Movement Disorders: Hemibalismus And Athetosis Flashcards
This type of movement disorder is characterized by writhing, twisting movements
Athetosis
What are some important causes of athetosis
- medications: levodopa
- other- perinatal hypoxia, Huntingtons disease, antipsychotic meds
This type of movement disorder is characterized by continuous involuntary movements that have a fluid or jerky, constantly varying quality
Chorea
What do Mild cases of chorea commonly get mistaken for
Low amplitude chorea may be mistaken for fidgeting
Severe cases of chorea
Larger amplitude movements resemble frantic break dancing
Consists of uncontrolled flinging (ballistic) movements of an upper or lower extremity but is most characteristically seen in the upper extremity
Ballismus (hemiballismus)
Is basllismus usually unilateral or contralateral?
Unilateral
-seen as hemiballismus
Ballismus (hemiballismus) is most commonly seen in patients with vascular lesions localized to the ______________________
Contralteral subthalamic nucleus
What is hemiballismus caused by
Damage to the subthalamic nucleus or to the subthalamic projections to GPi (lenticular fasciculus) caused by stroke
Onset of hemiballismus following stroke
May be acute but more often delayed and insidious onset
What are some other focal pathologies other than stroke that can cause hemiballismus
- abscess (infection)
- demyelinating disease (MS)
- neoplasm (tumor)
Where is athetosis usually seen
Usually distally in limbs: affects wrist, hand, fingers more than rest of the arm
What is athetosis usually due to
Stroke (ischemic) and white matter (axonal) damage
What disease can athetosis be seen in
Huntingtons disease
-along with hemiballismus
What is it called when athetosis and hemiballismus are seen together in huntingtons disease
Choreoathetotic movement
What causes athetosis
- disruption of the direct pathway
- stroke involving the internal capsule
- NOT neurodegenerative disease
- due to partial damage to GPi projections to thalamus via the ansa lenticularis or lenticular fasciculus
- can occur due to a small lesion (infarct, demyelinating plaque, etc)
- can also emerge as a delayed, residual deficit after an internal capsule infarct, as with hemiballismus
What are the two kinds of strokes you will see involving the internal capsule
Mixed sensorimotor stroke
Pure motor stroke
Mixed sensorimotor stroke involving the internal capsule
Since both motor and sensory fibers are carried in the internal capsule, a stroke to the posterior limb of the internal capsule can lead to contralateral weakness and contralateral sensory loss
Pure motor stroke involving the internal capsule
- like a UMN lesion
- lacunar infarct, result of an infarct affecting the posterior limb of internal capsule
- weakness of face, arm, and/or leg
- caused by infarct in the internal capsule is the most common lacunar syndrome
- UMN signs: hyperreflexia, babinski, spasticity
What kind of infarct could give you a hemiplegic gait
Right internal capsule infarct
Hemiplegic gait following right internal capsule infarct
- stabilizes posture by favoring intact side
- pt swings body to passively shift leg forward
- flexed posture of affected arm
- lower face weakness
- head tilt
If a patient comes in with arm/leg weakness, how do you tell if it is internal capsule stroke or a cortical stroke
The presence of the following signs along with the weakness will be indicative of a cortical stroke
- gaze preference or deviation
- expressive or receptive aphasia
- VF deficits
- visual or spatial neglect
Blood supply to the striatum and globus pallidus
Lenticulostriate branches of the MCA
What are some other possibilities of blood supply to the globus pallidus other than the lenticulostriate branch of the MCA
Anterior choroidal artery
What are some other possibilities of blood supply to the caudate nucleus other than the lenticulostriate branch of the MCA
Recurrent artery or Heubner (branch of ACA)
Why is it hard to tell what arteries are affected in a stroke near the basal nuclei
There is a lot of variability in blood supply to the area
Blood supply to the internal capsule anterior limb
Lenticulostriate branches of MCA
-less often branches of ACA
Blood supply to genu of the internal capsule
Lenticulostriate branches of MCA
Blood supply to posterior limb of internal capsule
- lenticulostriate branches of MCA
- anterior choroidal artery of ICA
What is the blood supply to the subthalamic nucleus
Anterior choroidal artery
What structures does the anterior choroidal artery supply
- subthalamic nucleus
- small inferior portion of the globus pallidus
- inferior portion of the internal capsule
What do the more superior aspects of the internal capsule receive blood supply from
Lateral striate artery branches
Blood supply to basal nuclei
Medial and lateral striate arteries
Vascular territories for caudate nucleus, putamen, globus pallidus
No clearly defined vascular territory
- significant overlap or anastomoses among branches of the medial and lateral traits arteries
- occlusion in any given branch leads to variable infarcts within the basal nuclei
Hemorrhage and basal nuclei
Hemorrhages can involve all of the basal nuclei and if unchecked, can becomes fatal
What disease is associated with low dopamine levels
Parkinson’s
What is associated with too much dopamine levels
Psychiatric problems such as schizo
System from the ventral tegmental area to prefrontal cortex, limbic regions, and ventral striatum
Mesocorticolimbic system
System from substantia nigra to caudate nucleus and putamen
Nigrostriatal
What happens when there are problems in the mesocorticolimbic system
- psychiatric problems (schizo)
- explains depression during Parkinson’s too
What is a major target of the mesocorticolimbic dopamine pathway from the ventral tegmental area
Nucleus accumbens
What underlies behavioral side effects L-Dopa treatment: impulsive/risky behavior, manic/psychotic episodes
Excessive activation of the mesocorticolimbic system
Diverse functions of the caudate nucleus
Not only projects to motor nuclei of the thalamus, but also to centromedian (part of the reticular activating center) and medodorsal nuclei (connects with prefrontal cortex), which are involved in promoting optimal alertness and executive functions of the prefrontal cortex (cognition, behavioral regulation)
In huntingtons disease, degeneration in ___________likely contributes to emotional disturbances: volatile emotions
Caudate nucleus
A basal nuclear disorder that is iatrogenic in nature, that is , caused by medical intervention for treatment for another disease. It is caused by chronic treatment with neuroleptic meds
Tardive dyskinesia
What is the manifestation of tardive dyskinesia
Uncontrolled involuntary movements, particularly of the face, mouth, and tongue, and cogwheel rigidity, may be temporary or permanent
What is the action of neuroleptic drugs
Block dopaminergic transmission throughout the brain. The primary target cells are those in the ventral tegmental area that form the mesolimbic dopaminergic pathway.
Prolonged treatment with neuroleptic drugs
May lead to blockage of the D2 dopamine receptors, which causes imbalance in the nigrostriatal influence on the basal nuclear motor loop and ultimately results in overestimate disorders
Why is treatment for tardive dyskinesia compacted
By the fact that withdrawal of the causative medication may result in exacerbation of the underlying psychotic state.
