Neurology Flashcards
Which body parts fall into the territory of the anterior cerebral artery in the sensory and motor cortices?
Trunk, legs, feet
Which body parts fall into the territory of the middle cerebral artery in the sensory and motor cortices?
Arms, head and neck
What fasciculi are within the dorsal column? Which is medial and which is lateral?
Medial = Gracile fasciculus Lateral = Cuneate fasciculus
What sensory/motor role does the dorsal column have?
Fine touch + proprioception (sensory)
Where does the sensory input for the gracile fasciculus of the dorsal column come from?
Lower limbs
Where does the sensory input for the cuneate fasciculus of the dorsal column come from?
Upper limb
What are the 3 neurones involved in the dorsal column tract?
Dorsal root ganglion - gracile/cuneate nucleus (medulla)
Gracile/cuneate nucleus - ventral posterolateral thalamus
ventral posterolateral thalamus - post-central gyrus
Describe the path of the first neurone in the dorsal column tract
Sensory neurones in limbs and dorsal root gangion outside spinal cord
Enters gracile and cuneate fasciculi in spinal cord
Goes up to ipsilateral gracile and cuneate nuclei in medulla oblongata
Describe the path of the second neurone in the dorsal column tract
Gracilie/cuneate nuclei - decussates in pyramids
Travels through medial lemniscus of the pons
Reaches ventral posterolateral nucleus of thalamus
Describe the path of the third neurone in the dorsal column tract
Ventral posterolateral nucleus of thalamus to post-central gyrus in brain (sensory cortex)
What role does the spinothalamic tract have?
Pain, temperature and crude touch (sensory)
Where are the 3 neurons in the spinothalamic tract?
Sensory neuron/dorsal root gangion - dorsal horn of grey matter
Dorsal horn - contralateral thalamus
Thalamus - post-central gyrus
Describe the path of the 1st neuron of the spinothalamic tract
Sensory neuron/dorsal root ganglion
Enters spinal cord through Lissauer’s fasciculus
Ascends in spinal cord by 1 or 2 segments
Synapses in dorsal horns of grey matter
Describe the path of the 2nd neuron of the spinothalamic tract
Dorsal horn of grey matter - decussates in Anterior White Commissure at same level
Ascends through spinal cord and brain stem
Synapses at thalamus (contralateral to dorsal horn)
Describe path of 3rd neuron of spinothalamic tract
Thalamus to post-central gyrus
What is the role of the corticospinal tract?
Axial and limb motor
What is the role of the lateral corticospinal tract?
Limb motor
What is the role of the anterior corticospinal tract?
Axial motor
Describe the path of the lateral corticospinal tract
Pre-central gyrus (motor cortex) - internal capsule - brainstem
75-90% corticospinal tract decussate at pyramids (lateral corticospinal)
Descend through spinal cord and synapse at anterior horn cell
Lower motor neuron from anterior horn cell to limb muscles
Describe the path of the anterior corticospinal tract
Pre-central gyrus (motor cortex) - internal capsule - brainstem
10-25% do not decussate at pyramids (anterior corticoospinal)
Descend to level in spinal cord where decussates through anterior white commissure
Synapses at contralateral anterior horn cell
Lower motor neuron from anterior horn cell to axial muscles
Give 4 nerve endings for fine touch
Pacinian corpuscle
Meisner’s corpuscle
Ruffini endings
Merkel endings
What 3 tests do you do for a mini neurological exam?
General appearance + vital signs
GCS
Lateralising signs
Pupil reflexes
What are the 3 domains of the Glasgow Coma Scale?
Best Motor Response
Best Verbal Response
Best Eye-opening Response
Which of the 3 domains of the Glasgow Coma Scale is the best prognostically?
Best Motor Response
What might you do if patient is unconscious to assess them?
Collateral history
Mini Neurological Exam
GCS
Pupils
What are the criteria for the scores on BMR of GCS?
6 = obeys commands 5 = Localises to pain 4 = Flexes to pain 3 = spastic flexion/withdrawal (don't use) 2 = Extends to pain 1 = None
What do lateralising signs tend to indicate? Give examples of lateralising signs
One hemisphere lesion
E.g. gaze paresis, inattention to one side, upper limb drift, asymmetrical flexion/extension
What causes a fixed dilated pupil?
Compression of parasympathetic fibres on outside of CN3, usually over petrous temporal bone
What shape does a subdural bleed show on imaging? Why?
Crescent-shaped
Low pressure venous blood causes slow bleed
What shape does an extradural bleed show on imaging? Why?
Convex shaped
Needs high pressure arterial blood to peel periosteal dura off cranium
What does a subarachnoid haemorrhage present with?
Sudden onset, severe headache - pressure on meninges
Nausea, vomiting, stiff neck, photophobia, restless, agitation
May have seizures
What symptom might an occipital lobe lesion cause?
contralateral visual defect
What might occur with dominant parietal lobe syndrome?
Confusion
Difficulty writing and reading (agraphia)
Difficulty with mathematics (acalculia)
Visuospatial impairment - 3D (agnosia)
Apraxia - inability to comprehend verbal commands and motor impairment
Contralateral sensory impairment
Where is Broca’s area? What is its role?
Dominant hemisphere frontal lobe (usually left)
Speech production
Where is Wernicke’s area? What is its role?
Dominant hemisphere temporal lobe (usually left)
Surrounds auditory cortex, close to lateral fissure
Comprehension of speech
What might frontal lobe lesions present with?
Bilateral lesion = personality
Unilateral lesion = hemiparesis
What might temporal lobe lesions present with?
Memory loss - verbal memory loss if dominant hemisphere, non-verbal if non-dominant
What is the general role of the basal ganglia? How might problems present?
General role = control of movement and reward
Too much control = rigidity
Too little = chorea
What is the most likely cause of sudden onset hemiparesis? Where do most of these originate?
Stroke
More are ischaemic - embolic from carotid bifurcation (75%) or from heart (25%)
What would occur if a middle cerebellar artery stroke happened? What happens instead?
MCA stroke = unconscious
Most strokes in this territory are perforator artery emboli affecting internal capsule
Where is the lesion in myelopathy?
Spinal cord
What are the features of the A fibres in peripheral nerves?
Long, fast, myelinated
Role: proprioception, vibration, fine touch
What are the features of the C fibres in peripheral nerves?
Short, slow, non-myelinated
Role: pain, crude touch, temperature
Which nerve fibres are affected first in diabetic peripheral neuropathy? What test of sensation is most sensitive for peripheral neuropathy?
A fibres - long fibres affected first
Therefore - VIBRATION test - picks up neuropathy before symptoms/numbness appears
What is the most common cause of spinal cord lesions?
Disc osteophytes from arthritis
Give a rhyme for proximal muscle weakness. What are the presenting features?
Can’t do hair, stair, chair
Weak grasp, handwriting and flapping gait - finer movements lost first
Fatigue
Where is the lesion in a radiculopathy?
Nerve root - initial segment of a nerve leaving the spinal cord
Where is the most common cervical radiculopathy? Give the dermatome and myotome distributions of these nerve roots.
C6 and C7
C6 dermatome = thumb, myotome = biceps
C7 dermatome = middle and index finger, myotome = triceps
Where are the most common lumbar radiculopathies? What are the dermatomes and myotomes affected for these nerve roots?
L5 and S1
L5 dermatome = big toe, dorsal foot
Myotome = dorsiflexion of foot (stand on heels)
S1 dermatome = ltitle toe, lateral and sole of foot
Myotome = plantar flexion foot
What features might suggest cerebellar lesion?
IPSILATERAL dysdiadochokinesia, ataxia, nystagmus, intention tremor, slurred speech, hyperreflexia (drunk)
Where are the most common sites for compression if these cranial nerves are affected together?
a) CNIII, IV, VI
b) CNVII, VIII
c) CNIX, X, XI, XII
a) cavernous sinus
b) petrous part of temporal bone
c) jugular foramen
What are features of an intracranial mass?
epilepsy
focal neurological signs
raised intracranial pressure - headache, dizziness, nausea, vomiting, blurred vision
What is the commonest cause of proximal myopathy? How might you test for proximal myopathy clinically?
Corticosteroid use e.g. transplant, chemotherapy, autoimmune
Stand on one leg and squat
If there is a lesion at a disc level, which nerve root will be affected?
Nerve root below
e.g. disc lesion at C6/C7 - present with C7 radiculopathy
What are other ways of saying “long tract signs”?
UMN, pyramidal, descending tract, corticospinal tract signs
Give some examples of long tract signs
spastic gait hypertonia, hyperreflexia clonus + babinski cross-adductors Hoffman's sign loss of fine finger movements Deltopectoral reflex
What frequency is vibration sensation measured at?
128Hz
Where should pain stimulus in Best Motor and Best Eye response for GCS be done?
to CN distribution so not to elicit spinal reflex
e.g. behind ear and mastoid bilaterally
What is the formula for cerebral perfusion pressure? What should cerebral perfusion pressure be?
CPP = mean arterial pressure - intracranial pressure
Should be 60-70mmHg
Describe the relationship between intracranial volume and intracranial pressure
Little increase in ICP with increasing volume until decompensates
Then exponential large increase in ICP with small increase in volume
How long do the majority of seizures last for?
1-2 minutes
Give the management of a seizure
Time it! Insert nasopharyngeal airway and oxygen mask, monitor O2 sats
If >10 minutes - IV midazolam
Loading dose: IV phenytoin, valproate, levotiracetam 15 min infusion with cardiac monitoring
Give post-seizure management
U+Es
Possibly CT head
Beware of peri-ictal aspirations and risk of LRTI
What drug can you use for acute management of raised ICP?
Mannitol - 100ml 10% or 50ml 20%
When might hydrocortisone cover be given?
If on long-term corticosteroids, cover with hydrocortisone to prevent adrenal crisis
When might dexamethasone be given? What cautions need to be taken?
Given peri-operatively for tumour neurosurgery
Discontinue after 2 weeks (avoid Cushings)
Monitor blood glucose - risk hyperglycaemia
Beware of steroid psychosis
What risks do anticoagulants and anti-platelets have in neurology? How would you manage these?
Increased risk intracranial haemorrhage and chronic subdural bleeds
If pathology found, stop meds, and reverse acutely
Discuss with haematologist and only re-start if agreed by neurosurgeon
Give the pathophysiology of cranial diabetes insipidus. Give management
Decreased ADH secretion - can be feature of hypopituitarism
Excessive diuresis, thirst and hypernatraemia
Give diuresis post-surgery
Fluid-balance chart, drink to thirst, consider desmopressin
Why might hyponatraemia occur in neurology?
Water moves into plasma from cells e.g. cerebral oedema, raised ICP
Brain injury releases natriuretic peptides causing “cerebral salt wasting”
SIADH
What are the effects of hyponatraemia?
potentially life-threatening >48hrs or severe
Seizures, coma, cardio-respiratory arrest
Chronic: falls, gait problems, concentration and cognitive decline, osteoporosis
How would you manage hyponatraemia?
IV crystalloid and consider mineralocorticoid
If SIADH, either fluid restriction OR sodium replacement
Careful - Too rapid Na replacement risks central pontine myelinosis
How might you manage neuropathic pain?
Trial and error with neurotropics
Gabapentin + pre-gabalin for radicular pain
Carbamazepine - trigeminal neuralgia
Topirimate - chronic refractive head pain
Give the total capacity of the CSF and of the ventricles
CSF total = 120ml
Ventricles = 20ml
Give 3 functions of CSF
Protection (cushion)
Buoyancy - reduces pressure on base of brain
Environment for brain function and neurotransmission e.g. low K
What lines the ventricles and what produces CSF?
Ependymal cells
Choroid plexus produces CSF
What foramen connects 1st and 2nd ventricles to the 3rd?
Foramen of Monro
Where is the 3rd ventricle and what connects it to the 4th ventricle?
Between left and right thalamus
Connects to 4th via CEREBRAL AQUEDUCT
Where is the 4th ventricle and how does it drain to spinal canal and subarachnoid cisterns?
4th ventricle between pons and medulla
Drains laterally via Foramina of Luschka and foramen of Magendie medially
Give some presenting features of myelopathy
Back pain
Long tract signs - UMN signs
Loss of fine finger movements
Radiating limb pain
Give features of vertebral syndrome
Lower back pain - dull, aching
Radiating pain not as far as radiculopathy
Give features of radiculopathy
Sensory loss/pain in dermatome AND/OR motor loss in myotome
Possible back pain
What difference in presentation is there between L5 radiculopathy and common peroneal nerve palsy?
L5 radiculopathy - weakness on foot inversion
common peroneal nerve palsy - weakness on foot eversion
Give the features of Brown-Sequard syndrome
Lesion in one half of spinal cord
Ipsilateral UMN weakness below lesion
Ipsilateral loss of fine touch, proprioception and vibration below lesion
Contralateral loss of pain, temp and crude touch 1-2 segments below lesion
What is paracellar syndrome and what features present?
Pituitary tumour or mass in pituitary cellar
Upward pressure on optic chiasm - bitemporal hemianopia
Hypopituitarism
What are the 2 types and relative prevalence of strokes?
Ischaemic (85%)
Haemorrhagic (15%)
(also can be due to systemic hypoperfusion)
What is the WHO definition of a stroke
Clinical syndrome consisting of RAPIDLY developing clinical signs of focal (or global in coma) disturbance of cerebral function lasting MORE THAN 24 HRS or leading to death with no apparent cause other than a VASCULAR origin
Given common symptoms of an anterior/carotid circulation stroke
Weakness (face, legs, arms)
Impaired speech/language
Amaurosis fugax
Give common symptoms of a posterior circulation stroke
Dysarthria Dysphagia Diplopia Dizziness Ataxia Diplegia
Give the 3 types of ischaemic stroke
Embolic
Thrombotic
Systemic hypoperfusion
What does the acute CT scan show after a stroke? Why might a repeat CT be done after 48hrs?
Acute - bleeds/haemorrhagic stroke
Ischaemia appears normal, but after 48hrs may see dark patches
What arteries supply anterior circulation?
Internal carotid arteries - ACA and MCA
What arteries supply posterior circulation?
Posterior cerebral artery and vertebral arteries
What arteries connect anterior and posterior circulations?
Posterior communicating arteries
What criteria defines a total anterior circulation infarct?
Contralateral weakness/sensory loss
Homonymous Hemianopia/visual inattention
Higher cortical dysfunction - dysarthria, dysphasia
What criteria defines a partial anterior circulation infarct?
2 of the following:
Contralateral weakness/sensory loss
Homonymous hemianopia/visual inattention
Higher cortical dysfunction - dysarthria, dysphasia
What are the presenting features of a posterior circulation infarct?
Cranial nerve palsy Contralateral sensory/motor deficit (pyramidal lesion) Cerebellar dysfunction Isolated homonymous hemianopia Bilateral events - reduced GCS
What is a lacunar infarct?
= occlusion of deep penetrating arteries
Why does a lacunar infarct not present with higher cortical features?
Only affect small volumes of SUB-cortical white matter so does not present with cortical features e.g. dysarthria, dysphasia, visual field loss
What syndromes are common in lacunar infarcts?
pure motor hemiparesis Ataxic hemiparesis "clumsy hand" + dysarthria pure hemisensory loss Mixed sensorimotor
Why do small lacunar infarctions cause large clinical syndromes?
White matter infarcts - nerve fibres narrowed down so small area has large clinical consequences
What is the acute management of a stroke?
ABCDE + bloods (including BM!)
Hx: TIME of onset, risk factors, contraindications to thrombolysis, blood pressure, NIHSS
Urgent CT head (no contrast within 1h) BEFORE thrombolysis/aspirin
Thrombolysis/thrombectomy OR Aspirin 300mg
What might be the next stage and long-term management of a stroke?
Investigate cause (full history, exam, investigations)
Screen and prevent complications (infection, sores)
Secondary prevention (lifestyle, meds, surgery)
Rehabilitation (PT/OT/SLT)
What is the NIHSS?
National Institute of Health Stroke Scale
Score 0-42
Grades severity of stroke and can use to monitor response to acute treatment
How might ischaemic regions appear on an acute CT?
May not be visible
Subtle blurring and decreased attenuation of grey-white junction due to oedema may be early sign
May see hyperdense vessel - sign of intravascular clots e.g. MCA
What type of infarcts are MRIs better at viewing?
Posterior circulation infarcts
Lacunar infarcts
Give the indications for thrombolysis post-stroke
Within 4.5 hours of symptom onset
Non-haemorrhagic stroke on CT
Give some contra-indications for thrombolysis
Haemorrhagic stroke/bleed current or previous anti-coagulation/coagulopathy pregnancy high blood pressure Aneurysm Severe liver disease, varices, portal HTN Seizures at presentation Hypo/erglycaemia Intracranial neoplasm history Rapidly improving symptoms
What is given for thrombolysis? How should you follow up this treatment?
IV Tissue Plasminogen Activator (ALTEPLASE 0.9mg/kg)
Monitor blood pressure and complications of bleeding
24hr CT to check for haemorrhagic transformation
Give the indications and methods for thrombectomy
Indications - within 6 hours of symptom onset in anterior circulation, later if basilar thrombosis.
Methods - CT angiography to remove clot, can be used alongside thrombolysis
What are the 2 parts of ischaemic cerebral tissue called and which is more likely to survive when blood supply returns?
Ischaemic core (central) surrounded by Ischaemic Penumbra (outer) Core dies 1st, but penumbra may live if blood supply returned The smaller the core, the better
What investigations might you do to investigate the cause of the stroke?
Bloods: FBC, UE, ESR, Lipids, LFTs, CRP, clotting, glucose/Hba1c
ECG + 72 hour tape (paroxysmal AF)
Carotid Doppler USS (carotid stenosis)
Echo (endocarditis/valvular disease)
MRI (confirm diagnosis, infarcts) or delayed CT if not tolerated
What appears white in a
a) T1 weighted image?
b) T2 weighted image?
a) fat
b) water
What is the best type of MRI for detecting acute infarcts?
Diffusion-weighted MRI - infarct appears WHITE
What type of MRI is matched with DW MRIs to detect infarcts?
ADC - infarct appears BLACK
Match black lesion to white lesion on DW MRI
DWI-ADC match
Give examples of MDT management post-stroke
nursing
PT, OT, SLT, dietitian, orthoptics
What lifestyle advice might you give someone after a stroke?
smoking cessation limit alcohol and drug use dietary modifications exercise driving advice
What medications might you give as secondary prevention for strokes?
Anti-platelets - Aspirin 300mg for 2 weeks, then Clopidogrel lifelong
Anticoagulation: if have AF (HASBLED vs CHADSVASC score to determine this)
Anti-hypertensives: if haemorrhagic, be careful if ischaemic - aim <130/80
Statins - aim 40% decrease in non HDL cholesterol
How might you surgically manage extracranial carotid stenosis?
If 70-99% occluded - carotid endarterectomy
If 50-69% occluded - consider CEA or carotid artery stenting
How could you manage malignant MCA syndrome?
Decompressive hemicraniotomy
How could you manage posterior circulation infarct surgically?
External ventricular drainage or Posterior fossa decompression to prevent risk of hydrocephalus
What are the different methods of management for haemorrhagic stroke?
Manage hydrocephalus
Reversal of anticoagulation
Blood pressure control
What are the indications for medical and surgical management of haemorrhagic stroke?
Small deep haemorrhages, lobar haemorrhage without hydrocephalus, rapid neurological deterioration, large haemorrhage and significant comorbidities before stroke, GCS <8, posterior fossa haemorrhage
What are the indications for reversal of anticoagulation in haemorrhagic stroke management?
Primary intracerebral haemorrhage and taking anticoagulants with elevated INR
What are the indications for rapid blood pressure lowering in acute management of haemorrhagic stroke?
Within 6 hours symptom onset
systolic BP 150-220
Consider if >6hrs or BP>220
Aim systolic 130-140 within 1h and maintain for 7 days
What are the contraindications to rapid blood pressure lowering in management of haemorrhagic strokes?
Underlying structural cause
GCS<6
Awaiting neurosurgery for haematoma
Massive haematoma with poor prognosis
What medications can be used for reversal of anticoagulation in haemorrhagic stroke management?
Warfarin - Beriplex and vit K
LMWH - protamine
DOACs - Beriplex partial
Dabigatran - Idaruciumab
What causes can mimic stroke presentations?
Seizures Tumours/abscess Migraine Metabolic Functional Myelopathy, peripheral neuropathy, cranial nerve
What might you want to determine about the distribution and pattern of muscle weakness and why?
Proximal (muscle) or distal (nerve)
Symmetrical (genetic/metabolic) or asymmetrical
Mono or poly
Cranial involvement (bulbar/ophthalmoplegia)
Variability (fatigueability/relapse-remission)
Sensory deficit?
Give clinical features of Motor neurone disease and exclusion criteria
UMN (+LMN)
No sensory deficit or sphincter disturbance
Never affects eye movements
What are the 4 types of motor neuron disease? Which is the most common?
Most common = amyotrophic lateral sclerosis (ALS)
Progressive bulbar palsy
Progressive muscular atrophy
Primary lateral sclerosis (rare)
What are the pathophysiological features of MND?
Loss of motor neurones in cortex, cranial nerve nuclei and anterior horn cells
Where are the loss of motor neurones in ALS and what symptoms appear?
Loss motor neurons in motor cortex AND anterior horn cell
UMN+LMN signs
Worse prognosis if bulbar onset, older age, reduced FVC
Where are the loss of neurons in progressive bulbar palsy?
Cranial nerves 9-12
UMN (corticobulbar) and LMN (bulbar)
Where are the loss of neurons in progressive muscular atrophy? What type of signs do you see?
Anterior horn cell loss
LMN signs only
Where is loss of neurons in primary lateral sclerosis and what signs do you get?
Loss of Betz cells in motor cortex
Mainly UMN
Pseudobulbar palsy
Spastic leg weakness
What is the classical presentation of someone with MND?
Usually >40 (median 60yrs) Stumbling spastic gait Footdrop +/- proximal myopathy Weak grip/shoulder abduction Aspiration pneumonia UMN+LMN, potential bulbar signs Frontotemporal dementia in 25%
How is MND diagnosed?
By EXCLUSION
Brain/cord MRI to exclude structural
LP to exclude inflammatory
Nerve conduction studies - detect loss of motor neurones and exclude mimicking motor neuropathies
What is the prognosis of MND?
Poor, <3 years in 50% patients
How would you manage MND?
MDT approach
Riluzole - NMDA receptor antagonist, improves survival slightly
Supportive
What supportive measures might you need to do for someone with MND?
excess saliva - positioning, suction, oral care, anti-muscarinics, botulinum toxin A
dysphagia - blend food, gastrostomy
Spasticity - baclofen, exercise, orthotics
communication - SLT, alternative methods
palliative care - from diagnosis!
ventilation - if wanted, only increases prognosis few months
Give 3 branches of peripheral nerve disease
Polyneuropathy
Mononeuropathy
Mononeuritis multiplex