Week 17 - Nervous System Flashcards
What are the 2 main types of stroke?
Ischaemic
Haemorrhagic
What are some common symptoms of a stroke?
Typically asymmetrical
- limb weakness
- facial weakness
- dysphagia
- visual field defects
- sensory loss
- ataxia
- vertigo
What defines a TIA?
Temporary neurological dysfunction (<24hrs)
Caused by ischaemia but without infarction
What are crescendo TIAs?
2 or more TIAs within a week
What can be the causes of ischaemia in a stroke?
Embolism
Thrombosis
Systemic hypoperfusion
Cerebral venous sinus thrombosis
What is the classification system of Ischaemic stroke? What are the types?
Bamford classification
- total anterior circulation stroke
- partial anterior circulation stroke
- posterior circulation syndrome
- lacunae stroke
What is the criteria for a total anterior circulation stroke?
All 3 of the following must be present:
• Unilateral weakness (and/or sensory deficit) of the face, arm and leg
• Homonymous hemianopia
• Higher cerebral dysfunction (dysphasia, visuospatial disorder)
What is the criteria for a partial anterior circulation stroke?
2 of the following need to be present:
• Unilateral weakness (and/or sensory deficit) of the face, arm and leg
• Homonymous hemianopia
• Higher cerebral dysfunction (dysphasia, visuospatial disorder)*
What is the criteria for posterior circulation syndrome?
1 of the following needs to be present:
• Cranial nerve palsy and a contralateral motor/sensory deficit
• Bilateral motor/sensory deficit
• Conjugate eye movement disorder (e.g. horizontal gaze palsy)
• Cerebellar dysfunction (e.g. vertigo, nystagmus, ataxia)
• Isolated homonymous hemianopia
What is the criteria for a lacunae stroke?
1 of the following needs to be present:
• Pure sensory stroke
• Pure motor stroke
• Sensori-motor stroke
• Ataxic hemiparesis
What is a total anterior circulation stroke?
Large cortical stroke affecting the areas of the brain supplied by both the middle and anterior cerebral arteries
What is a partial anterior circulation stroke?
Less severe form of TACS
Only part of the anterior circulation has been compromised
What is posterior circulation syndrome?
Involves damage to the area of the brain supplied by the posterior circulation e.g. Cerebellum and brainstem
What is a lacunar stroke?
Subcortical stroke
Occurs secondary to small vessel disease
No loss of higher cerebral function
What are the 2 subtypes of haemorrhagic stroke?
Intracerebral haemorrhage
Subarachnoid haemorrhage
What is the most common cause of a subarachnoid haemorrhage?
Berry aneurysm in the circle of Willis
Where do posterior cerebral arteries supply?
Mixture of medial and lateral areas of the posterior cerebrum
Where do the middle cerebral arteries supply?
Majority of the lateral cerebellum
Where do the anterior cerebral arteries supply?
Ateromedial area of the cerebrum
What symptoms are seen in a blockage of the anterior cerebral artery?
Weakness of contralateral leg
Behaviour changes
Typically present with weakness and sensory loss in the lower leg and foot opposite the lesion, incontinence and behaviour changes
What symptoms are seen in a blockage of the middle cerebral artery?
Weakness of contralateral face and arm
Speech disturbance
Visual field defect
Intattention to stimuli
Sensory defecits
Typically present with symptoms most associated with stroke
What symptoms are seen in the blockage of the posterior cerebral artery?
Visual field defects
Sensory defecits
What symptoms are seen with a lesion in the vertebrobasilar system?
Dizziness
Ataxia
Impaired balance
Pupil and eye movement abnormalities
Changes in voice and swallowing
Weakness and sensory changes
Decreased level of consciousness
What is found in grey matter?
Cell bodies
Cerebral cortex
What is found in the white matter?
Glial cells and myelinated axons
What are the 4 lobes of the brain?
Frontal
Parietal
Temporal
Occipital
What is the function of the frontal lobe?
Higher intellect
Personality
Mood
Social conduct and language
Where is the broca region located?
Frontal lobe
What is the function of the parietal lobe?
Language
Calculation
Visuospatial function
What is the function of the temporal lobe?
Memory
Language
Hearing
Where is wernickes area located?
Temporal lobe
What is Broca’s area for?
Language retrieving
What is wernickes area for?
Language articulating
What is the function of the occipital lobe?
Vision
What is the function of the pons?
Handles unconscious processes and jobs
E.g. sleep wake cycle, breathing
What is the function of the medulla?
Helps control vital processes
E.g. heartbeat, breathing, BP
What is the function of the cerebellum?
Helps maintain balance and posture
What is the secondary prevention after someone’s had a stroke?
Clopidogrel 75mg once daily
Atorvostatin 20-80mg (delayed to at least 48 hours after event)
BP and diabetes control
Manage modifiable risk factors e.g. smoking, obesity and exercise
What are the driving restrictions after a stoke?
Not allowed to drive for 1 month
Don’t need to tell DVLA if it’s TIA or Ischaemic stroke
Need to notify DVLA if it’s a haemorrhagic stroke
Should always personally tell DVLA of attack especially if HGV driver
What is the function of the primary motor cortex when communicating with corticospinal tract?
Execution of movement
What is the function of the premotor cortex when communicating with the corticospinal tract?
Control of behaviour especially of trunk muscles
What is the function of the supplementary motor cortex when communicating with the corticospinal tract?
Stabilisation and coordination of the body during bimanual movements
Where do nerves of the lateral corticospinal tract cross?
Medulal
Where do nerves of the anterior corticospinal tract cross?
At level the spinal nerves enter
Where do UMN and LMN synapse in the corticospinal tract?
Ventral horn
Where do UMNs from the trigeminal (corticobulbar) tract arise?
Lateral aspect of the primary motor cortex
Where do nerves of the trigeminal (corticobulbar) tract supply?
Muscles of head and neck
What are the 3 layers of the meninges?
Dura mater - adhears to skull
Arachnoid Mater - directly beneath dura
Pia mater - adhears to brain and spinal cord
What are the 2 functions of the meninges?
Provide a supportive framework for vessels
Form distinct comoartments to prevent injury
Where is CSF produced?
Choroid plexus
What is the function of CSF in the ventricles of the brain?
Protect brain against trauma
Provide nutrients
Removes waste product
What connects the lateral ventricles to the 3rd ventricle?
Interventricular foramina
Where CSF reabsorbed?
Arachnoid granulations
What type of cells are found in the choroid plexus?
Cuboidal epithelial cells
What is the main Thrombolysis given in Ischaemic stroke?
Alteplase
What 2 conditions must be met before giving Alteplase Thrombolysis in a stroke event?
Must be administered within 4.5hrs of stroke symptoms
Haemorrhage must be definitively excluded
What are the most common causes of an UMN lesion?
Stroke
MS
B12 deficiency
Brown-sequard syndrome
Trauma
Tumours
Severe infection
Dementia
What does babinskis sign show?
UMN lesion
What are some clinical signs of an UMN lesion?
• Disuse atrophy (minimal) or contractures
• Increased tone (spasticity/rigidity) +/- ankle clonus
• Pyramidal pattern of weakness (extensors weaker than flexors in arms, and vice versa in legs)
• Hyperreflexia
• Upgoing plantars (Babinski sign)
What 2 features are associated with an UMN lesion and which 2 are associated with a LMN lesion?
UMN = hypertonia, spastic paralysis
LMN = hypotonia, flaccid paralysis
What are some causes of LMN lesions?
Trauma to peripheral nerves
Viruses that attack ventral horn cells
What clinical signs are seen in a LMN lesion?
• Marked atrophy
• Fasciculations
• Reduced tone
• Variable patterns of weakness
• Reduced or absent weakness
• Downgoing plantars or absent response
What symptoms does damage to Broca’s area cause?
○ Dysfluency
○ Impaired grammatical structure
○ Absence of small linking words
○ Slow, but comprehensible speech
What symptoms are seen when there is damage to wernickes area?
○ Fluent speech lacking in meaningful content
○ Patients unaware of the scale of their aphasia
What is the angular gyrus responsible for?
Reading and writing
Allows us to associate multiple types of language related info
What symptoms are seen in damage to the angular gyrus?
○ Alexia - inability to recognize or read written words or letters, typically as a result of brain damage
○ Agraphia - inability to write letters, symbols, words, or sentences, resulting from damage to various parts of the brain.
What is dysdiadochokinesia?
Inability to do rapid alternating movements
What is the most common cause of a subarachnoid haemorrhage?
Uncontrolled hypertension
What is the first investigation done in suspected stroke?
Non contrast CT head
Rule out haemorrhage
What is the suggested treatment for Bell’s palsy?
Prednisolone 30mg if symptoms presented in last 72hrs
