What are dyskinetic disorders charcterised by?
Characterised by impaired planning, control or execution of movement
What is a resting tremor?
Tremor which is abolished with on voluntary movement
What is the cause of a resting tremor?
What is an intention tremor?
Intention tremor is a slow (2–4 Hz) tremor during voluntary movement that develops as the limb approaches the target.
What tests would you do to assess for an intention tremor?
- Finger-to-nose test
- Heel-shin sign
Why does an intention tremor occur?
Delays in motor initiation and movement termination, and abnormalities of movement force and acceleration, contribute to intention tremor
What can cause an intention tremor?
- Intoxication – alcohol, benzodiazepine
- Cerebellar infarction
- Multiple sclerosis
- Vertebral artery dissection
- Cerebellar mass lesion – tumour, abscess, AVM
- HSV cerebellitis
- Hereditary cerebellar degeneration (Freidreich’s ataxia)
- Paraneoplastic cerebellar degeneration
Remember mnemonic mavis - MS, Alcohol, Vascular problems, Inherited ataxia/Infection, Space occupying lesions
What is a postural tremor?
A tremor which is absent at rest, but present on maintained posture (e.g. outstretched arms) and may persist on movement
What are causes of postural tremor?
- Benign essential tremor
What is chorea?
Non-rhythmic, jerky, purposeless movements flitting from one place to another e.g. facial grimacing, raising the shoulders, flexing/extending fingers
What can cause choreic movements?
- Systemic disease - thyrotoxicosis, SLE, antiphospholipid syndrome, primary polycythaemia
- Genetic diseaseb - Huntingtons disease, neuroacanthocytosis
- Drugs - levodopa, OCP
- Post infection - Syndenham's chorea
What is syndenham's chorea?
A rare atuoimmune complication of group A strep infection, characterized by rapid, uncoordinated jerking movements primarily affecting the face, hands and feet. It is caused by destruction of cells in the corpus striatum of the basal ganglia
What drug can worsen chorea symptoms?
What is hemiballismus?
Large-amplitude, flinging hemichorea (affecting proximal muscles) conttralateral to a vacular lesion of the subthalamic nucleus - often elderly diabetics
What is athetosis?
Slow, sinuous, confluent, puposeless movements (esp. digits, hands, face, tongue) which are often difficult to distinguish from chorea
What are causes of atheotosis?
Most common cerebral palsy
What is pseudoathetosis?
Athetosis caused by severe proprioceptive loss
What are tics?
Brief, repeated, sterotyped movements which patients may suppress for a while
What is myoclonus?
Sudden involuntary focal o general jerks arising from cord, brainstem or cerebral cortex
What are causes of myoclonus?
- Physiological myoclonus
- Myoclonic Epilepsy
- Variant CJD
- Metabolic disorders - hepatic/renal failure, dementia/neurodegenrative disorders
What is myoclonus caused by hepatic/renal failure called?
Asterixis (metabolic flap) - jerking (1-2 per sec) of outstretched hands, worse with wrists exteded, from loss of etensor tone (type of negative myoclonus caused by imbalance between flexors and extensors)
What can cause asterixis?
- Liver failure
- Kidney failure
- Thalamic stroke - if unilateral
What are tardive syndromes caused by?
Irreversible tardive symptoms caused by chronic exposure to dopamine antagonists
What are the different types of tardive syndromes?
- Tardive dyskinesia
- Tardive dystonia
- Tardive akasthesia
- Tardive myoclonus
- Tardive tremor
- Tardive tourettism
What are features of tardive dyskinesia?
Orobuccolingual, trunal or choreiform movements:
- Vacuous chewing
- Lip smacking/pouting
- Grimacing facial movements
What are features of tardive dystonia?
Sustained, sterotyped muscle spasms of a twisting or turning character e.g. retrocollis and back arching/opisthotonic posturing
What is tardive akasthisia?
Sense of restlessness or unease +/- repetative, puposeless movements (e.g. pacing)
How would you treat tardive dyskinesia?
Gradually withdraw neuroleptics and wait 3-6 months
What is the defintion of dystonia?
Prolonged muscle contraction causing abnormal posturing or repetitive movements
What is a primary dystonia?
Where dystonia is the only/main clinical manifestation
What is secondary dystonia?
Dystonia caused by a disease process e.g. brain injury, cerebral palsy or drugs
What is torticollis?
Dystonic spasms gradually develop in neck muscles causing the head to turn (torticollis) or to be drawn backwards (retrocollis). There may also be a jerky head tremor. A gentle touch with a finger tip at a specific site may relieve the spasm temporarily (sensory trick or ‘geste’).
What is blephorospasm?
These consist of spasms of forced blinking or involuntary movement of the mouth and tongue (e.g. lip-smacking and protrusion of the tongue and jaw).
What is writer's cramp?
A specific inability to perform a previously highly developed repetitive skilled movement, e.g. writing. The movement provokes dystonic posturing. Other functions of the hand remain normal. Overuse may lead to task-specific dystonias in certain occupations, e.g. musicians, typists and even golfers.
What are examples of focal dystonias?
- Spasmodic torticollis
- Writer's cramp
What are acute dystonic reactions?
Reactions which can occur on starting new medicaitons. Following features present:
- Oculogyric crisis
What is trismus?
What is oculogyric crisis?
Bilateral elevation of the visual gaze, but several other responses are associated with the crisis
What drugs can cause acute dystonic reactions?
- Antiemetics — e.g. metaclopramide, proclorperazine
- Antidepressants and serotonin receptor agonists — e.g. SSRIs, buspirone, sumitriptan
- Antibiotics — e.g. erythromycin
- Antimalarials — e.g. chloroquine
- Anticonvulsants — e.g. carbamazepine, vigabatrin
- H2 receptor antagonists — e.g. ranitadine, cimetidine
- Recreational drugs — e.g. cocaine
How would you manage an acute dystonic reaction?
What is huntington's disease?
A dominantly inherited neurodegenerative condition that produces progressive movement disorder and dementia
What is the cause of huntington's chorea?
Genetic mutation of huntingtin gene, with extra triplet repeates of glutamine - trinucleotide repeat expansion disease. This produces an expanded polygluatmine protein. The mutated protein aggregates in the caudate and putamen, which causes neuronal cell death. This stops inhibition of movements, leading to chorea and other movement disorders
How is huntington's disease inherited?
What is the relationship between number of repeat sequences in huntingtin gene and age of onset?
More repeats, earlier onset of disease
What is the phenomenon of anticipation seen in huntington's disease?
A tendency for successive generations to have earlier onset and more severe disease due to unstable CAG repeat expansion during meiosis (particularly when inherited from the father)
What are the main features of huntington's chorea?
- Personality changes
- Movement disorder - chorea, athetosis
- Bizarre gait
- Abnormal eye movements
- Poor coordination
What neurotransmitters are affected in huntington's chorea?
- Decreased GABA
- Decreased Acetylcholine
- Increased Dopamine