Neuro Flashcards
Dermatome = ?
= area of skin supplied by a single spinal nerve/root
Myotome = ?
= volume of muscle supplied by a single spinal motor nerve
most muscles have more than one myotome
What does the lateral corticospinal tract control
rapid, skilled, voluntary movement
what does the anterior corticospinal tract control
rapid skilled voluntary movement
vestibulospinal tract role?
facilitates extensors, inhibits flexors (controls dizziness) and balance
rubrospinal tract role
facilitates flexors and and inhibits extensors
tectospinal tract role
truncal reflexes from sigths
Define TIA
= transient and reversible episode of sudden onset neurological dysfunction caused by ischaemia without acute infarction
symps usually resolve within 24 hours
Where do most TIAs occur
in the anterior circulation (carotid territory)
what are the most rapid acting antihypertensives used in acute BP lowering after stroke/haemorrhage
- IV labetamol (BB)
- IV GTN
define syncope attack
= paroxysmal event where changes in behaviour, sensation and cognitive processes are caused by insufficient blood/oxygen supply to the brain
3 causes of blackouts
syncope
epilepsy
non-epileptic seizures
precipitating factors for status epilepticus
alcohol abuse
abruptly stopping AEDs
intercurrent illness
poor compliance with tx
define myotonia
= delayed relaxation of muscle after contraction
characteristic pathology/general symptoms of MG
weakness and fatiguability of occular, bulbar and proximal limb muscles
4 conditions assoc w MG
RA
thyroid disease
pernicious anaemia
SLE
Ab involved in MG
anti-AChR and anti-MuSK
histology of MG
See AChR Ig and complement deposited at post synaptic membranes
occular symptoms of MG
diplopia, ptosis
What worsens the weakness experienced in MG
pregnancy hypokalaemia emotion infection exercise drugs
Mx of MG
PYRIDOSTIGMINE (= acetyl-cholinesterase inhibitor)
if not controlled, add steroids, gradually decrease prednis dose
if not controlled still, add MTX/azathioprine
thymectomy if difficult to control
plasmapharesis in severe exacerbation
what is the most common form of MND and what neurones are involved
Amyotrophic lateral sclerosis (ALS) - UMN & LMN
different patterns of onset in MND
limb onset (most common) bulbar onset (worse prognosis - 20%) resp onset (least common)
how would you distinguish MND from MS, MG and GBS
in MND:
- bladder and rectal sphincters usually spared
- no sensory symps
MND (ALS) general symps
eventually weakness and atrophy of all 4 extremities, trunk and bulbar muscles
characteristic sign in MND
fasciculations
what is Guillain barre syndrome (GBS)
= acute inflammatory demyelinating ascending polyneuropathy of PNS
what is GBS normally triggered by
an upper respt tract/GIT infection
common causative agents of GBS
CAMPYLOBACTER JEJUNI, CMV,
others: mycoplasma, zoster, EBV, HIV - 40% no infectious cause found
clinical presentation of GBS
1-3 wks post-inf: ascending symmetrical weakness, starting in distal muscles and progressing to more proximal ones over ~4wks
followed by recovery
see: loss of reflexes, neuropathic pain and autonomic dysfunction
signs of autonomic dysfunction
sweating, tachycardia, arrhythmias
what may lead to an ITU admission with GBS
involvement of resp muscles,
therefore must monitor FVC regularly in these pts
Mx of GBS
IV Ig
plasmapharesis (effective but rarely used)
MONITOR VENTILATION
3 cardinal symptoms/signs of brain tumour
symps of raised ICP
progressive neurological deficit
epilepsy
signs of raised ICP
headache, drowsiness, N&V
cardinal physical sign of brain tumour
papilloedema
cell origin of most primary brain tumours
glial cell (mainly astrocytomas)
what is dexamethasomes action
decreases cerebral oedema
Mx of GBM
TEMOZOLOMIDE = chemo has radically improved survival in pts with MGMT mutant
other mx: surgical resection (w. post-op chemo), RT,
mx of secondary brain tumours
surgery not often poss but surgery and chemo have best outcome
BSC often as effective as RT and prolongs QOL
causes of meningitis in neonates
E coli, group B B-haemolytic strep
causes of meningitis in adults
n. meningitidis, strep. pneumoniae, (h. influenzae)
causes of meningitis in eldery
n. meningitidis, strep. pneumoniae, listeria
causes of meningitis in immunocompromised
CMV, cryptococcus (stains with INDIA INK), TB
S&S of meningitis
headache meningism = neck stiffness and photophobia Kernig's and Brudinski sign Non-blanching petechial rash altered mental state (oedema) fever seizures
Mx of meningitis
if suspect bacterial - start ABX immediately
IV cefotaxime (if community benzylpenicillin)
if >50 add ampicillin to cover for listeria
dexamethasome - decrease cerebral oedema
Notify PHE!!
prophylaxis of meningitis
rifampicin/ciprofloxacin
what is encephalitis
inflam of brain parenchyma
affects frontal and temporal lobes –> decreased consciousness, confusion and focal signs
what causes encephalitis
viral infection - most commonly HSV1 and 2
others: varicella zoster, EBV, mumps, measles, CMV, HIV
non-viral - secondary to bacterial meningitis, TB, toxoplasma
S&S of encephalitis
features of viral inf
DECREASED CONSCIOUSNESS
behavioural change, focal neurological deficit, coma, seizures
mx of encephalitis
if viral URGENT ACYCLOVIR
if meningitis suspected, emergency IM benzylpenicillin
