Flashcards in OHCM - Abnormal Involuntary Movements (Dyskinesia) Deck (62):
Abnormal involuntary movements (dyskinesia) - They may manifest with symptoms of:
3. Gait problems.
9. Tics and tremor.
Tremor - Note the ...?
3. Exacerbating factors (stress; fatigue).
Abolished on voluntary movement.
Rest tremor - Cause:
Irregular, large-amplitude, worse at the end of purposeful acts, eg finger-pointing or using a remote control.
Intention tremor - Cause:
Cerebellar damage (eg MS, stroke).
Absent at rest, present on maintained posture (arms outstretched) and may persist (but is not worse) on movement.
Postural tremor - Causes:
1. Benign essential tremor (AD, improves with alcohol).
Postural tremor developing after a delay of 10sec (eg in Parkinson's).
Re-emergent tremor - Treatment:
Surgery/Deep brain stimulation (DBS) helps some tremors.
Non-rhythmic, jerky, purpose-less movements flitting from one place to another - eg facial grimacing, raising the shoulders, flexing/extending the fingers.
Chorea - Causes:
The anatomical basis of chorea is uncertain but ...?
It may be the pharmacological MIRROR image of Parkinson's disease (L-dopa worsens chorea).
Large-amplitude, flinging hemichorea (affects proximal muscles) contralateral to a vascular lesion of the subthalamic nucleus (often elderly diabetics).
Recovers SPONTANEOUSLY over months.
Slow, sinuous, confluent, purposeless movements (esp. digits, hands, face, tongue), often difficult to distinguish from chorea.
Athetosis - Causes:
MC is cerebral palsy.
Most other "athetoid" patterns may now be better classified as ...?
Pseudoathetosis may be caused by ...?
SEVERE proprioceptive loss.
Brief, repeated, stereotyped movements which patients may suppress for a while.
Tics are common in ...?
Children - Usually resolve.
Motor + Vocal tics occur.
Tourette's syndrome - Treatment:
Consider psychological support, clonazepam, or clonidine if tics are severe.
--> Haloperidol may help but risks tardive dyskinesia.
Sudden involuntary focal or general jerks arising from:
Myoclonus is seen in ...?
1. Metabolic problems (below).
2. Neurodegenerative disease (eg lysosomal storage enzyme defects).
4. Myoclonic epilepsies (infantile spasms).
Benign essential myoclonus:
Childhood onset with frequent generalized myoclonus, without progression.
--> Often AD.
Benign essential myoclonus - It may respond:
Asterixis ("metabolic flap"):
Jerking (1-2 jerks/sec) of outstretched hands, worse with wrists extended, from loss of extensor tone - ie incoordination between flexors and extensors (="negative myoclonus").
Asterixis - Causes:
1. Liver or kidney failure.
2. Decr. Na.
3. Incr. CO2.
5. Thalamic stroke (consider if unilateral).
Tardive syndromes - Tardive means ...?
"Delayed onset", in this case after chronic exposure to dopamine ANTAGONISTS (eg antipsychotics, antiemetics).
--> Tardive syndromes are a source of much distress and disability, and may be permanent despite discontinuing all drugs.
Tardive syndromes - Classification:
1. Tardive dyskinesia.
2. Tardive dystonia.
3. Tardive akathisia.
4. Tardive myoclonus.
5. Tardive tourettism.
6. Tardive tremor.
Orobuccolingual, truncal, or choreiform movements, eg vacuous chewing and grimacing movements.
Sustained, stereotyped muscle spasms of a twisting or turning character, eg retrocollis and back aching/optisthotonic posturing.
Unpleasant inner sense of restlessness or unease +/- repetitive, purposeless movements (stereotypies, eg pacing).
Tardive tremor may respond to ...?
Treating tardive dyskinesia:
Get help. Gradually withdraw neuroleptics and wait 3-6months.
If still a problem, consider tetrabenazine 12.5-50mg/8h PO.
Examples of antipsychotics that are less likely to cause tardive syndromes:
Paracelsus used the term chorea to describe ...?
The jerking movements of medieval pilgrims travelling to the healing shrine of St Vitus - Reflecting the ancient Greek round dance accompanied by singing (hence chorus; choreography).
Paracelcus recognized 3 types of chorea:
1. Chorea arising from imagination (chorea imaginativa).
2. From sexual desire (chorea lasciva).
3. From corporeal causes (chorea naturalis).
Dystonia describes ...?
Prolonged muscle contractions causing abnormal posture or repetitive movements.
Dystonia - Patient's view:
I cannot, for example, draw the instrument [pen, pencil] toward me in a circular motion, eg the left arc of a circle, or the letter O. If I force the move, the movements become jerky and I lose all smoothness in the character. The same thing will happen when eating and trying to use a fork... I end up moving my mouth to the fork... instead of moving my hand to my mouth - awkward.
Dystonia - Classification - By age of onset:
1. Childhood (20yr).
Dystonia - Classification - Also by ...?
1. Part of the body affected.
2. By cause (there are many).
Idiopathic generalized dystonia:
Onset in childhood and often starts with dystonia in one leg, spreading to THAT side of the body over 5-10yrs.
Idiopathic generalized dystonia - Inheritance:
AD is common - Genetics show a deletion in DYT1.
Idiopathic generalized dystonia - Treatment:
Challenging. First exclude:
2. Dopa-responsive dystonia (often better after sleep, needs an L-dopa trial).
3. High-dose trihexyphenidyl (=benzhexol, an anticholinergic).
4. DBS may help.
Confined to one part of the body:
1. Spasmodic torticollis (head pulled to one side).
2. Blepharospasm (involuntary contraction of orbicularis oculi).
3. Writer's cramp.
Focal dystonias in adults are typically ...?
Idiopathic and rarely generalize.
Focal dystonias in adults are worsened by ...?
Focal dystonias - Treatment:
Injection of BOTOX into the overactive muscles is usually effective, but there may be side effects.
Writer's cramp (scrivener's palsy, graphospasm):
When trying to write, the pen is driven into the paper and flow of movement is poor.
Writer's cramp - Patient's view:
"I would look at [my fingers] and tell them to do one thing, and they'd do jagged things instead, I'd have full muscle control for everything, except putting a pen to a piece of paper.
Writer's cramp - Look for ...?
1. Hand and forearm spasm.
2. Dystonic arm posture.
3. Focal tremor.
5. Dominant-hand muscle hypertrophy.
Writer's cramp - Associated with?
Writer's cramp - EMG:
May correlate with physiological events:
1. Decr. reciprocal inhibition of wrist flexor motor neurons at rest.
2. Co-contraction of antagonist muscles of the forearm during voluntary activity.
Writer's cramp - EEG:
Abnormal motor command (sensorimotor region beta-rhythm).
Writer's cramp - Rx:
1. Beta-blockers + valproate often fail.
2. Breath-holding or arm-cooling may work.
3. BOTOX and EMG biofeedback may work.
Acute dystonia - May occur:
On starting many drugs, including:
2. Some antiemetics (eg metoclopramide, cyclizine).
Acute dystonia - Torticollis:
Head pulled back.
Acute dystonia - Trismus:
Acute dystonia - Oculogyric crisis:
Eyes drawn up.
Acute dystonia may be mistaken for ...?
Tetanus or meningitis, but such reactions rapidly disappear after a dose of an anticholinergic.