neuro Flashcards
nerve malfunction: demyelination
- schwann cell damage leads to myelin sheath disruption
- results in marked slowing of conduction
- seen for example- in guillain-barre syndrome
nerve malfunction: axonal degeneration
- axon damage causes the nerve fibre to die back from periphery
- conduction velocity initially remains mortal because axonal continuity is maintained in surviving fibres
- typically occurs in toxic neuropathies
nerve malfunction: compression
- focal demyelination at point of compression causes disruption of conduction
- typically occurs in entrapment neuropathies
nerve malfunction: infarction
-micro infarction of vasa nervorum occurs in diabetes and arteritis
nerve malfunction: infiltration
infiltration occurs by inflammatory cells in leprosy and granulomas such as sarcoid and neoplastic cells
nerve malfunction: wallerian degeneration
process that results when a nerve fibre is cut and distal part of the axon that is separated from neurone’s cell body degenerates
neuropathy
pathological process affecting a peripheral nerve or nerves
mononeuritis multiplex
means that several individual nerves are affected
mononeuropathies
process affects a single nerve
carpal tunnel syndrome
most common mononeuropathy and entrapment neuropathy
carpal tunnel syndrome: pathology
results from pressure and compression on the median nerve as it passes through carpal tunnel in the wrist
carpal tunnel syndrome: epidemiology
more common in females
females have narrower wrists but same sized tendons
usually in those >30 y/o
carpal tunnel syndrome: causes
usually idiopathic
carpal tunnel syndrome: associations
hypothyroidism diabetes mellitus pregnancy (3rd trimester) amyloidosis obesity rheumatoid arthritis acromegaly
carpal tunnel syndrome: risk factors
diabetes
carpal tunnel syndrome: presentation
- aching pain in hand and arm, especially at night
- paraesthesiae (tingling or prickling) in thumb, index, middle + 1/2 ring fingers, and palm
carpal tunnel syndrome: differentials
peripheral neuropathy
motor neurone disease
MS
carpal tunnel syndrome: electromyography
shows slowing of conduction velocity in median sensory nerves across carpal tunnel
helps confirm lesion site and severity
carpal tunnel syndrome: phalen’s test
patient can only maximally flex wrist for 1 minute
carpal tunnel syndrome: tinel’s test
tapping on the nerve at the wrist induces tingling
carpal tunnel syndrome: treatment
wrist splint at night
local steroid injection
decompression surgery
mononeuropathies: ulnar nerve (C7-T1)
vulnerable to elbow trauma
compression mostly occurs at epicondylar groove at point where nerve passes between 2 heads of flexor carpi ulnaris
mononeuropathies: ulnar nerve (C7-T1) signs
weakness/wasting of:
- medial wrist flexors
- interossei
- medial 2 lumbricals
mononeuropathies: ulnar nerve (C7-T1) treatment
rest and avoiding pressure on the nerve
night time soft elbow splinting
mononeuropathies: radial nerve (C5-T1)
nerve opens the fist
it may be damaged by compression against the humerus
mononeuropathies: radial nerve (C5-T1) signs
test for wrist and finger drop muscles involved= BEST Brachioradialis Extensor Supinator Tricep
mononeuropathies: phrenic nerve (C3-5)
consider phrenic palsy if orthopnoea (SOB while lying flat) with raised hemidiaphragm on CXR
mononeuropathies: phrenic nerve (C3-5) causes
lung cancer myeloma thymoma cervical spondylosis phrenic nucleus lesion thoracic surgery HIV muscular dystrophy
mononeuropathies: sciatic nerve (L4-S3)
damaged by pelvic tumours or fractures to pelvis or femur
lesions affect the hamstrings and all muscles below knee- foot drop
mononeuropathies: common peroneal nerve (L4-S1)
originates from sciatic nerve above the knee
often damaged as it winds around the fibular head due to trauma or sitting cross-legged
mononeuropathies: common peroneal nerve (L4-S1) signs
foot drop
weak ankle dorsiflexion
sensory loss over dorsum of foot
polyneuropathies
diffuse, symmetrical disease usually commencing peripheral
can be motor, sensory, sensorimotor and autonomic
polyneuropathies: classification
acute or chronic
sensory/motor/autonomic/mixed
demyelination, axonal degeneration or both
polyneuropathies: causes
metabolic- diabetes, renal failure, hypothyroidism
malignancy- paraneoplastic syndromes
inflammatory- guillain-barre syndrome, sarcoidosis
infections- leprosy, HIV, syphilis
polyneuropathies: sensory neuropathy presentation
numbness
affects extremities first
difficulty handling small objects
signs of trauma
polyneuropathies: motor neuropathy presentation
often rapidly progressive
weak or clumsy hands
difficulty walking and breathing
cranial nerve 3 lesions
oculomotor palsy
ptosis- dropping eyelids
fixed dilated pupil
eye down and out
cranial nerve 3 lesions: causes
raised intracranial pressure
diabetes
hypertension
giant cell arteritis
cranial nerve 6 lesions
abducens palsy
innervate lateral rectus muscle thus eyes will be adducted
cranial nerve 6 lesions: causes
MS
wernicke’s encephalopathy
pontine stroke
cranial nerves 3, 4 & 6 lesions
non functioning eye
cranial nerves 3, 4 & 6 lesions: causes
stroke
tumours
wernicke’s encephalopathy
cranial nerve 5 lesions
trigeminal palsy
jaw deviates to side of lesion
loss of corneal reflex
caused by trigeminal neuralgia, herpes zoster
cranial nerve 7 lesions
facial palsy
facial droop and weakness
cranial nerve 7 lesions: causes
bells palsy= most common lesion
fractures of petrous bones
middle ear infections
cranial nerve 8 lesions
vestibulocochlear palsy
hearing impairment
vertigo and lack of balance
cranial nerve 8 lesions: causes
skull fracture
toxic drug effects
ear infections
cranial nerves 9 & 10 lesions
glossopharyngeal and vagus palsy
gag reflex issues, swallowing issues, vocal issues
autonomic neuropathy
sympathetic and parasymp neuropathies may be isolated or part of a generalised sensorimotor peripheral neuropathy
autonomic neuropathy: causes
diabetes
guillain-barre
HIV
SLE
autonomic neuropathy: sympathetic presentation
postural hypotension- faints on standing, eating or hot bath
ejaculatory failure
reduced sweating
autonomic neuropathy: parasymp presentation
erectile dysfunction
constipation
nocturnal diarrhoea
urine retention
polyneuropathy: diagnosis
FBC, ESR, glucose, U&E, LFT, TSH, B12
CXR
urinalysis
lumbar puncture
polyneuropathy: treatment
treat the cause
foot care and shoe choice
splinting of joints
Nerve root lesion @ L2: Pain, weakness, reflex affected
pain- across upper thigh
weakness- hip flexion and adduction
reflex- N/A
Nerve root lesion @ L3: Pain, weakness, reflex affected
pain- across lower thigh
weakness- hip adduction, knee extension
reflex- knee jerk
Nerve root lesion @ L4: Pain, weakness, reflex affected
pain- across knee to medial malleolus
weakness- knee extension, foot inversion, dorisflexion
reflex- knee jerk
Nerve root lesion @ L5: Pain, weakness, reflex affected
pain- lateral shin to dorsum of foot and great toe
weakness- hip extension and abduction, knee flexion
reflex- great toe jerk
Nerve root lesion @ S1: Pain, weakness, reflex affected
pain- posterior calf to lateral foot and little toe
weakness- knee flexion, foot and toe plantar flexion
reflex- ankle jerk
focal scalp lesions
contusions
lacerations
focal skull lesions: fracture
implies considerable force
high risk of haematoma, infection and aerocele
pointed objects cause localised fractures
flat surfaces cause linear fractures
focal meninges lesions: extradural haematoma
10% of severe injuries, 15% of fatal ones
associated with skull fracture
occurs slowly over hours
focal meninges lesions: extradural haematoma causing death
brain displacement
raised intracranial pressure
herniation
infection
focal meninges lesions: subdural haematoma
usually due to tears in bridging veins- cross subdural space from superior surface of brain to midsagittal sinus
occurs slowly
focal meninges lesions: traumatic subarachnoid haematoma causes
contusions
base of skull fracture
vertebral artery dissection
intraventricular haemorrhage
focal brain lesions: contusions
superficial bruises on the brain
coup or contre coup
haemorrhagic then brown and soft for days-weeks and then indented or cavitated after months
focal brain lesions: lacerations
when contusion is sufficiently severe to teat the pia mater
focal brain lesions: haemorrhage
cerebral or cerebellar haemorrhage
superficial- due to severe contusion
deep- related to diffuse axonal injury
focal brain lesions: infection
predominantly due to skull fracture
diffuse brain lesions: diffuse axonal injury
clinicopathological syndrome of widespread axonal damage
can be caused by variety of processes
diffuse brain lesions: diffuse vascular injury
usually a result of near immediate death
multiple petechial haemorrhages throughout brain
diffuse brain lesions: hypoxia-ischaemia
often causes infarction and damage
likely in pts. with evident hypoxia, hypotension and/or raised intracranial pressure
diffuse brain lesions: swelling
occurs in 75% of pts.
causes raised intracranial pressure
diffuse brain lesions: congestive brain swelling
vasodilation and increased cerebral blood volume
diffuse brain lesions: vasogenic oedema swelling
extravasation of oedema fluid from damaged blood vessels
diffuse brain lesions: cytotoxic oedema swelling
increased water content of neurons and glia
coup vs. contre coup injuries
coup= occurs under site of impact from an object
contre coupe= occurs on side opposite area that was hit
traumatic axonal injury
focal or widespread
usually involves acceleration and deceleration of the head
mild= recovery of consciousness, variable severity of deficit
severe= unconscious from impact, can remain so or severe disability
meningitis
inflammation of the meninges
can be infective or non-infective (drugs, autoimmune)
encephalitis
inflammation of the brain
usually viral
encephalopathy
reduced level of consciousness/diffuse disease of brain substance
usually non-infective with multiple aetiologies
polyradiculopathy
inflammation of nerve roots e.g. cauda equina
myelitis
inflammation of spinal cord
meningitis: epidemiology
occurs in people of all age groups but more common in infants/elderly
meningococcal disease is notifiable to public health england
meningitis: aetiology; adults and children
neisseria meningitides- gram negative diplococci
streptococcus pneumoniae/pneumococcus
meningitis: aetiology; pregnancy/older adults
listeria monocytogenes- found in cheese so why theyre told to avoid
meningitis: aetiology; neonates
escheria coli
group b haemolytic streptococcus
meningitis: aetiology; immunocompromised
cytomegalovirus
TB
HIV
herpes simplex virus
meningitis: risk factors
intrathecal drug administration immunocompromised elderly pregnant crowding- uni students diabetes IV drug abuse
bacterial meningitis: pathophysiology
typically sudden
N. meningitides is transmitted by droplet spread
pia-arachnoid is congested with polymorphs
layer of pus forms which can form adhesions causing cranial nerve palsied and hydrocephalus
bacterial meningitis: meningococcal septicaemia pathophsyiology
bacteria invades into blood
presence of endotoxin in bacteria causes inflammatory cascade
chronic meningitis: pathophysiology
e.g. TB
brain is covered in a viscous grey-green exudate with numerous meningeal tubercles
viral meningitis: pathophysiology
predominantly lymphocytic inflammatory CSF reaction w/o pus formation
little of no cerebral oedema unless encephalitis develops
bacterial meningitis: presentation
triad= headache, neck stiffness and fever
sudden onset
intense malaise, rigor, photophobia and vomiting
irritable
seizures and CNS signs
papilloedema
bacterial meningitis: papilloedema
swelling of optic disc on fundoscopy
usually bilateral
can occur over hours to weeks
caused by raised intracranial pressure
viral meningitis: presentation
triad
benign, self limiting condition lasting 4-10 days
headache may follow for some months
chronic meningitis: presentation
mycobacterium tuberculosis
long history and vague symptoms of headache, anorexia and vomiting
signs of meningeal triad are often absent or late
meningitis: differentials
aseptic meningitis- due to tumour
sub-arachnoid haemorrhage
encephalitis
meningitis: investigations
blood culture before lumbar puncture
FBC, U&E, CRP and serum glucose
throat swab
meningitis: investigations; lumbar puncture
@L4
send for microscopy and sensitivity
can give headache, paresthesia, CSF leak and damage to spinal cord
meningitis: lumbar puncture results; TB
lymphocytes
raised protein
low/normal glucose
meningitis: lumbar puncture results; Virus
lymphocytes
normal protein
normal glucose
meningitis: lumbar puncture results; bacteria
neutrophil polymorphs
raised protein
low glucose
meningitis: investigations; CT head
exclude lesions such as tumours to do CT before lumbar puncture: - >60y/o -immunocompromised -history of CNS disease -new onset of seizures -GCS <14
meningitis: investigations; non- blanching petechial or purpuric rash
purpuric rash +signs of sepsis= meningococcal septicaemia
immediate IV benzylpenicillin or IV cefotaxime
don’t do lumbar puncture, instead of blood cultures
bacterial meningitis: treatment
if suspect bacterial- start antibiotics before tests come back
IV cefotaxime
if immunocompromised then add IV amoxicillin to cover listeria
consider steroids, dexamthasone to reduce oedema
encephalitis: epidemiology
infections are most frequent in children and elderly- mainly viral cause
more common in immunocompromised
encephalitis: viral aetiology
herpes simplex virus 1 and 2 varicella zoster epstein barr HIV mumps and measles
encephalitis: non viral aetiology
bacterial meningitis
TB
malaria
encephalitis: risk factors
extremes of age
immunocompromised
encephalitis: pathophysiology
disease which mostly affects the frontal and temporal lobes resulting in decreased consciousness, confusion and focal signs
encephalitis: general presentation
whole brain affected- problems with consciousness
can be abrupt in onset
triad= fever, headache and altered mental status
encephalitis: early presentation
begins with features of viral infection
fever, headache, myalgia, fatigue and nausea
encephalitis: progressive presentation
personality and behavioural changes decreased consciousness, confusion and drowsiness hemiparesis, dysphasia seizures coma
encephalitis: differentials
meningitis
stroke
brain tumour
encephalitis: MRI
shows area of inflammation and swelling, generally in temporal lobes in HSV
encephalitis: electroencephalography
shows periodic sharp and slow wave complexes
encephalitis: lumbar puncture
CSF shows elevated lymphocyte count
viral detection by CSF, PCR is highly sensitive for herpes simplex and varicella zoster
encephalitis: treatment
if viral then immediate treatment with anti-viral- IV aciclovir
anti seizure medication- primidone
herpes zoster
shingles
virus remains latent in sensory ganglia
caused by reactivation of varicella zoster (chicken pox) usually within the dorsal root ganglia
herpes zoster: epidemiology
90% of children exposed to chicken pox before age of 16
can affect all ages but seen in elderly
herpes zoster: aetiology
varicella zoster virus
herpes zoster: risk factors
increasing age
immunocompromised
HIV
bone marrow transplants
herpes zoster: pathophysiology
viral infection affecting peripheral nerves
when latent virus is reactivated in dorsal root ganglia it travels down the affected nerve via sensory root- dermatomal distribution
result in perineural and intramural inflammation
herpes zoster: presentation
pain and paresthesia in dermatomal distribution
malaise, myalgia, headache and fever
rash
herpes zoster: rash presentation
consists of papules and vesicles restricted to same dermatome
neuritic pain
crust formation and drying occurs over next week w/ resolution in 2-3 weeks
infectious until lesions are dried
herpes zoster: differentials
before rash:
pain in chest or abdo pain- cholecystitis or renal stones
cluster headaches or migraine
herpes zoster: diagnosis
rash is virtually diagnostic
herpes zoster: treatment
oral antiviral therapy w/i 72 hours of rash onset (aciclovir x5 daily)
topical antibiotic for secondary infection of rash
analgesia for pain
herpes zoster: post herpetic neuralgia
pain lasting more than 4 months after shingles
occurs in 10%
burning, intractable pain
responds poorly to analgesics
herpes zoster: post herpetic neuralgia treatment
tricyclic antidepressant- amitriptyline
anti-epileptic- gabapentin
anti-convulsant- carbamezapine
tetanus: pathology
inoculation through skin with clostridium tetani spores- found in soil
bacteria produce toxins such as tetanolysin- tissue destruction
tetanospasmin- clinical tetanus
tetanus: pathogenesis
tetanospasmin can travel retrogradely along axons
interferes with neurotransmitter release, increased neuron firing, unopposed muscle contraction and spams
tetanus: generalised presentation
risus sardonicus- abnormal, sustained spasm of facial muscles that appears to produce grinning
opisthotonos- spasm of muscles causing backward arching of the head, neck and spine
tetanus: localised presentation
e.g.
injury to R hand, 2 days later unopposed flexion of fingers and spasm in forearm
tetanus: prevention
better than cure
vaccinate
tetanus: symptomatic treatment
supportive- muscle relaxants, paracetamol
immunoglobulin to mop up toxin
metronidazole to clear residual bacteria
rabies: pathology
caused by rabies lyssavirus, formerly rabies virus
kills 35-50 thousand/yr
inoculation through skin with saliva of rabid animals
travels retrogradely along nerves
rabies: incubation
depends on size and site of inoculation
min 2 weeks, max 2 years
rabies: presentation
paresthesia at bite site
reaches CNS- furious or paralytic presentation
once symptomatic, invariably fatal, >99.9%
rabies: treatment
managed with sedatives
prophylaxis- PrEP (vaccination) or PEP
dementia
a syndrome caused by a number of brain disorders which cause memory loss, difficulties with thinking, problem solving or language as well as difficulties with activities of daily living
dementia: epidemiology
rare under 55 y/o
prevalence rises with age
AD more common in females than males
alzheimer’s dementia: aetiology
50%
most common cause
degeneration of cerebral cortex
accumulation of beta-amyloid peptide, a degradation product of amyloid precursor protein- results in progressive neuronal damage
vascular dementia: aetiology
25%
brain damage due to cerebrovascular disease, either major stroke, multiple smaller unrecognised strokes
presents with signs of vascular pathology
lewy-body dementia: aetiology
15%
deposition of abnormal protein with neurones in brain stem and neocortex
associated with parkinson’s
fronto-temporal dementia: aetiology
specific degeneration/atrophy of frontal and temporal lobes of the brain
behavioural and personality change, early preservation of episodic memory and spatial orientation
dementia: risk factors
family history age down's syndrome alcohol use, obesity, high BP atherosclerosis depression
alzheimer’s dementia: presentation
insidious onset with steady progression over years
short term memory loss is usually the most prominent early symptoms
slow disintegration of personality and intellect
decline in language skills
vascular dementia: presentation
stepwise deterioration with declines followed by short periods of stability
history of TIAs and/or strokes
evidence of arthropathy
dementia: presentation of Lewy bodies
fluctuating cognition with pronounced variation in attention and alertness persistent memory loss impairment in attention depression and sleep disorders visual hallucinations
dementia: differentials
substance abuse
hypothyroidism
huntington’s
dementia: investigations
mini mental state examination commonly used to screen for cognitive function
MRI to see atrophy
dementia: prevention
no specific therapy
healthy behaviour- smoking cessation, good diet, low alcohol
>6 leisure activities lowers risk
dementia: supportive care
socially active- sees friends and families
cognitively active
specialist memory service
multiple sclerosis
chronic autoimmune, T-cell mediated inflammatory disorder of the CNS in which there are multiple plaques of demyelination w/i brain and spinal cord
multiple sclerosis: epidemiology
begins early adulthood, typically 20-40 y/o
more common in females
more common in white populations
multiple sclerosis: aetiology
not understood
combination of genetics and environment
multiple sclerosis: pathophysiology
autoimmune mediated demyelination at multiple CNA sites- targeting oligodendrocytes
thought to be T cell mediated- activate B cells to produce auto-antibodies against myelin
myelin sheath regenerates but it is less efficient and when exposed to high heat conduction decreases drastically
types of multiple sclerosis: relapsing & remitting
80%- most common
symptoms occur in attacks with onset over days and typically recovery- partial or complete
periods of good health or remission are followed by sudden symptoms or relapses
types of multiple sclerosis: secondary progressive
follows from relapsing and remitting (75% of RR get secondary)
late stage that consists of gradually worsening symptoms with fewer remissions
types of multiple sclerosis: primary progressive
gradually worsening disability w/o relapses or remissions
typically presents later and is associated with fewer inflammatory changes on MRI
multiple sclerosis: presentation
usually initially monosymptomatic symptoms may worsen with heat numbness and tingling in limbs leg weakness trigeminal neuralgia constipation intension tremor amnesia sexual dysfunction
multiple sclerosis: unilateral optic neuritis presentation
pain in one eye on eye movement
reduced central vision
multiple sclerosis: brainstem demyelination presentation
diplopia, vertigo, facial numbness, dysarthria or dysphagia
clumsy/useless hand or limb due to loss of proprioception
multiple sclerosis: differentials
hereditary spastic paraplegia
cerebral variant of SLE
sarcoidosis
HIV
multiple sclerosis: investigations
requires 2+ attacks affecting different parts of CNS- 2 lesions disseminated in time and space
exclude differentials with inflammatory markers, auto-antibodies, calcium and LFTs
multiple sclerosis: MRI brain and spinal cord
diagnostic
95% have periventricular lesions
over 90% show discrete white matter abnormalities
multiple sclerosis: lumbar puncture
CSF examination shows oligoclonal IgG bands in over 90% of cases- not specific to MS
multiple sclerosis: electrophysiology investigation
visual evoked potential studies
delayed nerve conduction suggests demyelination
multiple sclerosis: acute relapse treatment
IV methylprednisolone
<3 days can shorten relapse
use steroid sparingly and aim to use less than twice a year
multiple sclerosis: treatment for frequent relapse
SC interferon 1B or 1A are anti-inflammatory cytokine and reduce relapses by 30% in active remitting MS and reduce lesion accumulation
dimethyl fumarate
monoclonal antibodies
multiple sclerosis: monoclonal antibodies
disease modifying agents
IV alemtuzumab- targets T cells
IV natalizumab- against VLA-4 receptors that allow autoimmune cells to cross BBB
multiple sclerosis: symptomatic treatment
urinary urgency/frequency- self catheterisation
incontinence- anti cholinergic alpha blocker (doxazosin)
spasticity- physio, baclofen, botox injection
epilepsy: definition
recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the brain
manifests as seizures
chronic disorder- at least 2 seizures to be diagnosed
epilepsy seizure definition
paroxysmal/unprovoked event in which changes in behaviour, sensation or cognitive are caused by excessive, hypersynchronous neuronal discharges in the brain
epilepsy: epidemiology
common
highest at extremes of age- <20 y/o or >60 y/o
can go into remission
epilepsy: aetiology
2/3rds idiopathic often familial stroke space occupying lesion- tumour alcohol withdrawal cortical scarring
epilepsy: risk factors
family history premature babies abnormal blood vessels in brain alzheimers use of drugs- cocaine stroke/tumour/infection
epilepsy: elements of a seizure
prodome
aura
post-ictally
epilepsy pathophysiology: prodome
lasting hours or days
may rarely precede the seizure
not part of seizure, results in change of mood/behaviour
epilepsy pathophysiology: aura
part of seizure
patient is aware and may precede its other manifestations
strange feeling in gut, deja vu, strange smells/lights
implies focal seizure often but not necessarily temporal lobe
epilepsy pathophysiology: post-ictally
after seizure headache confusion myalgia temporary weakness if its in motor cortex
epilepsy pathophysiology: primary generalised
simultaneous onset of electrical discharge throughout whole cortex
no localising features referable to one hemisphere
bilateral, symmetrical manifestations
loss of consciousness
epilepsy pathophysiology: partial/focal seizures
features referable to part of one hemisphere/lobe
often seen with underlying structural disease
epilepsy presentations: generalised tonic-clonic seizure
often no aura
loss of consciousness
tonic= rigid, stiff limbs, falls to floor
clonic=bilateral, rhythmic muscle jerking, seconds to minutes
eyes open and tongue often bitten
incontinence
epilepsy presentations: typical absence seizure
usually disorder of childhood
ceases activity, stares and pales for a few seconds
often don’t realise anything happened
tend to develop tonic-clonic in later life
epilepsy presentations: myoclonic seizure
sudden isolated jerk, face or trunk
patient may be thrown suddenly to ground
violently disobedient limb
epilepsy presentations: tonic seizure
sudden sustained increased tone with cries/grunts
not followed by jerking
epilepsy presentations: atonic seizure
sudden loss of muscle tone and cessation of movement
epilepsy presentations: simple partial seizure
not affecting consciousness or memory
awareness if unimpaired in motor, sensory, autonomic or psychic focal seizures
no post-ictal
epilepsy presentations: complex partial seizure
affect awareness or memory before, during or immediately after seizure
commonly arise from temporal lobe- speech, memory and emotion
post-ictal confusion
epilepsy presentations: partial seizure w/ secondary generalisation
in 2/3rds of patients with partial seizures the electrical disturbance starts focally then spreads
causes a secondary generalised seizure- usually convulsive
epilepsy presentations: temporal lobe involvement
aura 80% deja-vu auditory hallucinations funny smells anxiety out of body experience
epilepsy presentations: frontal lobe involvement
motor features such as posturing or movement of leg
Jacksonian march= seizure marches up or down motor homunculus starting in face or thumb
post-ictal Todd’s palsy= paralysis of limbs involved
epilepsy presentations: occipital lobe involvement
visual phenomena
epilepsy presentations: epilepsy rather than syncope
tongue biting head turning muscle pain loss of consciousness cyanosis post-ictally
epilepsy presentations: syncope rather than epilepsy
syncope= loss of consciousness due to hypoperfusion to the brain
epilepsy presentations: non-epileptic seizure vs. epileptic
non-epileptic= situational, longer, close mouth/eyes, do not result from sleep, no incontinence
epilepsy differential diagnosis
postural syncope cardiac arrhythmia TIA migraine panic attack non-epileptic seizure
epilepsy investigations
EEG
MRI/CT head
blood tests
genetic testing
epilepsy investigations: electroencephalogram
not diagnostic
performed to support diagnosis of epilepsy when history suggests
may help determine seizure type
epilepsy investigations: MRI
imaging hippocampus studies epilepsy
epilepsy investigations: CT head
used in emergency to look for space occupying lesion
identify or exclude structural abnormalities that could cause symptoms
epilepsy investigations: blood tests
done to rule out metabolic cause
discover comorbidities
FBC, electrolytes, Ca2+, renal function
epilepsy treatment
generally drugs are not advised after just one fit unless the risk of recurrence is high
drug resistant to drug treatment in 1/3rd of patients
epilepsy treatment: emergency measures
ensure they harm themselves as little as possible
check glucose
prolonged seizure (>3min) or repeated are treated with rectal/IV diazepam or loraezepam x2
IV phenytoin loading
epilepsy treatment: for generalised tonic-clonic seizures
oral sodium volproate- S/E =weight gain and hair loss
oral lamotrigine- S/E= maculopapular rash, blurred vision
oral carbamazepine- S/E= diplopia, rashes, impaired balance
epilepsy treatment: for absence seizure
oral sodium valproate
oral lamotrigine
oral ethosuximide
epilepsy treatment: for partial/focal seizure
carbamazepine
sodium valproate
lamotrigine
epilepsy treatment: neurosurgical
if drugs don’t work
if a single defined cause if identified such as hippocampal sclerosis or tumour
epilepsy treatment: advice to patients
must inform DVLA and cannot drive until they have been free of daytime seizures for at least one year
epilepticus
repeated seizures with brief periods of recovery can lead to epilepticus
medical emergency
risk of death if generalised tonic-clonic
epilepticus: causes
abruptly stopping anti-epileptic treatment
alcohol abuse
poor compliance to therapy
sudden unexpected death epilepsy
more common in uncontrolled epilepsy
can be related to nocturnal seizure-associated apnoea and asystole
TIA definition
transient ischaemic attack= a brief episode of neurological dysfunction due to temporary focal cerebral ischaemia w/o infarction
TIA epidemiology:
15% of first strokes are preceded by TIA
more common in males
TIA aetiology
small vessel occlusion atherothromboembolism from carotid cardioembolism from microemboli hyperviscosity hypoperfusion
TIA aetiology: cardioembolism
microemboli come from:
mural thrombus post MI or AF
valve disease
prosthetic valve
TIA aetiology: hyperviscosity
polycythaemia
sickle cell anaemia
extremely raised white cell count
myeloma
TIA aetiology: hypoperfusion
consider in younger people
cardiac dysrhythmia
postural hypotension
TIA risk factors
increased age hypertension smoking diabetes heart disease past TIA excess alcohol clotting disorder combined oral contraceptive
TIA pathophysiology
most common cause is cerebral ischaemia- lack of oxygen and nutrients to brain causes cerebral dysfunction
usually short lived so symptoms last 5-15 mins and resolves itself
TIA presentation: carotid artery
supplies frontal and medial part of cerebrum
occlusion may cause weak, contralateral symptoms of limbs
hemiparesis (weakness on entire side of body)
dysphasia
amaurosis fugax
TIA presentation: amaurosis fugax
sudden transient loss of vision in one eye
occurs due to reduction in retinal, ophthalmic or ciliary blood flow leading to temporary retinal hypoxia
TIA presentation: vertebrobasilar artery
diplopia- double vision vertigo vomiting ataxia- no control over body hemisensory loss hemianopia vision loss
stroke definition
cerebrovascular accidents
syndrome of rapid onset of neurological deficit caused by focal, cerebral, spinal or retinal infarction
stroke epidemiology
3rd most common cause of death in high income countries 11% of all deaths in UK leading cause of adult disability incidence increases with age more common in males
stroke aetiology: ischaemic
80% small vessel occlusion/thrombosis cardiac emboli from AF or infective endocarditis large artery stenosis hypoperfusion vasculitis hyperviscosity
stroke aetiology: CNS bleeds
17% trauma aneurysm rupture anticoagulation thrombolysis artery dissection subarachnoid haemorrhage
stroke aetiology: young people
vasculitis thrombophilia subarachnoid haemorrhage carotid artery dissection venous sinus thrombosis
stroke aetiology: elderly
thrombosis in situ atherothromboembolism heart emboli CNS bleed sudden drop in BP
stroke risk factors
male black or asian hypertension past TIA smoking diabetes increasing age heart disease alcohol AF hypercholesterolaemia combined contraceptive
stroke pathophysiology: ischaemic
arterial disease and atherosclerosis is main pathological process
stroke pathophysiology: cardio-embolic stroke
AF
cardiac valve disease
infective vegetations due to endocarditis
fat emboli
stroke pathophysiology: venous sinus thrombosis
very rare
thrombosis in intracranial venous sinuses
cortical infarction, seizures and raised intracranial pressure result
stroke pathophysiology: haemorrhagic
hypertension resulting in micro aneurysm rupture
cerebral amyloid angiopathy
carotid/vertebral artery dissection
stroke presentations: anterior cerebral artery
leg weakness
sensory disturbance in legs
gait apraxia
drowsiness
stroke presentations: middle cerebral artery
contralateral arm and leg weakness
contralateral sensory loss
hemianopia
aphasia- cant understand or produce speech
dysphasia- deficiency in speech generation
facial droop
stroke presentations: posterior cerebral artery
contralateral homonymous hemianopia cortical blindness visual agnosia but can see prosopagnosia- cant see faces colour naming problems
stroke presentations: vertebrobasilar artery
more catastrophic due to wide region supplied
locked in is more likely
motor deficits- hemiparesis or tetraparesis
facial paralysis
vertigo
visual disturbance
altered consciousness
stroke presentations: lacunar
small subcortical strokes
unilateral weakness of face and arm, arm and leg or all three
pure sensory loss
stroke presentations: haemorrhage or ischaemic
no reliable way to distinguish from presentation
haemorrhage is more associated with severe headache
if on anticoagulants- assume haemorrhage
stroke differentials
exclude hypoglycaemia
migraine
intracranial lesion
syncope
stroke investigations: urgent CT head
before treatment
rules out haemorrhage before starting thrombolysis
infarct is seen as low density lesion
stroke investigations: pulse, BP, ECG
look for AF
be careful treating high BP as fall in 20% can compromise cerebral perfusion
stroke investigations: bloods
look for thrombocytopenia and polycythaemia in FBC
rule out hypoglycaemia
stroke treatment: maximise reversible ischaemic tissue
ensure hydration
keep oxygen sats >95%
if ischaemia proceed to thrombolysis
stroke treatment: thrombolysis
can be given up to 4.5 hours post onset of symptoms
give tissue plasminogen activator- IV alteplase
then antiplatelet therapy- clopidogrel
if time of onset unknown and thrombolysis is unsuitable give aspirin daily for 2 weeks then lifelong clopidogrel
stroke treatment: thrombolysis contraindications
recent surgery in last 3 months recent arterial puncture history or active malignancy evidence of brain aneurysm on anticoagulants clotting disorder
treatment for haemorrhagic stroke
frequent GCS monitoring antiplatelets contraindicated reverse all anticoagulants control hypertension surgery
risk management for stroke prevention
platelet treatment- aspirin+ dipyridamole/clopidogrel
simvastatin for cholesterol
AF treatment- warfarin
ramipril for BP
TIA differentials
until full recovery- impossible to differentiate from stroke
hypoglycaemia
intracranial lesion
syncope
TIA investigations
carotid artery doppler ultrasound to look for stenosis
CT angiography to see extent of stenosis
ECG to look for MI ischaemia or AF
TIA investigations: bloods
FBC- polycythaemia ESR raised in vasculitis Glucose- hypoglycaemia creatinine cholesterol
TIA treatment: ABCD2 score risk of stroke
Age >60= 1
Blood pressure >140/90= 1
Clinical features- unilateral weakness= 2, speech disturbance w/o weakness= 1
Duration of symptoms- >1hr= 2, 10-59mins= 1
Diabetes= 1
score >6 strongly predicts a stroke and should be referred immediately
TIA treatment: antiplatelet drugs
aspirin and dipyridamole for 2 weeks, then lower dose
P2Y12 inhibitor long term- clopidogrel
anticoagulant if they have AF or mitral stenosis- warfarin
TIA treatment: control risk factors
long term statin- simvastatin
antihypertensives- ace inhibitors, ramipril or angiotensin receptor blocker, candesartan
improve diet
stop smoking
subarachnoid haemorrhage
spontaneous bleeding in subarachnoid space- between arachnoid layer of meninges and pia mater
subarachnoid haemorrhage: epidemiology
35-65 y/o
5% of strokes
subarachnoid haemorrhage causes: rupture of saccular aneurysms
80%
e.g. berry aneurysms
rupture in circle of willis @
junction of posterior communicating artery with internal carotid/ anterior communicating w/ anterior cerebral
subarachnoid haemorrhage causes: atriovenous malformation
10%
vascular development malformation often with a fistula between arterial and venous systems causing high flow through AVM
and high pressure arterialisation of draining veins
subarachnoid haemorrhage: rare causes
bleeding disorder
mycotic aneurysms
acute bacterial meningitis
tumours
subarachnoid haemorrhage: risk factors
hypertension known aneurysm family history smoking bleeding disorders
subarachnoid haemorrhage: pathophysiology
most common cause is ruptured aneurysm
leads to tissue ischaemia
rapid raised ICP as blood acts as space occupying lesion
long term pressure on brain results in deficits
subarachnoid haemorrhage: presentation
sudden, sever headache neck stiffness vomiting depressed level of consciousness coma fixed dilated pupils double vision
subarachnoid haemorrhage: differentials
must differentiate from migraine
meningitis
cortical vein thrombosis
subarachnoid haemorrhage investigations: ABG
to exclude hypoxia
subarachnoid haemorrhage investigations: heat CT
gold standard
detects >90% in first 48 hours
star shaped lesion- blood filling in gyro patterns around ventricles
subarachnoid haemorrhage investigations: lumbar puncture
if CT normal but SAH suspected
CSF is uniformly bloody early on
becomes xanthochromic (yellow) after several hours- bilirubin
subarachnoid haemorrhage: treatment
neurosurgeon referral immediately
IV fluids to keep cerebral perfusion
administer calcium blocker to reduce vasospasm and so morbidity from ischaemia
subarachnoid haemorrhage treatment: endovascular coiling
preferred to surgical clipping since has lower complication rate
promotes thrombosis and ablation of aneurysm
first line treatment where angiography shows aneurysm
subarachnoid haemorrhage treatment: surgery
intracranial stents and balloon remodelling for wide-necked aneurysms
subarachnoid haemorrhage: complications
rebleeding
cerebral ischaemia due to vasospasm
hydrocephalus due to blockage of arachnoid granulations
hyponatraemia
subdural haemorrhage
caused by accumulation of blood in subdural space
between the arachnoid and dura mater
follows rupture of a bridging vein between cortex and venous sinus
subdural haemorrhage: epidemiology
most common where patient has a small brain- alcoholics or dementia or babies
subdural haemorrhage: pathophysiology
trauma results in bleeding from bridging veins between cortex and venous sinuses
haematoma forms
weeks later it autolyses due to oncotic/osmotic pressure- water is brought into haematoma causing it to enlarge
slow rise in ICP
subdural haemorrhage: risk factors
traumatic head injury cerebral atrophy increasing age alcoholism anticoagulation
subdural haemorrhage: presentation
sleepiness
headache
unsteadiness
signs of raised ICP
subdural haemorrhage: differentials
stroke dementia CNS masses SAH extradural haemorrhage
subdural haemorrhage investigations: CT head
diffuse spreading, hyperdense crescent shaped collection of blood
usually over one hemisphere
subdural haemorrhage investigations: MRI head
for subacute haematomas and smaller haematomas
subdural haemorrhage: treatment
refer to neurosurgeons- irrigation/evacuation via burr twist drill and burr hole craniotomy
address cause of trauma
extradural haemorrhage
collection of blood between dura and bone
suspect this after head injury and conscious level falls or is slow to improve or there is a lucid interval
extradural haemorrhage: aetiology
traumatic head injury resulting in a fracture
extradural haemorrhage: risk factors
usually occurs in young adults
rare <2 y/o and >60 y/o
extradural haemorrhage: pathophysiology
mainly temporal or parietal bone
causes laceration of middle meningeal artery
blood accumulates rapidly over minutes-hours between bone and dura
extradural haemorrhage: presentation
sever headache nausea vomiting confusion decreased GCS death due resp arrest if surgical intervention not done fast enough
extradural haemorrhage presentation: lucid interval
period of time between traumatic brain injury and decrease in consciousness
whilst haematoma is still small and there is still some bleeding
can last several hours
extradural haemorrhage: differentials
epilepsy carotid dissection carbon monoxide poisoning meningitis SAH
extradural haemorrhage investigations: CT head
shows hyperdense haematoma adjacent to skull- biconvex/lense shaped/lemon shaped
extradural haemorrhage investigations: skull x ray
may be normal or show fracture lines crossing course of middle meningeal artery
extradural haemorrhage: treatment
emergency management
IV mannitol if increased ICP
neurosurgery
primary brain tumours: epidemiology
8/100,000
16th most common adult cancer
2nd most common paediatric cancer
primary brain tumours: risk factors
primary tumours more common in affluent groups ionising radiation vinyl chloride immunosuppression family history
primary brain tumours: astrocytomas
most common primary brain tumour- 85-90%
glial cell in origin
graded I-IV
primary brain tumours: grade I pilocytic astrocytomas
good prognosis
completely benign
paediatric tumour mainly
primary brain tumours: grade II diffuse astrocytoma
prognosis >5yrs
premalignant tumour
nuclear atypia
primary brain tumours: grade III anaplastic astrocytoma
prognosis 2-5 years
malignant
active growth
mitosis present
primary brain tumours: grade IV glioblastoma multiforme
<1 year
most common phenotype
active growth, mitotic activity and necrosis
very malignant
pathways to malignant gliomas: most common
mainly in those <50-60 y/o
initial genetic error is of glucose glycolysis
mutation of isocitrate dehydrogenase I
excess 2-hydroxyglutarate
triggers genetic instability in glial cells and subsequent inappropriate mitosis
pathways to malignant gliomas: less common
more common in those >50-60 y/o
no IDH-1 mutation
catastrophic genetic mutation
poor prognosis even for low grade
primary brain tumours: oligodendroma
most common in 40-50y/o arise from oligodendrocytes grow slowly over several years calcification is common may have seizures WHO grade II all have IDH-1 mutation
primary brain tumours: ependymomas
arise from ependymal cells
line ventricles and spinal cord
primary brain tumours: meningiomas
more common in older people and women
benign and arise from arachnoid mater and may grow to a large size
primary brain tumours: neurofibromas/schwanomas
solid, benign tumours that arise from schwann cells
occur principally in cerebellopontine angle
primary brain tumours: medulloblastoma
WHO grade IV primitive small blue cell tumour of cerebellum in childhood highly malignant but can respond to excision and chemo
primary brain tumours: presentation (4 cardinal symptoms)
symptoms of raised ICP
progressive neurological deficit
epilepsy/seizures
lethargy
primary brain tumours presentation: raised ICP
progressive headache
drowsiness
vomiting
papilloedema
primary brain tumours presentation: raised ICP- papilloedema
swelling of optic disc due to obstruction of venous return from retina loss of crisp optic nerve head margins venous engorgement retinal oedema haemorrhages
primary brain tumours presentation: progressive neurological deficit
depends on region affected temporal=dysphagia.amnesia frontal=hemiparesis/personality change/unable to make plans parietal= hemisensory loss/dysphagia occipital=contralateral visual defects cerebellum=DASHING
primary brain tumours presentation: progressive neurological deficit (DASHING)
Dysdiaochokinesis Ataxia Slurred speech Hypotonia Intention tremor Nystagmus Gait abnormality
primary brain tumours presentation: epilepsy/seizure
sinister when of recent onset
primary brain tumours: differentials
other causes of space occupying lesions
aneurysm, abscess, cyst, haemorrhage, idiopathic intracranial hypertension
primary brain tumours investigations: CT/MRI
determine size and location of lesion
high grade have irregular edges and high growth rates
primary brain tumours investigations: biopsy
via skull burr hole
determines cancer grade
primary brain tumours investigations: lumbar puncture
contraindicated when any possibility of a mass lesion- withdrawing CSF may provoke immediate coning
results in brainstem compression as it passes through foramen magnum
primary brain tumours: treatment
surgery to remove mass whenever possible
chemo
oral dexamethasone
anticonvulsants for seizures- oral carbamazepine
primary brain tumours treatment: chemotherapy for glioma
at same time as surgery and then for 6 weeks post op
e.g. temozolomide
primary brain tumours treatment: oral dexamethasone
most powerful synthetic steroid
rapidly improves brain performance
reduces inflammation and oedema
secondary brain tumours: common neoplasms to metastasise to CNS
10x more common than primary non small cell lung cancer small cell lung cancer breast cancer melanoma GI renal cell
secondary brain tumours: treatment
surgery if <75 y/o
radiotherapy
chemo
palliative care
pathology of raised intracranial pressure
herniation haemorrhage
tonsillar herniation/coning
local deformity
decreased CSF volume
cerebellar disease: ataxia
name given to a group of neurological disorders that affect balance, coordination and speech
cerebellar disease: signs and symptoms
dysarthria- slurring of speech dysphagia- difficulty swallowing clumsiness intention tremor unsteadiness stumbling/falls nystagmus limb and gait ataxia
cerebellar disease: classification of ataxia
congenital ataxia
episodic ataxia- attacks, resolves, reoccurs
autosomal recessive/dominant
sporadic
cerebellar disease: autosomal recessive ataxia
ataxia of gait and limb
absent reflectors
complications include diabetes and cardiomyopathy
cerebellar disease: autosomal dominant ataxia
most common in UK
slowly progressive with dysarthria, dysphagia and gait ataxia
stats from late 40s-early 50s
cerebellar disease: sporadic ataxia
gluten ataxia
toxic effects
cerebellar disease: investigations
cerebrovascular damage
primary tumours
secondary tumours hydrocephalus
MS
neurological disorders and psychiatric presentations
cognitive, psychological and behavioural sequelae of CNS disorder depend on:
- tempo of underlying disorder
- site of brain affected
- neurotransmitter system involved
- individual characteristics
neurological disorders and psychiatric presentations: tempo
acute= trauma, drugs and infections. associated with delirium or confusional state chronic= dementia
neurological disorders and psychiatric presentations: site
certain brain regions are associated with particular patterns of psychological and behavioural disturbances
e.g. right hemisphere stroke can give rise to mania
neurological disorders and psychiatric presentations: neurotransmitter
memory impairment in alzheimers= acetyl choline depletion
depression in parkinsons= serotonin, noradrenaline and dopamine depletion
neurological disorders and psychiatric presentations: individual characteristics
age, gender, education or prior psychiatric history can affect how brain pathology can give rise to symptoms.
e.g. higher levels of education can protect against alzheimer’s
inherited neurological disorders: Wilson’s disease
disorder of hepatic copper disposition
presents with personality change, mood disturbance, psychosis and cognitive impairment
inherited neurological disorders: acute intermittent porphyria
metabolic disorder of haem
can give rise to acute psychosis, agitation, mania and depression
inherited neurological disorders: neuroacanthocytosis
blood contains misshapen red blood cells
associated with anxiety, paranoia, depression, obsessive behaviour
presentation of inherited neurological disorders: huntington’s
subcortical dementia anxiety depression personality changes delusions apathy suicidal thoughts
presentation of acquired neurological disorders: fronto-temporal dementia
blunting of emotions anxiety egocentricity compulsive behaviour neglect of personal appearance
presentation of acquired neurological disorders: left lobe dysfunction
presents with semantic dementia
progressive word finding difficulty
loss of language comprehension
depletion of conceptual knowledge
presentation of acquired neurological disorders: right lobe dysfunction
prosopagnosia- impaired face recognition
loss of knowledge about people
presentation of acquired neurological disorders: vascular
confusional states occur in 1/3 of pts. in acute stroke
focal behavioural disturbance caused by cerebral ischaemia can mimic functional disorder
presentation of acquired neurological disorders: MS
fatigue
depression
mania
psychosis
presentation of acquired neurological disorders: HIV associated dementia
apathy
social withdrawal
presentation of acquired neurological disorders: variant creutzfeldt-jakob disease
anxiety or depression
cognitive symptoms develop
varied neurological features including pyramidal, extrapyramidal, cerebellar signs and myoclonus
presentation of acquired neurological disorders: hypothyroidism
lethargy impaired cognition hallucinations delusions often paranoid
presentation of acquired neurological disorders: hyperthyroidism
anxiety
irritability
delirium
psychosis
presentation of acquired neurological disorders: pheochromocytoma
chronic anxiety
paroxysmal dear akin to panic
presentation of acquired neurological disorders: neoplastic/paraneoplastic
depression
paranoia
confusion
disorientation
presentation of acquired neurological disorders: trauma
delirium
insidious cognitive decline
odd behaviour
presentation of acquired neurological disorders: Wernicke’s encephalopathy
confusion
ataxia
ophthalmoplegia
presentation of acquired neurological disorders: vitamin B12 deficiency
cognitive decline
organic psychosis
somatisation disorders
when physical symptoms are caused by mental or emotional factors
mental or emotional problem is expressed as one or more physical symptom
somatisation disorders: somatisation
many physical symptoms from different parts of the body
somatisation disorders: hypochondriasis
fear that the minor symptoms may be due to a serious disease
somatisation disorders: conversion disorder
a person has symptoms which suggest a serious disease of the brain or nerves such as total loss of vision
they develop quickly in response to stress
somatisation disorders: body dysmorphia
a person spends a lot of time worried and concerned about their appearance, focussing on an apparent physical defect that others cannot see
somatisation disorders: pain disorder
a person has persistent pain that cannot be attributed to a physical disorder
dissociative disorders
a range of conditions that can cause physical or psychological problems
can be short lived, following trauma, and resolve on their own
can last a long time
dissociative disorders: of movement or sensation
includes convulsions
paralysis
and loss of sensation
dissociative disorders: dissociative amnesia
periods where they cannot remember information about themselves
may forget a learnt skill
dissociative disorders: identity disorder
may feel uncertain about their identity and who they are
may feel presence of other identities
spinal cord disease: hemiplegia
paralysis of one side of the body caused by lesion of brain
spinal cord disease: paraplegia
paralysis of both legs
always caused by spinal cord lesion
spinal cord disease: upper motor neurone signs
contralateral to lesion
indicate lesion above anterior horn cell
increased muscle tone
spinal cord disease: lower motor neurone signs
ipsilateral to lesion
indicate lesion is either in anterior horn cell or distal to anterior horn cell
decreased muscle tone
spinal cord disease: spondylolisthesis
slippage of one vertebra over the one below
nerve root comes out above the disc
therefore root affected will be one below disc herniation
spinal cord disease: spondylosis
degenerative disc disease
spinal cord disease: myelopathy
caused by spinal cord compression
upper motor neurone signs
spinal cord disease: radiculopathy
caused by spinal root compression
lower motor neurone signs
pain down dermatome
weakness in myotome
spinal cord compression
compression of spinal cord resulting in upper motor neurone signs and specific symptoms dependent on the location of compression
spinal cord compression causes: vertebral body neoplasms
most common cause of acute compression
secondary malignancy commonly from lung, breast, prostate, myeloma or lymphoma
spinal cord compression causes: disc herniation
when centre of disc (nucleus pulposus) has moved through annulus resulting in pressure on nerve root and pain
spinal cord compression causes: disc prolapse
when nucleus pulposus moves and presses against the annulus but it doesn’t escape outside annulus
can produce a bulge in disc- this results in pressure on nerve causing pain
spinal cord compression causes: rare
infection- epidural abscess
haematoma- warfarin
primary spinral cord tumour
spinal cord compression presentation: sensory loss below level of lesion
known as the sensory level
sensation abruptly diminishes 1/2 cord segments below the level of actual anatomical lesion
spinal cord compression presentation: L5/S1
S1 nerve root compression= sciatica
sensory loss/pain in back of thigh/leg/lateral aspect of little toe
spinal cord compression presentation: L4/L5
sensory loss/pain in lateral thigh/leg and medial side of big toe
spinal cord compression: differentials
transverse myelitis multiple sclerosis cord vasculitis trauma dissecting aneurysm
spinal cord compression: MRI
do not delay imaging
identifies the cause and site of compression
spinal cord compression: treatment
refer to neurosurgeons
epidural steroid injection
surgical decompression
removal of herniated tissue
cauda equine syndrome
medical emergency
spinal damage at or caudal to L1
cauda equine syndrome: epidemiology
rare
occurs mainly in adults
cauda equine syndrome: aetiology
common cause is lumbar disc herniation @ L4/5 or L5/S1 tumours trauma infection spondylolisthesis
cauda equine syndrome: presentation
bilateral sciatica saddle anaesthesia bladder/bowel dysfunction erectile dysfunction variable leg weakness- flaccid and areflexic
cauda equine syndrome: differentials
conus medullaris syndrome
vertebral fracture
peripheral neuropathy
cauda equine syndrome: investigations
MRI to localise lesion
knee flexion test
ankle plantar flexion test
cauda equine syndrome: treatment
refer to neurosurgeon asap to relieve pressure
parkinson’s disease
degenerative movement disorder caused by a reduction in dopamine in substantia nigra
parkinson’s: epidemiology
increasing prevalence with age
more common in males
peak onset 55-65 y/o
non smokers have higher risk
parkinson’s: aetiology
idiopathic drug induced environmental factors parkinson genes oxidative stress and mitochondrial dysfunction
parkinson’s: pathophysiology
- substantia nigra usually produces dopamine
- mitochondrial dysfunction results in progressive degeneration of dopaminergic neurones that project into striatum of basal ganglia
- less dopamine means thalamus is inhibited
- a decrease in movement (hence symptoms)
parkinson’s: presentation
onset is usually gradual impaired dexterity unilateral foot drop asymmetrical- one side worse than the others difficulty with fine movements speech quiet drooling of saliva depression is common
parkinson’s presentation: triad
tremor
rigidity
bradykinesia
parkinson’s presentation: tremor
worse at rest often asymmetrical obvious in hands improved by voluntary movements made worse by anxiety
parkinson’s presentation: rigidity
as extrapyramidal lesion
increased tone in limbs and trunk
resist passive extension throughout movement
can cause pain
parkinson’s presentation: bradykinesia/hypokinesia
slow to initiate movement and slow, low-amplitude excursions in repetitive actions
reduced blink rate, monotonous hypophonic speech, write smaller
parkinson’s presentation: gait
reduced asymmetrical arm swing narrow gait stooped postured small steps shuffling steps, dragging feet expressionless face
parkinson’s: differentials
benign essential tremor multiple cerebral infarct lewy-body dementia drug-induced, trauma if suspect early parkinson's but: dementia, incontinence, symmetry, early falls. THEN probably not parkinson's
parkinson’s: investigations
clinical diagnosis
confirm with response to L-DOPA
parkinson’s: treatment
aim is compensate for loss of dopamine
physiotherapy for balance, speech and gait problems
parkinson’s treatment: L-DOPA
gold standar
give alongside decarboxylase inhibitor (co-careldopa) (prevents peripheral conversion of LDOPA, reducing peripheral side effects and maximises dose that crosses BBB)
precursor to dopamine so can cross BBB
parkinson’s L-DOPA: side effects
nausea vomiting arrhythmia psychosis motor complications
parkinson’s L-DOPA side effects: reduced efficacy
effect wears off in 5-10 years
so L-DOPA avoided for as long as possible
parkinson’s L-DOPA side effects: on-dyskinesias
hyperkinetic, choreiform movement when drug works
repetitive, rapid, jerky, well coordinated, involuntary
parkinson’s L-DOPA side effects: off-dyskinesias
fixed, painful, dystonic posturing
twisting
caused by sustained repetitive muscle contractions
parkinson’s L-DOPA side effects: freezing
unpredictable loss of mobility
parkinson’s treatment: dopamine agonists
oral ropinrole
used to delay starting L-DOPA
parkinson’s treatment: monoamine oxidase B inhibitors
oral selegiline
inhibit MAO-B which break down dopamine- so dopamine remains for longer
used to delay starting L-DOPA
parkinson’s treatment: catechol-O-methyl transferase inhibitors
oral entacapone
inhibition stops breakdown of dopamine
parkinson’s treatment: neuropsychiatric complications
depression, dementia, psychosis
SSRI’s- citalopram
antipsychotics- quetiapine
huntington’s chorea
huntington’s is a cause of chorea and is a neurodegenerative disorder
lack of inhibitory neurotransmitter GABA
huntington’s chorea: epidemiology
autosomal dominant condition with full penetrance
presents middle age
huntington’s chorea: aetiology
mutation on chromosome 4
results in repeated expression of CAG sequence
huntington’s chorea: risk factors
having a parent with Huntington’s
child has 50% risk of getting it
huntington’s chorea: pathophysiology
repeated CAG leads to translation of expanded polyglutamine repeat sequence
the more CAG is repeated the earlier the onset
progressive cerebral atrophy with marked loss of neurones in caudate nucleus and putamen
specific loss of GABA-nergic and cholinergic neurons
huntington’s chorea: presentation
mild psychotic and behavioural symptoms dysarthria, dysphagia and abnormal eye movements apathy dementia seizures chorea
huntington’s chorea: chorea presentation
relentlessly progressive, jerky, explosive, rigidity involuntary movements ceases when sleeping can't sit still may begin as general restlessness
huntington’s chorea: differentials
sydenham’s chorea
wilson’s disease
SLE
stroke of basal ganglia
huntington’s chorea: genetic testing
shows how many CAG repeats
counselling required due to impact of positive diagnosis
huntington’s chorea: CT/MRI
shows caudate nucleus atrophy and increased size of frontal horns of lateral ventricles
huntington’s chorea: treatment
no treatment to prevent progression
counselling
antidepressants
risperidone treats aggression
huntington’s chorea: symptomatic management of chorea
benzodiazepines
sulpiride- neuroepileptic
tetrabenazine- dopamine depleting agent
myasthenia gravis
autoimmune disease against nicotinic acetylcholine receptors (AChR) in neuromuscular junction
myasthenia gravis: epidemiology
more common in females than males UNTIL over 50 is more common in males
peak age of incidence for women = 30 y/o, males = 60 y/o
myasthenia gravis: aetiology/risk factors
in women, associated with other autoimmune disease and thymic hyperplasia
in men it is associated with thymic atrophy or thymic tumour
myasthenia gravis: pathophysiology
autoimmune
mediated by antibodies to AChR- interfere with neuromuscular junction via depletion of working post-synaptic sites
achieved by immune complex deposition of anti-AChR IgG and complement at post-synaptic membranes
both T and B cells implicated
blocked excitatory effect- muscle weakness
myasthenia gravis: presentation
proximal limb muscles, speech and facial expression are commonly affected
ptosis, diplopia and myasthenic snarl on smiling
resp difficulties
myasthenia gravis presentation: muscle groups affected
in order:
- extra-ocular
- bulbar (swallowing/chewing)
- face
- neck
- trunk
myasthenia gravis presentation: increasing muscular fatigue
worsened by pregnancy, infection, exercise
to elicit:
-ask to count to 50, their voice becomes less audible
-hold your finger up high, ask to keep looking at it with eyes only, can’t keep it up
myasthenia gravis: differentials
MS
hyperthyroidism
acute guillain-barre syndrome
lambart-eaton myasthenic syndrom
myasthenia gravis investigations: serum anti-AChR
raised in 90%
if negative then look for muscle specific tyrosine kinase antibodies (anti-MuSK)
myasthenia gravis investigations: electromyography and nerve conduction study
EMG detects it as muscle cells not properly activated
characteristic decrement occurs in evoked muscle action potential during repetitive stimulation
myasthenia gravis investigations: CT of thymus
look for hyperplasia/ atrophy/ tumour
myasthenia gravis investigations: tensilon test
IV edrophonium given
muscle power increases within seconds
rarely used due to side effects
myasthenia gravis treatment: symptom control
anti-cholinesterase - pyridostigmine
so more ACh remains in neuromuscular junction
myasthenia gravis treatment: immunosuppression
prednisolone
treat relapse or if there’s no response to pyridostigmine
myasthenia gravis treatment: thymectomy
removal of thymus if onset < 50 y/o and disease not controlled with anti-cholinesterase
myasthenia gravis treatment: myasthenic crisis
weakness of the resp muscles during a relapse can be life threatening
monitor FVC
treat with plasmapheresis
paresis
impaired ability to move a body part in response to will
paralysis
ability to move a body part in response to will is completely lost
ataxia
willed movements are clumsy, ill-directional or uncontrolled
involuntary movements
spontaneous movement of a body part, independently of will
apraxia
disorder of consciously organised pattern of movement or impaired ability to recall acquired motor skills
potential sites of damage along motor pathway
motor nuclei of cranial nerve motor neurones in spinal cord spinal ventral roots peripheral nerves neuromuscular junction muscle
upper motor neurone signs
upper- everything goes up! increased muscle tone brisk reflexes plantars are upturned on stimulation upper limb extensor muscles weaker than flexor lower limb=opposite
lower motor neurone signs
lower- everything goes down! muscle tone reduced muscle wasting fasciculation reflexes depressed
motor neurone disease
cluster of major degenerative diseases characterised by selective loss of neurones in motor cortex
cranial nerve nuclei and anterior horn cells
motor neurone disease: epidemiology
more common in males
median age of onset 60 y/o
often fatal in 2-4 years
motor neurone disease: aetiology/risk factors
no established risk factors
5-10% familial- mutation in free radical scavenging enzyme (SOD-1)
motor neurone disease: pathophysiology
degenerative condition affecting motor neurones-anterior horn cells
cause both UMN and LMN dysfunction but no sensory or sphincter disturbance, never affects movements
motor neurone disease presentation: amyotrophic lateral sclerosis
UMN and LMN most common loss in motor cortex and anterior horn of the cord split hand sign cramps common wrist and foot drop
motor neurone disease presentation: progressive muscular atrophy
LMN only
present with weakness, wasting and fasciculation
distal muscle before proximal
motor neurone disease presentation: progressive bulbar pasty
LMN only
lower cranial nerves and nuclei initially
dysarthria, dysphasia, nasal regurgitation of fluids
LMN lesion of tongue
motor neurone disease presentation: primary lateral sclerosis
UMN only
least common
loss of Betz cells in motor cortex
no cognitive decline
motor neurone disease: differentials
MS polyneuropathies myasthenia gravis diabetic amotrophy guillain-barre spinal cord tumours
motor neurone disease investigations: clinical findings
definite: LMN+UMN signs in 3 regions
probable: UMN+LMN in 2 regions
probable: LMN+UMN in 1 region/UMN in more than 1 region… w/ EMG showing acute denervation in >2 limbs
possible: LMN+UMN in 1 region
motor neurone disease investigations: brain/cord MRI
helps exclude structural causes
motor neurone disease investigations: lumbar puncture
exclude inflammatory causes
motor neurone disease investigations: nerve conduction studies
denervation of muscles due to degenerative of LMN confirmed by EMG
motor neurone disease treatment: anti-glutamatergic drugs
oral riluzole
sodium channel blocker that inhibits glutamate release
prolongs life by 3 months
but raises LFTs
motor neurone disease treatment: drooling
drooling due to bulbar palsy
oral propantheline or amitriptyline
motor neurone disease treatment: dysphagia
blend food
nasogastric tube
percutaneous catheter gastrostomy
motor neurone disease treatment: spasms
oral baclofen
guillain-barre syndrome
acute inflammatory demyelinating ascending polyneuropathy
affects peripheral nervous system- schwann cells
follows upper resp tract or GI infection
guillain-barre syndrome: epidemiology
more common in males
peak ages= 15-35 y/o and 50-75 y/o
most common acute polyneuropathy
guillain-barre syndrome: aetiology
campylobacter jejuni cytomegalovirus mycoplasma zoster HIV epstein-barr virus
guillain-barre syndrome: risk factors
history of resp/GI infection 1-3 weeks prior to onset
vaccinations have been implicated
guillain-barre syndrome: pathophysiology
infectious organisms share same antigens as those on schwann cells- leads to autoantibody mediated nerve cell damage
reduction in peripheral nerve conduction follows- acute polyneuropathy
guillain-barre syndrome: presentation
- 1-3 weeks post infection, symmetrical ascending muscle weakness
- all limbs then affected, can lead to paralysis
- proximal muscles are more affected- trunk/resp/CN 7
- pain common
guillain-barre syndrome: differentials
other causes of acute paralysis:
- hypokalaemia
- stroke
- brainstem compression
- encephalitis
- vasculitis
- myasthenia gravis
guillain-barre syndrome: nerve conduction studies
diagnostic if matches clinical examination
show slowing of conduction, prolonged distal motor latency
guillain-barre syndrome: lumbar puncture
done at L4
CSF has raised protein but normal white cell count
guillain-barre syndrome: spirometry
monitors FVC if resp involvement
decreased FVC indicates the need to admit to ITU
guillain-barre syndrome: treatment
ventilate to improve FVC
IV immunoglobulin for 5 days- decreases severity of paralysis
plasma exchange
low molecular weight heparin and compression stockings
headache
a symptom of many different illnesses and medications
headache classification
primary secondary and other (trigeminal neuralgia/facial pain)
primary headaches
no underlying cause
migraine, cluster and tension
secondary headaches
underlying cause
meningitis, SAH, giant cell arteritis, medication
secondary headache red flags
HIV or immunosuppressed fever thunderclap seizure suspected meningitis/encephalitis
migraines
recurrent throbbing headache often preceded by an aura and associated with vomiting and visual changes
migraines: epidemiology
most common cause of episodic/recurrent headache
more common in females
90% onset before 40 y/o
migraines: causes CHOCOLATE
Chocolate Hangovers Orgasms Cheese Oral contraception Lie-ins Alcohol Tumult (loud noise) Exercise
migraines: risk factors
females
adolescence
genetic component- family history
migraines: pathophysiology
- genetics play a role in causing neuronal-hyper-excitability
- changes in brainstem blood flow lead to an unstable trigeminal nerve nucleus in basal thalamus
- self propagating wave spread across cerebral cortex
- release of inflammatory mediators which act on trigeminal nerve nucleus
migraines without aura: presentation
attacks for 4-72 hours at least 2 of: unilateral/pulsing/moderate-severe pain/aggravated by physical activity during, at least one of: nausea/vomiting/photophobia
migraines with auras: presentation
at least 2 attacks
aura precedes attack by minutes
visual= chaotic cascading/jumbling/distorting lines/dots. Black hole in field. hemianopia
tingling/prickling face
general migraines: features
at least 2 of:
unilateral pain/throbbing pain/moderate-severe/motion sensitivity
at least 1 of:
nausea/vomiting/photophobia
migraines: differentials
tension headache
medication
brain tumour
migraines: investigations
mainly clinical
examine eyes for papilloedema, BP, head and neck
migraines: when to perform neuroimaging
worst headache/thunderclap change in pattern abnormal neuro exam onset > 50 y/o epilepsy
migraines: lumbar puncture investigations
worst headache/thunderclap
rapid onset/progressive
neuroimaging should precede to rule out mass/lesion/raised ICP
migraines: acute treatment
NSAIDs- avoid ibuprofen
triptans- sumatriptan
migraines: prevention
if more than 2 attacks/month or acute treatment needed 2x/week
beta blocker- propranolol
amitriptyline
tension headaches
most chronic daily and recurrent headaches are tension headaches
tension headaches: epidemiology
can be episodic, <15 days/month
or chronic >15/month
tension headaches: aetiology
stress sleep deprivation hunger eyestrain anxiety noise
tension headaches: presentation
without vomiting not affected by exercise tight band sensation pressure behind eyes 30 mins-7 days
tension headaches: pain presentation
bilateral
pressing/tight non-pulsatile
mild/moderate intensity
scalp muscle tenderness
tension headaches: differentials
migraine
cluster headache
giant cell arteritis
drug induced
tension headaches: investigations
clinical diagnosis from history
tension headaches: symptomatic treatment
aspirin paracetamol NSAIDs no opioids amitriptyline
cluster headaches
most disabling headache disorders
cluster headaches: epidemiology
rare 1/1000
more common in males
affects adults, 20-40 y/o
common in smokers
cluster headaches: risk factors
smoker
male
autosomal dominant gene has a role
cluster headaches: pathophysiology
unknown
may be due to superficial temporal artery smooth muscle, hyper-activity to serotonin
cluster headaches: presentation
abrupt onset
excruciating pain around one eye/temple/forehead
facial flushing
miosis/ptosis
pain is strictly unilateral and almost always affects same side
last 4-12 weeks
cluster headaches: differentials
migraine
cluster headaches: investigations
clinical diagnosis
at least 5 headaches fulfilling typical presentation
cluster headaches: treatment
analgesics unhelpful
triptan- SC sumatriptan. reduce vascular inflammation
cluster headaches: presentation
calcium channel blocker- verapamil
avoid alcohol
corticosteroids may help- prednisolone
trigeminal neuralgia
CN5= motor and sensory .1=ophthalmic .2= maxillary .3=mandibular chronic debilitating condition resulting in intense and extreme episodes of pain
trigeminal neuralgia: epidemiology
peak incidence 50-60 y/o
more common in females
trigeminal neuralgia: aetiology
mainly due to compression of trigeminal nerve by a loop of vein or artery
local pathology= aneurysms, meningeal inflammation, tumours
trigeminal neuralgia: fifth nerve lesion causes
w/i brainstem= tumour, MS, infarction
cerebellopontine angle= acoustic neuroma, tumour
petrous bone=spreading middle ear infection
cavernous sinus= aneurysm of internal carotid
trigeminal neuralgia: pathophysiology
hypertension
triggered by washing affected area/shaving/eating/talking
trigeminal neuralgia: presentation
compression of the trigeminal nerve results in demyelination and excitation of the nerve resulting in erratic pain signalling
trigeminal neuralgia: pain presentation
almost always unilateral 3 attacks required reoccurring in paroxysmal attacks from seconds to minutes severe intensity electric shock like precipitated by innocuous stimuli
trigeminal neuralgia: differentials
giant cell arteritis/temporal arteritis should be excluded dental pathology temporomandibular joint dysfunction migraine cluster
trigeminal neuralgia: investigations
need 3 attacks with unilateral face pain
based on history
MRI to exclude secondary causes
