T2 L9 Parkinson's disease Flashcards
What is ballismus?
High amplitude flailing of limbs on one side of the body
What is the pathophysiology of ballismus?
Inhibition of STN so no excitatory signals are produced to GPi so GPi does not inhibit thalamus so thalamus excites cortex
What is the commonest cause of ballismus?
Stroke
What is a tic?
Brief, repetitive stereotypic movements with premonitory urge
What are the types of tics?
Simplex: blinding, coughing
Complex: jumping or twirling
Plus: motor disorder
Coprolalia: swearing
What can help reduce tics?
Distraction & concentration
What can make tics worse?
Anxiety
Fatigue
What is Tourette syndrome?
More severe expression on a spectrum of tic disorders
What other conditions are associated with tics?
50% have ADHD
33.3% have OCD
≥50% have anxiety
What are come causes of tic disorders?
Complex genetic inheritance
Post infectious immune
What is chorea?
Jerky, brief, irregular contractions that aren’t repetitive or rhythmic
Appear to flow from one muscle to the next
Patient appears fidgety / restless
What is the pathophysiology of chorea?
Inhibition of STN –> no excitation signal produced to GPi so no signal to thalamus which causes it to excite cortex
What are some causes of chorea?
Huntington’s disease
Drugs- neuroleptics
What is the genetics of Huntington’s disease?
Trinucleotide repeat on chromosome 4
Autosomal dominant with complete penetrance
Longer the repeat sequence the earlier the disease presents
Normal is 10-28 repeats
Disease is 36-121 repeats.
What is the clinical presentation of Huntington’s disease?
Cognitive - inability to make decisions, multitasking, slowness of thought
Behavioural -irritability, depression, apathy, anxiety, delusions
Physical - chorea, motor persistence, dystonia, eye movements
What is myoclonus?
Brief movement
Rapid onset & offset
Positive or negative
What is the pathophysiology of myoclonus?
Unknown
Possible imbalance between excitatory & inhibitory neurotransmitters as it is treatable with anti epileptic drugs
Perturbations of motor control system leading to brief disequilibrium which explains why it is present at multiple levels
What are the causes of myoclonus?
Juvenile myoclonic epilepsy
Brain hypoxia
Prion disease
What is dystonia?
Abnormal twisting posture associated with jerky tremor
Often axial, facial, trunk
What is the pathophysiology of dystonia?
Unknown
Functional PET studies suggested abnormal activity in motor cortex, supplementary areas, cerebellum & basal ganglia
Abnormal activity in basal ganglia suggested by dystonia being caused by blocking dopamine receptors & some dystonia being levodopa responsive