neuro Flashcards
RFs subarachnoid haemorrhage
PKD smoking alcohol HTN cocaine connective tissue disesase: Marfan's, Ehlers-Danlos
thunderclap heaedache
subarachnoid
high impact trauma → brain haemorrhage
extradural
oculomotor nerve palsy presentation
eye "down + out" ptosis dilated pupil (mydriasis)
horner’s syndrome presentation
ptosis (partial)
constricted pupil (miosis)
anhydrosis
same side as lesion
cerebellar signs
ipsilateral dysdiadochokinesia + dysmetria ataxia nystagmus intention tremor slurred staccato speech hypotonia
presentation parkinson’s disease
bradykinesia resting pill-rolling tremor stooped posture cogwheel rigidity hypomimesis
CT scan lenticular vs crescent shape hyperdensity
lenticular = extradural crescentic = subdural
UMN signs
weakness
hyperreflexia (Babinski’s, clonus)
hypertonia (spasticity)
LMN signs
weakness + wasting hyporeflexia hypotonia flaccidity fasciculations
facial nerve palsy presentation
idiopathic LMN facial nerve palsy
facial weakness (NOT forehead sparing), drooling
hyperacusis (stapedius paralysis)
loss of taste (anterior 2/3 of tongue)
inability to close eye (tearing / drying)
loss of corneal reflex
Bell’s phenomenon: eyeball rolls up but eye remains open when trying to close eyes
normal sensation
myasthenia gravis vs lambert eaton
MG: muscle fatigue w use
ocular involvement
assoc w thymoma
AChR Ab
LE: may have autonomic involvement
anti-VGCC Ab
assoc w small cell lung cancer
investigations multiple sclerosis
bloods: FBC, ESR / CRP, LFTs, U+Es, B12
Gadolinium enhanced MRI brain + spinal cord (gold standard)
lumbar puncture → electrophoresis → IgG Ab in CSF form oligoclonal bands
visual evoked potentials → delayed conduction velocity
causes of parkinson’s plus
Lewy body dementia multiple system atrophy progressive supranuclear palsy corticobasal degeneration vascular parkinsonism
Parkinson’s disease management
medical:
dopamine agonists e.g. bromocriptine
L-dopa e.g. sinemet + domperidone / carbidopa (reduce peripheral SEs e.g. N&V)
COMT / MAO-B inhibitors (dopamine degrading enzymes)
surgical: deep brain stimulation
causes of cerebellar syndrome
demyelination: MS
alcohol
infarct: stroke / TIA
space-occupying lesion e.g. vestibular schwannoma
inherited: Friedrich’s ataxia, wilson’s disease
epilepsy medication: phenytoin
multiple system atrophy
management multiple sclerosis
conservative: MDT approach, stress reduction, smoking cessation, pt education
medical:
acute: IV methylprednisolone 3-5days
relapse prevention (disease modifying drugs DMDs): β-IFN, biologics (natulizumab, rituximab), mitoxantrone
symptomatic:
spasticity: baclofen / botox
urinary: CISC, anti-Ach (oxybutynin)
neuropathic pain: gabapentin
depression: SSRIs, psychological therapies
classification multiple sclerosis
progressive relapsing (pt declines w each relapse) secondary progressive (relapse / remission ends and pt suddenly declines) primary progressive (no relapse / remission) 80% relapsing-remitting (relapses may or may not leave permanent deficits) clinically isolated syndrome (1st episode + signs consistent w MS on MRI)
2 main types of stroke + RFs for each
ischaemic: embolic / small or large vessel atherosclerosis
haemorrhagic: HTN, aneurysm / AVM rupture, trauma, altered haemostasis
acute management stroke
urgent CT head → exclude haemorrhage
ischaemic:
< 4.5hrs (hyperacute) → thrombolysis: IV alteplase
consider thrombectomy <6hrs for severe stroke
> 4.5hrs → aspirin 300mg (2nd line clopidogrel)
repeat CT after 24hrs to reconfirm no haemorrhage
haemorrhagic:
refer to neurosurgery for coiling of aneurysms / decompressive hemicraniectomy
ongoing management post-stroke
cons: MDT approach (incl. SALT swallow assessment)
RF modification: exercise, diet, smoking cessation
medical:
antiplatelet therapy: clopidogrel
if AF → warfarin (start after 2wks)
manage CV RFs: statin, anti-HTN, treat diabetes
surgical: endovascular stenting, carotid endarterectomy (stenosis > 70%)
management TIA
all pts seen within 7 days
if ABCD2 score (risk of stroke) > 3 → see within 24hrs
cons: RF modification
med: RF modification (treat HTN + diabetes)
statin + clopidogrel 75mg OD
warfarin if AF
surg: carotid endarterectomy: if stenosis > 70%
corticospinal tract function
descending tract
motor
pyramidal decussation in medulla
spinothalamic tract function
ascending tract
pain, temperature
decussates at level of innervation
dorsal columns function
ascending tract
light touch, proprioception, vibration
decussation in medulla
presentation anterior cord syndrome (Beck’s)
preservation of dorsal columns (light touch, proprioception, vibration)
loss of spinothalamic (temperature, pain) contralateral
UMN signs below lesion
LMN signs at level of lesion
presentation Brown-Sequard
hemisection of spinal cord
ipsilateral motor UMN signs below lesion / LMN at level of lesion
ipsilateral loss of light touch, proprioception, vibration
contralateral pain / temp loss (spinothalamic)
presentation central cord syndrome
central corticospinal damage → motor loss affecting arms > legs
spinothalamic + dorsal tract damage → loss of pain, temp, proprioception, light touch, vibration
cauda equina presentation
back pain / sciatica areflexia (ankle jerk) flaccid LL weakness saddle anaesthesia bowel / bladder dysfunction
investigations for guillain barre
bloods: FBC, CRP / ESR, culture → infection
stool MC+S → infection
antiganglioside Ab
imaging to exclude other problems
lumbar puncture → raised CSF protein, normal WCC
spirometry → reduced FVC
nerve conduction studies → reduced velocity
typical Hx extradural haemorrhage
head trauma (pterion) blackout on impact, lucid interval, deterioration
typical Hx subdural haemorrhage
fluctuating consciousness
alcoholics / elderly (brain atrophy pulls on venous sinuses)
source of bleed in extradural haemorrhage
middle meningeal artery (beneath pterion)
differentials for tremor
resting tremor: parkinsonism, benign essential tremor, drugs e.g. antipsychotics, beta-agonists
intention tremor: cerebellar syndrome
postural tremor:
thyrotoxicosis, caffeine, anxiety, same drugs as above
typical presentation lewy body dementia
visual hallucinations
fluctuating memory problems / cognitive impairment
parkinsonism
causes of unilateral ptosis
Horner’s (constricted pupil, partial ptosis)
oculomotor nerve palsy (dilated pupil, complete ptosis)
stroke
myaesthenia gravis
congenital e.g. simple congenital myogenic ptosis, myotonic dystrophy
causes of bilateral ptosis
myaesthenia gravis
guillain-barre syndrome
myotonic dystrophy
innervation of upper limb reflexes
biceps: C5/6
triceps: C7
supinator: C6
reflex grading
0 = absent 1+ = present only w reinforcement 2+ = normal 3+ = hyperactive w/o clonus 4+ = hyperactive w clonus
MRC power scale
0 No contraction
1 Flicker or trace of contraction
2 Active movement, with gravity eliminated
3 Active movement against gravity
4 Active movement against gravity and resistance
5 Normal power
innervation of lower limb reflexes
patellar: L3-4
achilles: S1-2
lower limb + upper limb dermatomes
upper: C5, C6, C7, C8, T1
lower: L1, L2, L3, L4, L5, S1
myaesthenia gravis aetiology vs lambert eaton
MG: autoimmune neuromuscular disease w Ab against AchR (affects postsynaptic membrane of NMJ)
LEMS: autoimmune against VGCC (voltage-gated calcium channels)
investigations myaesthenia gravis
bloods: CK (exclude myopathy), AchR Ab, MuSK Ab, anti-VGCC Ab (Lambert-Eaton), TFTs
Tensilon test: trial short acting anticholinesterase → ↑ACh → transient symptom improvement
lung function testing → reduced FVC
CXR / CT thorax → exclude thymoma / lung Ca
nerve conduction testing → reduced muscle action potential with stimulation
EMG → ↓response to repetitive stimulation →↑single-fibre jitter
management acute myaesthenic crisis
ABCDE
IVIg / plasmaphoresis
prednisolone
monitor FVC → intubation / ventilation
management chronic myaesthenia gravis
anticholinesterases e.g. pyridostigmine (symptomatic only)
immunosuppression: prednisolone (2nd line: azathioprine, ciclosporin)
thymectomy
types of motor neurone disease
primary lateral sclerosis (UMN)
progressive muscular atrophy (LMN)
amyotrophic lateral sclerosis (UMN + LMN)
progressive bulbar palsy (LMN IX-XII)
management motor neurone disease
supportive management
cons: MDT, palliation, psychosocial support, physiotherapy, OT, etc.
med: riluzole (prolongs life slightly but no improvement in function / QOL)
baclofen → spasticity
NIV → resp failure
anti-muscarinic e.g. atropine → salivation
dietician → diet modification, PEG / NG feeding → dysphagia, weight loss
causes of unilateral facial nerve palsy
UMN: stroke LMN: idiopathic: Bell's palsy Ramsay-Hunt syndrome (VZV → painful vesicles) infection e.g. otitis media parotid mass cancer e.g. acoustic neuroma
management facial nerve palsy
cons: ENT / neuro / ophthamology involvement
eyelid taping, lubricating eye drops, protective glasses
med: high dose prednisolone within 72hrs
surg: if corneal damage → lateral tarsorrhaphy (suturing of lateral parts of eyelids)
facial nerve decompression: middle fossa craniotomy via mastoid bone
causes of horner’s syndrome
1st order: stroke, MS, syringomyelia, encephalitis
2nd order: pancoast syndrome, cervical rib
3rd order: carotid aneurysm / dissection, cavernous sinus thrombosis
investigations for horner’s syndrome
cocaine drop test: failure of dilatation (normal: cocaine blocks NA reuptake at NMJ → pupil dilatation / Horner’s: lack of NA → no dilatation)
CXR → pancoast tumour
CT / MRI brain / spinal cord → stroke, inflammation, spinal cord lesions
carotid angio
causes of bilateral facial nerve palsy
sarcoidosis GBS lyme disease bilateral acoustic neuroma (neurofibromatosis type 2) Bell's palsy
presentation neurofibromatosis type 1
cafe au lait spots (>5 >15mm / >5mm if pre-pubertal) Lisch nodules (iris) axillary (Crowe's sign) / inguinal freckling neurofibromas of skin learning disability epilepsy scoliosis phaeochromocytoma
presentation neurofibromatosis type 2
schwanommas / meningiomas / gliomas → hearing loss, tinnitus, balance problems, headache, facial pain / numbness
causes of diplopia
CN palsies (3,4,6) SOL multiple sclerosis myaesthenia gravis myotonic dystrophy GBS BPPV
causes of 3rd nerve palsy
medical: ischaemic / vascular (diabetes, HTN, vasculitis, MS)
surgical: compression (emergency → refer to neurosurg)
trauma, SOL, cavernous sinus thrombosis, posterior communicating artery aneurysm
causes of 4th / 6th nerve palsy
trauma
SOL
ischaemic / vascular: HTN, diabetes, vasculitis
MS
management acute myasthenic crisis
plasmaphoresis / IVIg
prednisolone
monitor FVC and consider intubation / ventilation
definition clinically isolated syndrome (MS) + prognosis
isolated ep of MS Sx w consistent changes on MRI
60-80% progress to MS
causes of hearing loss
conductive: wax, foreign body, otitis media, otosclerosis
sensorineural: age-related, ototoxic drugs e.g. gentamicin, Menieres, acoustic neuroma, infection (meningitis)
visual pathway
optic nerve → optic chiasm → optic tract → parietal (upper) radiation / temporal (lower) radiation → occipital visual cortex
lesion of optic nerve
ipsilateral monocular visual loss
lesion of optic chiasm
bitemporal hemianopia
pituitary tumour, craniopharyngioma
lesion of optic tract
contralateral homonymous hemianopia
lesion of parietal optic radiation
contralateral inferior homonymous quadrantopia
lesion of temporal optic radiation
contralateral superior homonymous quadrantopia
lesion of occipital visual cortex
macula sparing contralateral homonymous hemianopia
internuclear ophthalmoplegia: definition, features, differentials
lesion of medial longitudinal fasciculus (connects CNIII, IV, VI)
ipsilateral failure of adduction
contralateral horizontal nystagmus on abduction
MS, vascular disease
causes of dysarthria
motor speech impairment UMN (pseudobulbar): stroke, MS, MND LMN (bulbar): myasthenia gravis, GBS, MND cerebellar basal ganglia: Parkinson's (hypokinetic)
receptive aphasia: definition, cause
lesion affecting Wernicke’s area (temporal)
fluent meaningless speech w neologisms, word substitutions
impaired comprehension
expressive aphasia: definition, cause
lesion affecting Broca’s area (frontal)
incomprehensible speech, comprehension intact
conductive aphasia: definition, cause
lesion affecting arcuate fasciculus (connect’s Broca’s + Wernicke’s areas)
comprehension intact, speech fluent, cannot repeat words / phrases
global aphasia: definition, cause
affects Broca’s, Wernicke’s + arcuate fasciculus
severe expressive + receptive aphasia
features Friedrich’s ataxia
autosomal recessive bilat cerebellar ataxia mixed UMN + LMN signs (LL > UL) areflexia, wasting, spastic weakness loss of vibration sense, proprioception, light touch (dorsal columns) kyphoscoliosis pes cavus high-arched palate assoc w HOCM, diabetes,
features Charcot-Marie-Tooth
hereditary peripheral neuropathy (CMT1+2 autosomal dominant)
pes cavus, foot drop, hammer toes
stork-leg deformity / inverted champagne bottle leg (distal muscle wasting)
distal muscle weakness + atrophy
hyporeflexia
causes of bilateral UMN lesion
MS
spinal cord lesion
MND
cerebral palsy
causes of unilateral UMN lesion
stroke
SOL
MS
causes of bilateral LMN lesion
symmetrical + distal = peripheral neuropathy: diabetes, alcohol, GBS, CMT
symmetrical + proximal = myopathy: myotonic dystrophy, myasethenia gravis, dermatomyositis / polymyositis
asymmetrical: mononeuritis multiplex (SLE, RA, vasculitis)
causes of unilateral LMN lesion
anterior horn: polio
radiculopathy: disc herniation, OA
peripheral nerve lesion e.g. carpal tunnel, common peroneal nerve lesion
plexus lesion e.g. Erb’s / Klumpke’s palsy
causes of mixed UMN + LMN signs
MND
vit B12 deficiency
Friedreich’s ataxia
infection e.g. west nile, diptheria
presentation syringomyelia
cape-like loss of temp, neuropathic pain, paraesthesia
spastic weakness UL > LL
wasting of small muscles of hand
bowel / bladder dysfunction
preservation of dorsal columns until late
causes of hydrocephalus
50% idiopathic
communicating:
↓absorption: meningitis, post-haemorrhagic
↑production: choroid plexus tumour (rare)
non-communicating (obstruction): tumours, SAH, intraventricular haemorrhage, congenital (e.g. aqueduct stenosis)
management hydrocephalus
ABCDE
referral to neurosurgery
acute: external ventricular drain
long-term: ventriculoperitoneal shunt
glasgow coma scale
eyes (4): normal, to sound, to pain, none
motor (5): normal, localises to pain, flex from pain, abnormal flexion (decorticate), abnormal extension (decerebrate), none
verbal (6): normal, confused, inappropriate words, incomprehensible sounds, none
management guillain barre syndrome
supportive management IVIg / plasmapheresis monitor FVC: intubation / ventilation analgesia physiotherapy (prevent flexion contractures) thromboprophylaxis
causes of peripheral neuropathy
motor: CMT, GBS, lead poisoning
sensory: diabetes, alcohol, B12 / thiamine deficiency, leprosy
autonomic: diabetes, alcohol, amyloidosis
mononeuritis multiplex
definition + causes
isolated damage to at least 2 separate nerve areas
vasculitis, Sjogrens, RA, sarcoidosis, SLE
presentation wernicke’s encephalopathy vs korsakoff’s
wernicke’s:
ataxia
mental stage changes (confusion, altered consciousness)
eye signs: ophthalmoplegia, nystagmus
korsakoffs': agnosia anterograde amnesia aphasia apraxia confabulation deficit in executive functions
presentation of ulnar nerve palsy
claw hand: flexion of 4th + 5th fingers (passive extension only)
wasting of hypothenar eminence + dorsal interossei
loss of sensation / paraesthesia 1.5 medial fingers (dorsal + palmar)
ulnar paradox
injury to ulnar nerve proximal to elbow → reduced clawing
causes of ulnar nerve palsy
more common at elbow than wrist
compression in cubital tunnel / guyon canal
trauma: elbow dislocation, supracondylar fractures, self-harm at wrist
degenerative arthritis
what muscles does the median nerve innervate in the hand
LOAF: lateral 2 lumbricals opponens pollicis abducens pollicis flexor pollicis brevis
lacunar infarct definition + Bamford classification criteria
involves perforating arteries (branches of MCA)
1 of the following:
1. unilateral weakness (+- sensory deficit) of arm + face, arm + leg or all 3
2. pure sensory stroke
3. ataxic hemiparesis
posterior circulation infarct definition + Bamford classification criteria
involves vertebrobasilar arteries 1 of the following: 1. cerebellar / brainstem syn 2. loss of consciousness 3. isolated homonymous hemianopia
lateral medullary syndrome presentation + affects which arteries?
posterior inferior cerebellar artery / vertebral artery infarct (AKA Wallenberg syn) ipsilateral facial numbness contralateral limb sensory loss nystagmus + ataxia Horner's syndrome
anterior vs middle cerebral artery infarcts
anterior: leg > arm, personality changes, loss of judgement / social behaviour
middle: arm > leg, aphasia (wernicke’s / broca’s)
types of seizures
generalised (both hemispheres, loss of consciousness):
tonic / clonic / tonic-clonic / myoclonic / atonic / absence
partial / focal: simplex / complex (impaired consciouness)
management status epilepticus (incl doses)
ABCDE (incl. oxygen)
- buccal midazolam (10mg) / IV lorazepam (2-4mg)
- IV lorazepam (repeat)
- IV phenytoin
- rapid induction of GA (at 30min)
management epilepsy
cons: MDT, driving advice, medical bracelets
med: refer to neurologist for anti-epileptics
carbamazepine → focal seizures
sodium valproate → generalised seizures
lamotrigine if child-bearing age
surg: lobectomy / hemispherotomy (disconnection of hemispheres) - uncommon
meningitis CSF findings
bacterial: turbid, neuts, ↓↓glucose, ↑↑protein
viral: clear / cloudy, lymphocytes, normal glucose, ↑protein
TB / fungal: clear / cloudy, lymphocytes, ↓glucose, ↑protein
meningitis management (incl doses)
ABCDE
empirical IV ceftriaxone (2-4g) + IV dexamethasone (10mg)
if in community IM / IV benpen
causes of meningitis
viral (most common): enterovirus, influenza, HSV
bacterial: neisseria meningitides, strep pneumo
fungal: crytococcus
contraindications to lumbar puncture
raised ICP (coning)
sepsis
coagulopathy
cutaneous lesion: superficial infection, spina bifida
investigations meningitis
bedside: lumbar puncture
bloods: FBC, CRP, U&Es, culture, glucose, clotting, meningococcal PCR, ABG
imaging: CT head (check for raised ICP)
causes of encephalitis
viral: HSV (most common), arbovirus
bacterial: neisseria meningitides, syphilis, listeria
TB
parasitic
prion disease
encephalitis diagnostic criteria
major: altered mental status > 24hrs w no other cause
minor: > 2 for possible / > 3 to confirm
fever, seizures, new focal neurology, CSF ↑WBC, abnormality on imaging / EEG
management of raised ICP
ABCDE
head elevation 40degrees to aid CSF outflow
manage seizures
analgesia + sedatives
IV mannitol / hypertonic saline via central line (risk of rebound ↑ICP)
neurosurgery: surgical evacuation, ventricular drainage, burr hole / craniotomy to decompress
axillary nerve injury
nerve roots
causes
motor + sensory deficits
C5-C6
shoulder dislocation
surgical neck of humerus fracture
iatrogenic (rotator cuff repair)
deltoid wasting + paralysis: reduced abduction
teres minor paralysis: reduced external rotation
loss of regimental patch (lower 1/2 of deltoid)
presentation of Erb’s palsy
waiter’s tip: internally rotated shoulder, pronated forearm, flexed wrist
sensory loss over C5/C6
loss of biceps reflex / moro reflex
causes of Erb’s palsy
over-flexion of the neck:
fall onto neck
traumatic vaginal delivery
presentation of Klumpke’s palsy
claw hand
(wrist extension, MCP hypertension, DIP + PIP flexion)
supinated forearm
C8, T1 sensory loss (pinky finger + medial forearm)
causes of Klumpke’s palsy
over-abduction of shoulder:
falling with arm gripping overhead
traumatic vaginal delivery
complications of SAH
rebleeding (30%) vasospasm → ischaemia hydrocephalus SIADH seizures
presentation / associations myaesthenia gravis vs LEMS
MG: muscle weakness w use eye Sx: ptosis, diplopia, complex ophthalmoplegia bulbar Sx: dysphagia, dysarthria resp involvement assoc w thymoma
LEMS: muscle weakness improves w use
autonomic Sx: dry mouth, constipation, hypotension, blurred vision
assoc w small cell lung carcinoma
