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extrapyramidal syndromes
CBN
24
Medical
Graduate
01/07/2011

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Term
what is the pyramidal system?
Definition
the lateralcorticospinal tract
Term
what is the extrapyramidal system?
Definition
the area of the central nervous system other than pyramidal cells of the cerebral cortex which exert control over movement - basal ganglia, cerebellum, and the smaller nucleii (subthalamic nucleus, substantia nigra, and locus cereleus). disease here = movement disorders.
Term
what is the striatum?
Definition
the caudate and putamen (internal NT is ACh)
Term
what are the putamen and the globus pallidus?
Definition
the lenticulate nucleus
Term
what is the interaction between the striatum and substantia nigra?
Definition
the substantia nigra sends dopamine to the striatum. the striatum sends GABA to the substantia nigra.
Term
what NT balance leads to hypokinesia?
Definition
less dopamine than ACh/GABA (tx w/anticholinergic)
Term
what NT balance leads to hyperkinesia?
Definition
more dopamine than ACh/GABA (give cholinergic or dopamine blocker)
Term
is the tremor in parkinsons functionally limiting?
Definition
not usually
Term
what is the most common tremor? tx?
Definition
postural tremor - familial (autosomal dominant). tx: propanolol (beta blocker), primidone (may be better for elderly pts), and small amounts of alcohol
Term
what is the most disabling tremor?
Definition
the cerebellar (intention) tremor, which increases in amplitude as the target is approached. the lesion is in the dentate nuclei. etiologies: MS, cerebellar degenerations, wilson's (wing beating tremor), cerebellar or brainstem strokes.
Term
what is chorea?
Definition
a state of *motor hyperactivity in which the speed amplitude and frequency of bodily movements are increased*. athetosis: slow forceful, writhing movement. ballismus: rapid, flinging movmement. etiologies: huntingtons, wilsons, neuroleptics, l-dopa. tx: decrease dopamine (haloperidol, reserpine)
Term
what characterizes huntington's disease?
Definition
facial dyskinesia, frequent blinking, "piano playing" fingers, dementia. tx: tetrabenzine. autosomal dominant.
Term
what is dystonia?
Definition
prolonged movements, often twisting - which distorts body parts. **often a sustained position at the end of a movement**. distribution can be focal (blepharospasm, oromandibular, torticollis, graphospasm), multifocal, or generalized. classification: primary (hereditary torision dystonia) or secondar (wilson's dx, neurleptics). tx: focal (botulinum), or high dose anticholinergics.
Term
what is a tic?
Definition
a rapid, sudden, unexpected movement (sound/vocal utterance) which can be suppressed for brief periods - but doing this is like trying not to "scratch an itch"
Term
what is tourette's syndrome?
Definition
multiple tics, which always involve part of the head. coprolalia, echolalia, pallilalia, echokinesis. tx: haloperidol (effective, but troublesome for younger pts), clonidine. onset in childhood. worsens w/stress.
Term
what is myoclonus?
Definition
sudden, shock-like movements of single groups of musculature. focal: due to local nerve irritation (hiccups, eyelids etc) or generalized: post-anoxic encephalopathy, uremia, jakob-creutzfeld disease (mad cow), hypocalcemia (think metabolic - pts w/uremic disease, kidney disease or hepatic failure: twitch-convulsion syndrome).
Term
what is the clinical presentation of parkinson's disease?
Definition
akinesia, rigidity, and tremor (also: postural instability, dementia, orthostatic hypotension (many drugs may aggravate this), and REM behavioral sleep disorder)
Term
what characterizes the akinesia seen in parkinson's?
Definition
mask-like facies (paucity of blinking), microphonia, micrographia, difficulty in initiating movement, shuffling gait (reduced arm swing), and festinating (involuntary accelerating w/shuffle + inability to decelerate)
Term
what characterizes the rigidity in parkinson's disease?
Definition
cogwheel-type, lead pipe when advanced (ratcheting feeling in wrist)
Term
what characterizes the tremor in parkinson's?
Definition
resting: disappears/decreases w/movement. embarassing, but not functionally limiting like akinesia/rigidity. may involve hands (pill rolling), mandible, or legs.
Term
what is the pathogenesis of parkinsons?
Definition
degeneration of substantia nigra, pars compacta – loss of dopaminergic neurons. MPTP, insecticides and genetics also can play part. cigarettes help protect against it.
Term
what is parkinson's tx?
Definition
*anti-cholinergics [cogentin/artane] for tremor particularly in young people (ADRs: dry mouth, difficulty with visual accommodation, blurred vision and can’t read, may get confused (elderly)), but won't help w/rigidity. *amantadine [symmetrel - antiviral]: increases dopamine synthesis, decreases re-uptake, post-synaptic stimulation. beneficial effects are short lived, often added to anti-ACh. *l-dopa+carbidopa [simemet 100/25]: carbidopa b/c it prevents peripheral decarboxylation of l-dopa to dopamine which gives a lot of side effects like nausea. COMT inhibitors may also be used to keep l-dopa from being broken down via the carboxy-methyl transferase pathway (extends sinemet duration another 4 hrs). l-dopa is **most effective w/rigidity and akinesia**. (ADRs:n/v, confusion, hallucinations, dose related dyskinesias, on-off phenomenon [last 2 - major long term problems]). *dopamine agonists: bromocriptine, pergolide, requip, mirapex, neupro - all of which postsynaptically stimulate the dopamine receptor - presently used to permit reduction of l-dopa dosage in certain situations (young pts, pts w/l-dopa-induced dyskinesias/on-off, initial use of dopamine agonists delays need for l-dopa and may lessen development of l-dopa induced side-effects. ADRs: hypotension, confusion, hallucinations. *MAO-B inhibitors: seligeline/rasagline which prevent breakdown of l-dopa, may prevent build-up of toxic metabolites, possibly neuroprotective, and mild dopamine agonist. *stem cell transplantation
Term
what are secondary causes of parkinson's?
Definition
antipsychotics (tx w/anticholinergics), metoclopramide, post-encephalitis, and manganese intoxication (welders)
Term
what is the association between REM sleep disorders and parkinson's?
Definition
if a bed partner acts out in the middle of night lashes out and screams, might have REM sleep behavioral disorder – there’s a 50% chance they will develop parkinson’s disease in 15 years. REM sleep behavior disorder is possibly earliest manifestations of a synucleinopathies of which parkinson's is the most common.
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