. Death usually from complications Vascular dementia: Survival can be up to 20 years after recognition of dementia
Differential Diagnosis
Delerium, depression and medication side effects may cause dementia like symptoms. Delirium (acute confusion and disorientation) develops quickly, is frequently associated with an underlying medical condition and resolves when the condition clears. Mild cognitive impairment associated with memory changes may occur with normal aging.
