Neurodegenerative disorders Flashcards
What is Parkinson disease (PD)?
a progressive, neurodegenerative disease of the CNS (basal ganglia) characterized by a slowing down in the initiation and execution of movement (bradykinesia), increased muscle tone (rigidity), tremor at rest and impaired postural reflexes
What is the relationship between dopamine and acetylcholine?
dopamine is an inhibitory neurotransmitter that promotes movement– essential for normal functioning of the extrapyramidal motor system (posture, support and voluntary motion)
acetylcholine is an excitatory neurotransmitter that inhibits movement– responsible for nerve impulse transmission
What are lewy bodies?
a form of protein deposits that are present in the residual dopaminergic neurons that have been damaged
What causes akinesia and rigidity?
a relative excess of cholinergic activity– lots of acetylcholine in the body
Where are the dopamine-producing neurons?
in the substantia nigra of the midbrain– responsible for controlling voluntary movements
What are the diagnostic criteria for Parkinson Disease?
There is no diagnostic test for PD
-history and physical examination
-tremor, rigidity, bradykinesia, posture instability
-rule out use of meds that cause extrapyramidal side effects (EPS)
-MRI (to rule out other causes of symptoms)
Define Parkinsonism
-used to describe symptoms typical of Parkinson disease but can be drug-induced
-EPS of medications
What are the symptoms associated with autonomic dysfunction in PD?
-orthostatic hypotension can occur in up to 58% of pts with PD and can be aggravated or caused by antiparkinsonian agents
-common urinary symptoms with PD include frequency, urgency, and urge incontinence– most common is reduced bladder capacity because of involuntary detrusor muscle contractions at early stages of bladder filling
What is the acronym used to describe the clinical presentation of NMS?
FEVER
febrile
encephalopathy
vitals unstable
elevated muscle enzyme
rigid muscles
Caused by a lack of dopamine– a medical emergency
What happens if a pt with Parkinson disease’s levodopa dosing is too high?
-pt can experience hallucinations and psychosis
-need to differentiate from delirium
-looks a lot like schizophrenia
What is the difference in cognitive decline between PD and Alzheimer disease?
PD: loss of executive functions and visual spatial impairments are seen before memory loss
Alzheimer: memory loss is seen before loss of thinking and planning functions
Define executive functioning
a group of complex mental processes and cognitive abilities (such as working memory, impulse inhibition, and reasoning) that control the skills (such as organizing, remembering details, time management) required for goal-directed behaviour
What does a brain with Alzheimer disease look like?
-amyloid plaques
-neurofibrillary tangles
-atrophy and other structural changes
-decreased ACh levels
How is Alzheimer disease diagnosed?
rule out other causes for cognitive changes, cognitive testing such as MMSE and clinical history
What causes Alzheimer disease?
-failure to process and clear amyloid precursor protein results in the accumulation of toxic fragments of amyloid beta protein that leads to formation of diffuse neuritic plaques and death of neurons
-loss of neurons = brain atrophy with widening of sulci and shrinkage of gyri
-loss of synapses, acetylcholine, and other neurotransmitters contributes to the decline of memory and attention and the loss of other cognitive functions
