Neuro Flashcards
Define stroke
Sudden onset of focal neurological symptoms caused by interruption of the vascular supply to part of the brain, or intracerebral haemorrhage
Define epilepsy
Episodes of increased electrical activity within the brain leading to recurrent seizures
What is ataxia?
Loss of coordination of movements
What is rigidity?
Hypertonia characterised by increased resistance to passive stretch
Where is lumbar puncture performed and why?
What is the major contraindication and why?
Between L3 and L4 - spinal cord ends at L1
RICP - risk of tonsillar herniation
Where does an extradural haemorrhage occur?
Where does the blood come from?
Describe 2 radiological features
- Between the skull and the dura mater (or really between the periosteal and meningeal layers of dura mater)
- Arterial - usually middle meningeal artery
Why is extradural haemorrhage more likely to occur in younger patients?
In older people, the dural layers are more adhesive - less likely to split apart
Between which meningeal layers does a subdural haemorrhage occur?
Where does the blood come from?
- Meningeal layer of dura, and arachnoid mater
- Venous - bridging veins which drain from cerebrum into DVSs
What is it called if blood accumulates in the subarachnoid space?
What is the most likely cause?
What is the typical presenting feature?
- Subarachnoid haemorrhage
- Rupture of berry aneurysm
- Thunderclap headache
From which vessel does the anterior cerebral circulation originate?
What about the posterior circulation?
- ICAs
- Vertebral arteries
Outline the course of the ICAs in terms of landmarks and major branches
- Enters cranial cavity via carotid canal
- Passes through cavernous sinus - pierces dura - enters middle cranial fossa
- Gives off:
ophthalmic artery
posterior communicating artery
anterior cerebral artery - Continues as middle cerebral artery
Which areas are supplied by the anterior cerebral artery?
What would the symptoms be if it was occluded unilaterally?
Medial aspects of frontal and parietal lobes, and corpus collosum
Contralateral lower limb motor and sensory deficit
Which areas does the middle cerebral artery supply?
What would be the symptoms of unilateral occlusion?
- Lateral surfaces of cerebral hemispheres
- Occlusion causes contralateral sensory and motor deficit, particularly upper limb
- Contralateral hemianopia
Outline the course of the vertebral arteries in terms of landmarks and major branches
- Ascend in transverse foramina
- Enter via foramen magnum
- Give off
Anterior and posterior spinal arteries to SC
Posterior inferior cerebellar artery (PICA)
Which areas are supplied by the PICA?
What would happen in occlusion?
- Lateral medulla and cerebellum
- Contralateral loss of pain and temp
- Ipsilateral nystagmus/ataxia, Horner’s, dysphagia
What happens in occlusion of one of the vertebral arteries?
Usually anastomoses mean it’s fine
Which arteries converge to form the basilar artery?
Vertebral arteries
What does the basilar artery supply?
What would be the symptoms of occlusion?
Cerebellum and pons
Very serious - often coma, bilateral motor and sensory deficit, cerebellar signs, CN signs
How does the basilar artery terminate?
Bifurcates into posterior cerebral arteries
Which areas does the PCA supply?
Posterior hemispheres - posterior parietal and occiptal
Name 3 major vessels which could be occluded in a posterior circulation stoke
- Vertebral
- Basilar
- PCA
Which modalities are carried by the dorsal columns?
Fine (tactile) touch
Vibration
Proprioception
2-point discrimination
Where are the cell bodies of the 1st order neurones of the DCML?
Dorsal root ganglion
In which dorsal column do fibres from the upper body run?
Lower body?
Upper = lateral Lower = medial
In Brown-Sequard syndrome, why are DCML modalities lost ipsilaterally?
Lesion occurs below the level of decussation - decussation occurs in medulla, but lesion is in SC
Give some examples of causes of DCML lesion
Vitamin B12 deficiency
Tabes dorsalis
Which modalities are carried by the lateral and anterior spinothalamic tracts respectively?
Lateral - pain and temperature
Anterior - crude touch and pressure
In Brown-Sequard syndrome, why are the spinothalamic tract modalities lost contralaterally?
Lesion occurs above the level of decussation
What is Brown-Sequard syndrome?
Hemisection of the spinal cord resulting in:
- Ipsilateral loss of vibration/proprioception/fine touch
- Contralateral loss of pain and temperature sensation
- Ipsilateral UMN signs
What is syringomyelia?
CSF cyst in central canal of spinal cord resulting in selective loss of bilateral lateral spinothalamic tracts - hence loss of pain and temp in both upper limbs.
What is an upper motor neurone?
A motor neurone whose cell body is in the cortex, and whose axon remains in the CNS
What is a lower motor neurone?
A motor neurone whose cell body is int he ventral horn of the spinal cord (or brainstem) and whose axon projects to the musculature
What gives rise to extrapyramidal signs?
Damage to basal ganglia
Give some examples of extrapyramidal signs
- Resting tremor
- Cog-wheel rigidity
- Bradykinesia
- Festinating gait
What are pyramidal signs?
UMNL signs
Give some signs of cerebellar dysfunction
- Dysdiadochokinesia
- Ataxia
- Nystagmus
- Intention tremor
- Slurred speech
- Hypotonia
Give some causes of cerebellar dysfunction
- Posterior fossa tumour
- Alcohol
- MS
- Trauma
- Rare
- Inherited - e.g. Friedrich’s ataxia
- Epilepsy medication
- Stroke
Are cerebellar symptoms contralateral or ipsilateral?
Ipsilateral
What are the 4 cardinal signs of Parkinsons?
- Bradykinesia
- Rigidity
- Postural instability
- Resting tremor
List 6 UMN signs
- Hyperreflexia
- Hypertonia
- Positive Babinski
- Clonus
- Pronator drift
- Clasp-knife reflex
List 5 LMN signs
- Hyporeflexia
- Hypotonia
- Wasting
- Weakness
- Fasciculations
What produces the hyperreflexia in an UMN lesion?
Lack of descending inhibition
What is clonus?
Repetitive, sustained plantarflexion when the ankle is suddenly, passively dorsiflexed
What causes clasp-knife rigidity?
Activation of the Golgi tendon organ causing subsequent sudden relaxation while a spastic muscle is passively stretched
What is pyramidal weakness?
Weakness affecting extension of upper limbs and flexion of lower limbs
Describe decorticate posturing
Where is the lesion?
Legs extended at knee and ankle
Elbows and wrists flexed
Lesion above the red nucleus
Describe decerebrate posturing
Where is the lesion?
Everything extended
Forearm pronated
Lesion below red nucleus
What is a positive rhombergs?
Unsteady with eyes shut - sign loss of proprioception - problem with dorsal columns
Shows sensory ataxia (whereas in negative rhomberg’s the ataxia is cerebellar)
List some features of a Broca’s aphasia
- Staccato speech
- Lack of fluency
- Understand question, problem is with expression - hence can write down answer
List some features of a Wernicke’s aphasia
- Fluent and grammatical speech, just doesn’t make sense
- Inappropriate answers to questions
- No problem with expression - problem is comprehension
List some signs of a basal skull fracture
- Periorbital ecchymosis
- Mastoid ecchymosis
- CSF rhinorrhoea/otorrhoea
