movement disorders Flashcards
benign essential tremor?
cause is unknown, often inherited in autosomal dominant manner (familial)
-causes minimal disability
when can the B. Essential tremor begin?
at any age
what can make the tremor worse?
emotional stress
what can relieve a benign essential tremor?
small quantities of alcohol
what are the Clinical features of BET?
rhythmic, 6-8 hz, to and fro motion, usually of the upper extremities, but sometimes of the head
-speech can also be affected if it involves the laryngeal muscles
what is titubation?
the act of staggering or reeling; a staggering gait with shaking of the trunk and head, commonly seen in cerebellar disease.
tx fo BET?
low doses of BB, usually propanolol]
-primidone if BB fails
what is primidone?
MOA: barbituate, acts on GABA receptors, increasing synaptic inhibtion (metabolized to phenobarbital)
ADR: ataxia, vertigo, N/V, diplopia
Parkinson’s disease?
-second most common neurodegenrative disorder
idiopathic parkinson? epidemiology
occurs in all ethnic groups, equal sex distribution, and most often begins btw 45-65 years old +/- familial component
what is the Pathophys of PD?
degenration of cells in the substantia nigra= deficiency of the neruotransmitter DA and an imbalance of DA and acetylcholine
Surviving substantia nigra neurons often contain Lewy bodies, which are intracytoplasmic proteinaceous inclusions (comprised of alpha-synuclein)
what are some complaints that PD pts may have?
slowed movements, difficult arising from a sited position, climbing up and down stairs, trouble getting dressed and difficulty w/ handwriting *micropahgia
What are the essential featrus that est a dx of PD?
resting tremor, bradykinesia, rigidity (check the muscle tone), and postural instability (shufflig gat)
what is normally the presenting complaint or PD?
-tremor that is most noticeable at rest, at 4- cycles per sec, and may be only very slifht with voluntary effort
“pill rolling”
how does the tremor of PD progress?
initially confied to one limb or the limbs on one side, but eventually, it may be present in all the limbs and the lips and mouth. bypasses the head
what may bradykinesia look like in a PD pt?
generalized slowness of voluntary movements evident in the slow shuffling gait, reduced arm swing, slowed rapid alternating movements, infrequent blinking and mask like features
what does rigidity look like in a PD pts?
found on passive ROM testing- think cogwheel rigidity
what does postural instability look like in a PD pt?
difficulty in standing from a seated position, unsteadiness on turning, difficulty in stopping, and a tendency to fall
what cognitive disorder/ sx can be seen in PD pts?
depression, dementia, cognitive impairment,
diagnostic testing for PD?
none, blood tests and imaging studies can be done to r/o other causes
what is the tx of PD?
balance acetylcholine w/ anticholinergic drugs and levodopa (precursor of dopamine)
what can work in pts w/ advanced PD w/ dyskinesias?
amantadine
what is the first line tx of parkinsons
levodopa-crosses bBBB and is converted to dopamine in body. can be used w/ carbidopa, that allows lower doses of levodopa and reduced side effects
what does carbidopa do?
Inhibits dopa decarboxylase (DDC)
Prevents peripheral conversion of levodopa to dopamine
Allows more levodopa to cross BBB
Increases bioavailability
what do you need to monitor in pts on levodopa?
LFTs
what are adverse effects of levodopa?
Dyskinesias
On-off” Effect – fluctuations in clinical response to levodopa
End of dose wearing off
“Off” = marked akinesia
“On” = improved mobility but marked dyskinesia
Thought to be related to fluctuations in levodopa plasma concentrations
Fluctuations can be “smoothed out” by incorporating a dopamine receptor agonist into pharmacotherapy
Also: N, anorexia, hypotension, confusion, insomnia, nightmares, schizophrenic-like syndrome
when are dopamine agonists used in PD?
for pts that have become refractory to levodopa and carbidopa
(bromocriptine, cabergoline)
what other options that can be used for tx of PD?
Monoamine oxidase B inhbitors: selegiline
catecholamine-O-methytransferase inhibitors: tolcapone and entacopone
how do MAO-B work?
inhibits breakdown of dopamine
what are some ADR of dopamine agonists?
cardiac valvulopathy when used at PD dosing
how do COMT inhibitors work/
reduce the metabolism of levodopa to #-O methyldopa and result in more stable plasma levels and more constant dopminergic stimulation of the briain
what are non-drug tx for PD
PT, household modifications, special utensils
psychological support
what are some anticholinergic drugs that can be used for PD?
benztropine, trihexyphenidyl, amantadine
Huntington Disease
inherited, autosomal dominant disorder
-5/100,000
what is the gene responsible fo r HD?
on the short arm of chromosome 4
expansion of CAG trinucleotide
*number of repeats determines the age of onset
> 40, sx will appear
when do sx of HD develop?
after 30 yo
CF of HD?
progressive chorea and dementia
usually fatal w/in 15-20 years
what are the earliest mental changes of HD?
behavorial, with irritability, moodiness, and antisocial behavior that generally progresses to an obvious dementia
what are the earliest physcial signs of HD?
mere restlessness of fidgetiness, but eventually severe choreiform movements and dystonic posturing
what is chorea?
– rapid involuntary dance-like movements involving the face, trunk, and/or limbs
diagnositic studies of HD
CT will show cerebral atrophy, and atrophy of the caudate nucleus
MRI and PEET scans show decreased glucose metabolsim in an anatomically normal caudate nucleus
tx of HD
no cure, and progression can’t be halted
-symptomatic tx: phenothiazines to control dyskinesia and haloperidol or clazpine to control any behaviorl disturbances
what is a drug that can help control chorea?
tetrabenazine, but it can worsen cognitive problems
mechanism of action involves blocking the transport of dopamine into vesicles in the presynaptic terminal. This depletes dopamine from the vesicles and reduces dopamine transmission
