Neurology Flashcards
(232 cards)
What is the location of a Lumbar Puncture?
Between L3 and L4
What is the function of the Cerebellum?
Control of motor function and maintenance of muscle tone
What are the 3 functional and anatomical divisions of the cerebellum?
Cerebrocerebellum - Planning movements, motor learning and coordination of muscle activation
Spinocerebellum (vermis + intermediate zone) - Body movements and receives proprioceptive information
Vestibulocerebellum (flocculonodular) - Balance control and ocular reflexes e.g. fixation on a target. Receives input from the vestibular system.
What is the blood supply to the cerebellum?
Superior Cerebellar Artery (SCA) and Anterior Inferior Cerebral Artery (AICA) from BASILAR ARTERY
Posterior Inferior Cerebellar Artery (PICA) from VERTEBRAL ARTERY
What are the causes of cerebellar dysfunction? (PASTRIES)
Posterior fossa tumour Alcohol misuse Stroke Trauma Rare causes Inherited - Friedrich’s Ataxia Epilepsy medications Sclerosis (MS)
What are the symptoms of cerebellar dysfunction? (DANISH)
Dysdiadochokinesia and Dysmetria
Ataxic gait
Nystagmus
Intention tremor
Slurred speech
Hypotonia
What is dysdiadochokinesia and what is dysmetria?
Dysdiadochokinesia = impaired rapidly alternating movements
Dysmetria = past pointing
Which part of the cerebellum is damaged to give dysdiadochokinesia, dysmetria, ataxic gait and intention tremor?
Spinocerebellum
Basilar infarct/ SCA/ AICA
Which part of the cerebellum is damaged to give Nystagmus?
Vestibulocerebellum
PICA infarct
Are cerebellar signs contralateral or ipsilateral and why?
Ipsilateral
What is the function of the basal ganglia?
Regulation of movement by providing a feedback mechanism to the cerebral cortex
Where is the basal ganglia located?
Forebrain and midbrain
Part of the extrapyramidal system
How does the extrapyramidal system differ to the corticospinal tracts?
Involuntary actions whereas corticospinal is voluntary
What is the direct pathway?
Excitatory
Excitation of the striatum = ↑ inhibition of the Globus Pallidus Interna and Substantia Nigra
↓ inhibition of the Thalamus (as GPi and SNR inhibit thalamus) = ↑ excitation of the motor cortex
Movement!
What is the indirect pathway?
Inhibitory
Excitation of the striatum = ↑ inhibition of the Globus Pallidus Externa
↓ inhibition of the Subthalamic nucleus (as GPe inhibits STN)
↑ excitation of the Substantia Nigra (as STN excites)
↑ inhibition of the Thalamus (as SNR inhibits) = ↓ excitation of the motor cortex
↓ movement
What is the function of the direct and indirect pathways?
Regulation between the two pathways is what allows control and coordination of movement
What is the pathophysiology behind Parkinson’s disease?
The degradation of dopaminergic neurones in the Substantia Nigra Pars Compacta
Lewy bodies are also present in the basal ganglia, brain stem and cortex
Leads to dysregulation between the direct and indirect pathways
What is the Parkinsonism triad?
Resting tremor - pill rolling
Hypertonia - Cogwheel Rigidity (hypertonia + tremor)
No muscle weakness
Bradykinesia
How does bradykinesia present in PD?
Slow to start moving
Slow actions that decrease in amplitude upon repetition e.g. Micrographia
Festinant gait (shuffling, forward leaning)
Might stop in doorways
Reduced facial expressions
What are the autonomic effects of PD?
Postural hypotension
Constipation
Dribbling
What are the neuropsychiatric effects of PD?
Depression
Psychosis
How is PD mainly diagnosed?
Clinical diagnosis
Triad is progressive and signs are usually worse on one side
Which drugs must be excluded when diagnosing PD?
Psychiatric drugs - typical antipsychotics/ methyldopa/ memantine
Anti-emetics e.g. metoclopramide
Which other conditions must be excluded when diagnosing PD?
Wilson’s disease
Non-Parkinson’s dementias e.g. Dementia with Lewy Bodies, Frontotemporal dementia
Other tremor causes e.g. essential Tremor