neuro Flashcards
what is superiorly at the brainstem
thalamus n internal capsule
what is inferiorly at the brainstem
spinal cord
what are descending motor tracts
pyramidal tracts
what are ascending sensory tracts
lemnisci
what are some tumours affecting brainstem?
meningioma
schwannoma
astrocytoma
metastasis
what is an inflammatory disorder affecting brainstem
MS
what is criteria for brainstem death?
pupils corneal reflex cough reflex gag reflex respirations response to pain
what does peripheral neuropathy refer to?
any disorder of the PNS
what is diff btwn acute and chronic neuropathies?
acute - evolve rapidly, severe enough to make pt seek A&E help
chronic - outpatient setting, can be further classified based on pathology and neurophysiological findings
which are the large myelinated fibres?
a alpha (proprioception)
a beta (light touch, pressure and vibration)
which re the small fibres?
a alpha (myelinated) c (unmyelinated)
both transmit signals regarding pain
also a alpha - cold sensation
c - warm sensation
what is mononeuropathy
problem w/ 1 nerve
what is polyneuropathy
problem w/ many nerves
name some common mononeuropathies
carpal tunnel syndrome (median nerve)
ulnar neuropathy (entrapment at cubital tunnel)
peroneal neuropathy (entrapment at fibular head)
what is ataxia?
poor balance
sensory (loss of proprioception) or cerebellar
when sensory, ataxia gets worse w/ eyes closed or when dark
how do peripheral neuropathies present differently?
symmetrical (sensorimotor)
asymmetrical (sensory)
asymmetrical (sensorimotor)
how do symmetrical peripheral neuropathies present?
initially sensory, but eventually sensorimotor
commonest type
how does asymmetrical peripheral neuropathies present?
patchy distribution of symptoms
dorsal root ganglia affected
uncommon - paraneoplastic, sjogre, gluten sensitivity
how do asymmetrical sensorimotor peripheral neuropathies present?
mononeuritis multiplex
very uncommon
painful
how do u clinically examine peripheral neuropathies?
reduced/absent tendon reflexes
sensory deficit
weakness - muscle trophies
what is axonal peripheral neuropathy associated with?
systemic disease
what does chronic mean?
develops over at least 6m
what does idiopathic mean?
no aetiology can be identified despite extensive investigations
how do u treat chronic neuropathies?
symptomatic treatment
aim to stop disease progression
what are the 3 main branches of the aortic arch?
brachiocephalic (R CC & R sub)
L common carotid
L subclavian
where does the R CCA arise from?
brachiocephalic artery
where does the L CCA arise from??
aortic arch
does the CCA have any branches? where do they bifurcate?
no - C3-4
what do the CCA split into?
internal and external carotid arteries (At upper border of thyroid cartilage)
where is a typical area to see carotid artery dissection?
carotid canal - vulnerability of anatomical dissection bc of
what are the 4 “parts” of the internal carotid artery?
cervical
petrous
cavernous
supraclinoid (intradural)
what do the sup hypophyseal arteries supply?
pit gland/stalk
hypothalamus
optic chiasm
what does the anterior choroidal artery supply?
choroid plexus optic tract cerebral peduncle internal capsule medial temporal lobe
look at territories supplied by MCA/ACA/PCA
!
middle - outer bits on both sides
anterior - where 2 hemispheres connect
posterior - back of head, post lobe
what are the 2 types of head injury?
non-missile - BLUNT (most common)
missile - PENETRATING (penetration of skull/brain)
how can lesions be distributed?
focal
diffuse brain lesions
what is primary vs secondary time course of trauma?
primary - immediate biophysical forces of trauma
secondary - presenting some time after traumatic event
what is some focal damage in diff areas after non-missile (blunt) trauma
(scalp, skull, meninges, brain)
scalp - lacerations
skull - fracture
meninges - haemorrhage, infections
brain - confusions, infection etc
what is some diffuse brain lesion damage ???? after non missile/blunt trauma
diffuse axonal/vascular injury
hypoxia-ischaemia
swelling
what does skull fracture imply? (4)
considerable force
incr risk of haematoma/infection/aerocele
angled/pointed objects - localised fractures, open/depressed
flat surfaces - linear fractures, can extend to skull base
what is sig abt fracture lines?
1 fracture line will not cross any other fracture lines … can deduce order from this
what are extradural haematomas like ? (3)
cause? time frame? how can they cause death?
skull fracture
occurs slowly over hrs
can cause death by: brain displacement, herniation, raised ICP
what are extradural haematomas?
what are they usually associated with?
collection of blood that forms between the inner surface of the skull and outer layer of the dura (endosteal layer).
usually associated with a history of head trauma and frequently associated skull fracture.
what are subdural haematomas like ? (4)
why do they happen?
what is the onset?
what are they usually surrounded by?
what can they cause?
(underneath dura mater)
usually due to tears in bridging veins
can occur slowly (‘chronic’) in shrunken (old, alcoholic?) brains as well as acutely
usually surrounded by membrane of granulation tissue
cause of cog decline in elderly ! treatable
what are some causes of a traumatic subarachnoid haematoma?
punch in the neck - rupture of vertebral artery
laceration
base of skull fracture
IV haemorrhage
what is diff btwn superficial and deep cerebral/bellar haemorrhage
superficial: due tos evere contusion (bruise)
deep: related to diffuse axonal injury
what is a contusion?
bruise
what is a risk for any head injuries in A&E?
meningitis
what is a neuro laceration?
when contusion sufficient enough to tear in layer of brain (pia mater)
what is diff btwn coup contusion and contre coup?
coup = at site of impact
contre coup = away from site of impact
what is mild traumatic axonal injury?
hurt ur head, have recovery of consciousness ± LT, variable severity deficit
what is severe traumatic axonal injury?
hurt ur head, become unconscious from impact & remain so or severe disability
what does brain swelling lead to?
increased ICP
name 2 causes of brain herniation
bleeding
brain swelling
hypoxia-ischaemia is likely in which patients who’ve had? (3)
- clinically evident hypoxia
- hypotension w systolic BP <80mmHg for ≥15mins
- raised ICP
what is 1 of the LT consequences of head injuries?
chronic traumatic encephalopathy eg Muhammad Ali
what happens in chronic traumatic encephalopathy?
repetitive mild traumatic brain injury
initially irritability, aggression, depression, memory loss
then dementia, gait/speech issues, parkinsonism
some have MND-like symptoms
what are some infective causes of meningitis?
bacterial
viral
fungal parasitic
what is the first line of treatment usually before diagnosis of meningitis?
antimicrobials
the syndrome of meningitis must be administered from what?
brain abscesses and encephalitis, other major CNS syndromes
what is meningitis?
inflammation of meninges (Pia mater, arachnoid, dura)
what are some non-infective causes of meningitis?
paraneoplastic
drug side effects
auto immune eg vasculitis/SLE
how does brain infection get in?
neurosurgical complications eg post op, trauma
extracranial infection eg nasopharynx, ear, sinuses
via bloodstream ie bacteraemic
what is the pathophysiology of meningitis?
bacteria enters CSF
can be isolated from immune cells due to BBB
replicates
BVs become leaky - WBCs enter CSF/meninges/brain
results in meningeal inflammation ± brain swelling
what are 3 classic symptoms of meningitis?
fever
headache
neck stiffness - “meningism”
(can’t tolerate bright light)
20% of bacterial meningitis patients can have permanent effects. list some
skin scars amputation hearing loss seizures brain damage
what does GCS (Glasgow coma score) help us determine
how sick pt - lower score = sicker
if they can maintain own airway
if there’s any raised ICP
what are 4 immediate management steps for someone who has bacterial meningitis?
- assess GCS
- blood cultures
- broad spectrum ABs (ceftriaxone, cefotaxime - both cross BBB)
- steroids (IV dexamethasone)
what is a definitive investigation to diagnose meningitis?
lumbar puncture
what are some contraindications to lumbar puncture?
abnormal clotting (platelets/coagulation) petechial rash raised ICP
what are some risk factors for bacterial meningitis
students
travel
(immunosuppressed)
what are some risk factors for viral meningitis
small children
immunosuppressed
if meningitis is in bloodstream, what do u get?
meningococcal septicaemia
non-blanching purpuric rash, necrosis, high mortality !
differential diagnosis for meningitis :
!subarachnoid haemorrhage! - trauma - “thunderclap” onset
also migraines, flu, brain abscess, malaria
what is encephalitis?
inflammation of the brain
what are causes of encephalitis?
p much always viral - herpes simplex (coldsore)
varicella zoster virus (chickenpox/shingles)
ask abt TRAVEL! eg rabies etc
what is the clinical present of encephalitis:
hrs to days: preceding ‘flu-like’ illness
then: altered GCS (confusion, drowsiness), fever, seizures, memory loss, ± meningism)
how do u manage encephalitis
MRI head ± EEG
lumbar puncture
DO A HIV TEST
treat: mostly supportive
recovery can be v long process
how does tetanus happen?
inoculation through skin w/ clostridium tetani spores found globally in soil
eg stepping on nail, dirty wounds
what happens in tetanus?
tetanospasmin (toxin that bacteria prod) - travels retrogradely along axons
interferes w neurotransmitter release - incr neutron firing - unopposed muscle contraction/spasm
how can tetanus be managed?
if at risk injury - vaccinate!
if symptomatic - support (muscle relaxants), IG, AB (metronidazole to clear any residual bacteria that may prod toxins)
how does rabies happen?
viral infection
inoculation through skin with saliva of rabid animal eg dogs/cats/foxes eg lick, bite, splash
travels retrogradely along nerves
how is rabies managed?
most ppl die
managed with sedatives
prophylaxis is key
what is dementia?
a set of symptoms - inc memory loss, problem solving language
gradual onset and progressive
Alzheimer’s is the commonest cause of dementia
what is Alzheimer’s disease a problem w?
storing of memories
what makes up the exclusion criteria for Alzheimer’s?
sudden onset
early occurrence of: gait, seizures, major behavioural changes
which med cond are severe enough that u can’t diagnose Alzheimers?
major depression
cerebrovascular disease
what is pseudodementia?
depressie dementia
what is the diff in depression/dementia on onset?
depression - trigger, onset/decline rapid
dementia - vague, insidious onset
what is the diff in depression/dementia on memory loss?
depression - aware, complaints of memory loss
dementia - unaware/attempt to hide problems
what is mood diff in depression vs dementia
depression - patient unhappy. “don’t know” answers
dementia - mood labile. attempts all questions
why Is temp lobe important?
hearing language comprehention semantics memory emotional/affecting behaviour
what happens in dementia with levy bodies (3)
fluctuation cognition
visual hallucinations
spontaneous Parkinsonism
why do u do a structural MRI in dementia patients?
to rule out other causes
see atrophy as a biomarker
what are the 2 main medications for dementia?
acetylcholine esterase inhibitors
memantine (anti-glutamate)
which diagnostic tests can be used for Alzheimer’s pathology
non-invasive (amyloid and tau PET ? imaging)
what are some key features of MS?
inflammatory, demyelinating tissue
specific to CNS
usually begins 20-40 yrs
progressive disability over time
which pops is MS more common in?
caucasian
prevalence can be altered by env change - age of migration is critical
what are the 2 types of lesions in MS?
active and inactive
what are common sites for plaque distribution in MS?
cerebral hemispheres
spinal cord
optic nerves
medulla/pons
what are some typical symptom in MS?
optic neuritis
spasticity
sensory symptoms/signs
bladder/sexual dysfunction
what are some atypical symptoms in MS?
aphasia
hemianopia
severe muscle wasting
what is the majority of MS patient’s course of illness?
in a relapsing/remitting fashion … full recovery from disease, stable until next attack etc etc cycles !
don’t need to recover fully each time
what are the 2 essential diagnostic criteria for MS?
2+ CNS lesions disseminated in time/space
exclusion of cond giving a similar clinical picture
what are some conditions misdiagnosed as MS?
SLE
lyme disease
syphilis
AIDS
what is the gold standard investigation for MS?
imaging !!!!!!!! MRI
blackouts can be bc of what?
problem w/ blood circulation (heart/BP)
disturbance of brain function (epilepsy)
what are the 2 types of seizures?
epileptic seizures and stress-related (non-epileptic) seizures
what are the 3 types of epilepsy - following epileptic seizures
idiopathic generalised epilepsy
unclassifiable epilepsy
focal epilsepsy
what is an epileptic seizure?
paroxysmal event in which changes of behaviour/sensation/cog processes are caused by excessive, hypersynchrous neuronal discharges in the brain
what is the usual duration of epileptic seizures
30-120s
what happens in an epileptic seizure?
“positive” ictal symptoms (seeing/hearing/feeling stuff that aren’t there)
may occur from sleep
may be associated with other brain dysfunction
typical seizure phenomena: lateral tongue bite, deja vu etc
what is syncope?
paroxysmal event in which changes in behaviour/sensation/cog processes are caused by an INSUFFICIENT BLOOD/OXYGEN SUPPLY to the brain
list some syncope characteristics
situational
sitting/standing
rarely from sleep
presyncopal symptoms (seeing stars, distorted noises, dizzy/light headed, blacked out vision)
duration 5-30 seconds
recovery within 30 seconds
what is cariogenic syncope like ?
less warning
history of heart disease
define non-epileptic seizure
paroxysmal event in which changes in behaviour/sensation/cog function caused by MENTAL PROCESSES ASSOCIATED W/ PSYCHOSOCIAL DISTRESS
what are some characteristics of non-epileptic seizures
situational
duration 1-20 mins
eyes closed
ictal crying/speaking
instead of panic attack ?
surprisingly rapid/slow postictal recovery
history of psych illness esp PTSD
what are some factors suggestive of epilepsy
tongue biting
head turning
muscle pain
what are some factors suggestive of syncope
prolonged upright position
sweating prior
nausea
presyncopal symptoms
what is focal epilepsy?
associated w/ focal brain abnormality, starts at any age
partial seizures w or w/o impairment of consciousness
1st line treatment: carbamazepine
what is idiopathic (primary) generalised epilepsy?
no associated brain abnormality, manifestation usually <30 years
absence seizures, myoclonic seizures or primary generalised tonic clonic seizures
1st line treatment:
valproate
how do anti-epileptics work?
taget GABA receptor/transporter or GABA transaminase
what do u do if anti-epileptics don’t work?
alternative mono therapy, combo therapy
consider epilepsy surgery - vagal nerve stimulator
what is essential in epilepsy diagnosis?
patient and witness history !
what’s the diff btwn new and conventional anti-eleptics
not much in terms of effectiveness but fewer side effects
define stroke
a clinical syndrome, caused by cerebral infarction/haemorrhage, typified by rapidly developing signs of focal/global disturbance of cerebral functions lasting more than 24h or leading to death