Basal Nuclei: Parkinsons And Huntingtons Flashcards
Absence of movement
Akinesia
Decreased amount of movements
Hypokinesia
Slowed movements
Bradykinesia
What terms are not used for corticospinal, corticobulbar, LMN, or muscular disorders
Akinesia
Hypokinesia
Bradykinesia
What are bradykinetic movements caused by
Increases inhibitory basal ganglia outflow to the thalamus
What do basal nuclei dysfunctions affect
Body movements, eye movements, cognition, and emotional regulation
What disorder is bradykinesia, hypokinesia, and akinesia seen with
Parkinson’s
If you have too much dopamine
Psychological disorders
If you have too little dopamine
Parkinson’s
Decreases spontaneous movements, without coma, can be seen in
Diffuse lesions of the frontal lobes, subcortical white matter, thalami, or brainstem reticular formation
Depression and advances schizophrenia
Can also causes marked psychomotor retardation, which in the extreme is called Catatonia
-mimics basal nuclei disorders
If you give someone too many anti-psychotics, what is the effect
Parkinson’s like symptoms
Types of rigidity
Spasticity
Cogwheel
What kind of rigidity is seen in corticospinal disoriders
Spasticity
Spastic rigidity
Spasticity
- strokes
- results from UMN damage
- tone initially increases and then decreases (clasp-knife) rigidity in corticospinal disorders
Cogwheel rigidity
- Parkinson’s
- caused by basal ganglia disorders
- continuous throughout attempts to bend the limb
- rigidity with a superimposed tremor
What kind of rigidity is seen in Parkinson’s
Cogwheel
__________ is a common idiopathic neurodegenerative condition caused by loss of dopaminergic neuron in the substantia nigra pars compacta
Parkinson’s
What is Parkinson’s caused by
Loss of dopaminergic neurons in the substantia nigra pars compacta
What is Parkinson’s characterized by
- bradykinesia
- rigidity
- instability
- tremor (at rest)
BRIT
Why is there a tenor at rest with Parkinson’s
Basal nuclei are what allow you to sit still without random movements, this is disrupted
Age of onset for Parkinson’s
40-70
How many people affected with Parkinson’s
1% of individuals over 65
Familial tendency and Parkinson’s
There is verbally no familial tendency, except in rare cases of familial Parkinson’s
Pathological cause of Parkinson’s
There is a loss of pigmented dopaminergic neurons in the substantia nigra pars compacta, causing the substantia nigra to appear pale to the eye on cross section
Are Lewy bodies pathognomonic for Parkinson’s
No
What is diagnosis of Parkinson’s disease is based on what
Almost ONLY on clinical features
Common manifestations of bradykinesia and hypokinesia in Parkinson’s disease
- micorgraphia
- masked fancies or hypomimia
- posture is stooped
- postural instability
- festinating gait
- armswing is dimnishied
What is often the 1st symptom of Parkinson’s
Micrographia, writing becomes small
Characteristic decrease in spontaneous blink rate and in facial expression
Marked facies or hypomimia
Festinating gait in Parkinson’s
Once they have started, they tend to walk with small shuffling steps
Late symptoms of Parkinson’s
- depression and anxiety
- Dementia
- diffuse Lewy bodies diseas
- bradyphrenia (slow response to Qs)
- seborrhea (oily skin) and hypersalivation
- impaired smell is an earlier symptom
When should a diagnosis other than idiopathic Parkinson’s should be suspected
- patient does not respond to levodopa
- symmetrical symptoms
- absence of resting tremor
- rapid progression of symptoms
Shy-Crager syndrome
Parkinson’s + orthostatic hypotension
Parkinson’s like diseases
Dementia with Lewy bodies
Main mode of treatment for Parkinson’s
Levodopa
A progressive, untreatable disorder which patients lose their ability to function and experience increasing dementia
Huntington’s disease
The initial symptoms indicative of this disease generally being to appear ______ years of age
45-44
What kind of disease Huntington’s
Genetic disorders inherited in autosomal dominant fashion
What is the Huntington disease due to
Mutation on the short arm of chromosome 4
Huntington’s disease at the molecular level
Mutated gene has multiple copies of the DNA sequence CAG, which codes for glutamate
What do the CAG repeated in huntingtons result in
Addition of glutamate residues inside the gen coding for the protein. Huntington
Dysfunction Huntington does what
Leads to premature death of neurons in the striatum
When is Huntington’s more severe
Patients with larger numbers of repeats have a more severe illness with an earlier onset
Trinucleotide repeat disorders
- DNA replication error
- abnormal amplification of sequence of 3 nucleotides. This may prevent normal expression of the gene or encode a dysfunctional protein
- will worsen with each generation
- most repeats contain guanine and or cytosine
What is the trinucleotide repeat in huntingtons disease
CAG
What is the primary responsibility for huntingtons
Glutamate exitotoxicity especially at caudate nucleus
What happens when glutamate binds its receptor
Opens calcium channels
Glutamate binding receptors in huntingtons
An unknown mechanism causes glutamate to persist at the NMDA receptor, which opens calcium ion channels, the resulting influx of Ca causes an increase in intracellular calcium, which triggers a cascade that leads to cell death
Signs and symptoms of huntingtons
Initial symptoms are susally subtle chorea and behavioral disturbances
-subtly eye abenormalities such as slow saccades, impaired smooth pursuit, sluggish nystagmus
Early movement abnormalities of huntingtons
Clumsiness and subtle chorea, such as mild jerking, fidgety movements
Psychiatric manifestations of huntingtons
- affective disorders such as depression and anxiety
- OCD
- impulsive or destructive behavior
- psychosis
Cognitive impairments with huntingtons
- decreases attention
- memory disorder that affects both recent and remote memories
- atomic aphasia
- impaired executive functions
Advanced huntingtons
Patients are profoundly demented and lose the ability to make nearly all purposeful movement, they are bedbound, cannot speak, and usually die of respiratory infection
Median survival from onset of huntingtons
15 years
Huntington’s and MRI
Flattening of the head of the caudate nucleus
MRI of huntingtons more advanced
Milder atrophy of the cerebral cortex also occurs
