Week 3- dementia Flashcards
What is dementia?
An acquired and persistent generalised disturbance of higher mental functions in an otherwise fully alert person.
What is the difference between primary and secondary dementias?
Secondary dementias are other disorders giving rise to dementia. Whereas primary is just the dementia alone.
Give examples of primary dementias?
Alzheimer’s disease, Lewy body dementia, Picks disease, Huntington’s disease.
Describe Alzheimer’s disease?
Progressive impairment of higher intellectual function. Associated with mood and behaviour changes. As it progresses- progressive disorientation, memory loss and aphasia indicating severe cortical dysfunction.
Macroscopically- what changes would you see in the brain in a patient with Alzheimer’s disease?
Atrophy of the cortex- typically affecting frontal and parietal lobes.
Reduction in weight
Narrowing of gyri and widening of the sulci.
Compensating dilatation of the ventricles.
Brainstem and cerebellum are normal.
Microscopically- what changes would you see in a brain of a patient with Alzheimer’s disease?
Neuronal loss with associated astrocyte proliferation. Gliosis.
Neurofibrillary tangles (intracytoplasmic accumulations of microtubules and proteins called Tau)
Neuritic plaques- formed by A beta amyloid plaques. Surrounding astrocytes and microglia.
What is the importance of amyloid AB in Alzheimers disease?
It forms the central element of the neuritic plaques. Also found in patients with trisomy 21 (downs syndrome)- meaning they have early onset Alzheimer’s.
Genes associated with Alzheimers and inheritance
Implicated genes are the amyloid precursor protein (APP) and presenillin 1 and 2.
May have a familial connection.
Who is affected by Alzheimers disease?
Its a disease of the elderly (over the age of 65).
Brief pathogenesis of Alzheimer’s?
Depositation of Alpha- beta amyloid is the initial event. These form neuritic plaques which activate inflammatory cells.
Real disruption is caused by a-beta oligomers that get into the synaptic cleft.
What is amyloid angiopathy?
A beta peptide accumulates in vessel walls- can disrupt the blood brain barrier. Stains Congo red.
Describe Lewy body dementia?
This is the third most common form of dementia. It is a progressive dementia with hallucinations and fluctuating levels of attention/cognition.
How does Lewy body dementia differ from Alzheimers disease?
Lewy body dementia fluctuates in severity on a day to day basis.
What features present early in Lewy body dementia?
Parkinson features present at onset or shortly after.
Describe features of Parkinson’s?
Loss of facial expression, pill rolling resting tremor, rigidity, slow and difficult initiation of movement.
Describe the pathology of Lewy body dementia?
Degeneration of the substantia nigra as seen in Parkinson’s.
Accumulation of lewy bodies in vulnerable sites.
Macroscopically- what will the substantial nigra look like in Lewy body dementia?
Loss of pigment- pale.
Microscopically- what does Lewy body dementia present as?
Loss of pigmented neurones
Reactive gloisis
Remaining neurones show Lewy bodies. Lewy bodies are eosinophilic, round, elongated bodies with a dense core and surrounding pale halo.
What is Huntington’s disease and what is the classic triad?
A neuropsychiatric disorder that presents in the younger population.
Triad of emotional, cognitive and motor disturbances.
Symptoms of Huntington’s disease?
Chorea (dance like movements) Myoclonus (spasmodic jerky contractions of a group of muscles) Clumsiness Slurred speech Depression Irritability Dementia develops later.
How is Huntington’s disease inherited?
Autosomal dominantly
Describe the macroscopic appearance of a sufferer of Huntington’s disease’s brain?
Atrophy of the basal ganglia- especially the caudate nucleus.
What is Pick’s disease also known as?
Fronto-temporal dementia
Describe Picks disease
Progressive dementia affecting a slightly younger age group than Alzheimers disease and Lewy body dementia. Characterised by progressive changes in character and social deterioration leading to impairment of intellect, memory and language.
