Movement Disorders 1 Flashcards
2 medications associated with chorea?
OCP
Dopamine agonists
2 toxic causes of chorea?
Alcohol
Carbon monoxide poisoning
2 metabolic disturbances associated with causing chorea?
Hypocalcaemia
Hyperthyroidism
What is the genetic basis of Huntington’s disease?
Prolonged CAG triplet repeat in the huntingtin gene, found on chromosome 4
Where is the major pathology in Huntington’s Disease?
The striatum (caudate nucleus and putamen), in turn affecting corticostriatal projections
What reflexes are present in Huntington’s Disease?
Primitive reflexes - pout, grasp, palmomental
Extensor plantars
What MRI sign may be present in Huntington’s disease?
Increased T2 signal in caudate nucleus
What is an unequivocally normal CAG triplet repeat length?
Less than 26 repeats
What is an unequivocally abnormal CAG triplet repeat length?
Over 40
What do intermediate CAG triplet repeat lengths signify (26-40)?
Reduced penetrance
What might a huge CAG triplet repeat length result in?
Juvenile onset/Westphal variant HD - onset less than 20 with a more pronounced akinetic-rigid presentation
What is interesting about the inheritance of Westphal HD?
Typically paternally inherited
4 medications of use to treat chorea?
Tetrabenzene
Phenothiazones e.g. Risperidone
Benzodiazepines
Haloperidol
What is Sydenham’s chorea?
Post GAS (strep pneumoniae) infection, like a subacute rheumatic fever (weeks to months after primary infection)
What is the pathophysiology behind Sydenham’s chorea?
Necrotising arteritis in thalamus, caudate nucleus and putamen
Can Sydenham’s chorea recur? When?
Yes - during pregnancy or occasionally intercurrent infection
At what stage of pregnancy is chorea gravidarum most likely to occur?
First trimester
What comprises the pyramidal system?
Motor cortex
Corticospinal columns
What comprises the Extrapyramidal system?
Paired subcortical masses/basal ganglia - caudate nucleus, putamen, globus pallidus, subthalamic nuclei and substantia nigra
What part of the brain projects information between the basal ganglia and the motor cortex?
Thalamus
What cells are reduced in number in the substantia nigra pars compacta in PD?
Neuromelanin cells
What dopaminergic receptor changes occur in striatal cell membranes in PD?
Reduced D1 and D2 receptor expression
What 2 Sx may precede the movement disorder in PD?
Constipation
Anosmia
Describe the typical Parkinsonian tremor?
Coarse, slow (4-7Hz) resting tremor
Initially unilateral, often in hands, before spreading to all 4 limbs later
Improves with movement, worse with stress
Disappears when asleep
Where is the rigidity prominent in PD (in terms of affected muscle groups)?
Flexors - arms, legs, trunk, neck
What eye signs may occur in PD?
Loss of ocular convergence
Loss of upward gaze
What autonomic symptoms may occur in PD?
Postural hypotension
Constipation
Seborrhoea
Do sleep problems occur in Parkinson’s?
They can do - REM sleep behavioural disorders
What is the role of SPECT/DAT D2 receptor imaging in differentiating PD from PD mimics?
Normal scan in PD or normal phenotype
Abnormal in PD mimics
What is the role of FP-CIT SPECT in differentiating between PD, mimics and non-PD?
Normal in non-PD
Abnormal in PD and its mimics
Give 6 PD mimics?
Multiple systems atrophy (MSA) Progressive supranuclear palsy PSP Vascular Parkinsonism Cortico-basal ganglionic degeneration Wilson's disease Drug induced Parkinsonism
3 types of MSA?
MSA-A(utonomic) - bladder/bowel, postural hypotension, REM sleep disturbances etc. Most prominent
MSA-P(arkinsonism) - Extrapyramidal symptoms most prominent
MSA-C(erebellar) - ataxia, bilateral UMNL signs, cerebellar signs
Eye Sx of PSP?
SN gaze palsy - downward eye movement initially impaired, followed by all other voluntary eye movements
Lid retraction common
Non-eye Sx of PSP?
Extrapyramidal dysfunction Axial/truncal dystonia UMNL signs Dementia Reduced response to L-Dopa
What about the distribution of Sx may suggest vascular Parkinsonism?
Predominantly lower limbs affected
Sx of CBD?
Asymmetric akinetic-rigid syndrome Marked dyspraxia Myoclonus Dementia Alien hand phenomena relatively common
What is dystonia?
Sustained abnormal posturing due to contraction of large muscle groups
What is cervical dystonia, or spasmodic torticolis?
Primary focal dystonia of sternocleidomastoid
Causes unilateral head deviation to face opposite side of affected dystonic SCM
What is geste antagoniste?
Touching the unaffected side of the chin of a torticolis patient may return head back to normal
How is torticolis managed?
Botox injections into affected SCM
What is Meige’s syndrome?
Cervical dystonia + oromandibular dystonia; blepharospasm and mouth/tongue/jaw dystonia
What is dopamine-responsive dystonia?
Childhood-onset dystonia that affects the legs only
Responds to L-Dopa long term
What drug class commonly causes acute dystonic reactions? How do you manage them?
Phenothiazines e.g. Haloperidol, metaclopramide
Give Anticholinergics e.g. Procyclodine
Why does tardive dyskinesia occur?
Long term neuroleptic treatment leads to dopamine depletion and subsequent development of abnormal supersensitive DA receptors
How does tardive dyskinesia often manifest?
Orofacial dyskinesia
Choreoathetoid limb movements
3 causes of athetosis?
Hypoxic brain damage/cerebral palsy
Kernicterus
Metabolic storage disorders
Relative to the side of the affected subthalamic nucleus or connections, where does Hemiballismus occur?
Contralateral to the affected side
Most common causes of Hemiballismus?
POCS vascular disease
MS
DM - HHS
What motor GCS score does decorticate posturing represent?
3
What does a motor GCS 3 correspond to?
Decorticate posturing
Describe decorticate posturing?
Flexed elbows, wrists, fingers
Extended and internally rotated legs
What is the biphasic pathogenesis of decorticate posturing?
Lesions above red nucleus causes its disinhibition and thus rubrospinal tract activation -> medullary reticulospinal activation leading to upper limb flexion
Disruption of lateral corticospinal tract which gives a pyramidal weakness in lower limbs
What type of posturing will a lesion of motor tracts above the red nucleus cause?
Decorticate posturing
What type of posturing will a lesion of motor tracts at or below the red nucleus cause?
Decerebrate posturing
What motor GCS score does decerebrate posturing imply?
2
What type of posturing is suggested by a motor GCS of 2?
Decerebrate posturing
Describe decerebrate posturing?
Extended upper and lower extremities
Arched back and head
What type of posturing would a brainstem lesion typically cause?
Decerebrate posturing
Why does a brainstem lesion cause decerebrate posturing?
The red nucleus remains inactivated, and thus so does the rubrospinal tract - no upper limb flexion + usual pyramidal weakness of lower limbs
What does progression from decorticate to decerebrate posturing suggest?
Tonsilar herniation
What is opisthotonos caused by?
Extrapyramidal effect caused by axial spinal muscle spasm
Caused in turn by inactivation of inhibitory corticoreticular fibres which act upon the pons/reticular formation
5 causes of opisthotonos in kids?
Meningitis Tetanus Kernicterus MSUD Sandifer syndrome