Neurology Flashcards
Why would you perform a lateral canthotomy?
What are 3 signs it is needed in unconscious and conscious patient?
Ocular compartment syndrome
Unconscious
RAPD
Raised intra ocular pressure
Dilated puptil suggesting retrobulbar haematoma
Conscious
Decreased acuity, pain, opthalmoplgeia
what are the poor prognosticating factors on SAH CT
- loss of white gray matter differentiaiton
- obstructive hydrocephalus
- tonsiller herniation
- loss of sulci
GBS v spinal cord lesion
what is the relevance of FVC and its interpreation in monitoring GBS?
what are the differentials for acute bilateral leg weakness?
- GBS
- lambert Eaton
- spinal cord compression/cauda equina
- hypokalaemia paralysis
- myasthenia gravis
- traumatic spinal cord injury
- spinal cord infarct
Classical triad of GBS
- symmetrical ascending weakness
- areflexia
- minimal sensory loss
what investigations are useful in ?GBS
- LP - raised protein and normal/low WCC
- anti ganglioside antibodies
- nerve conduction studes suggesting peripheral demyelination
what are the life threatening complications of GBS
- Resp - hypoventilation and respiratory arrest
- autonomic - labile BP and tachycardia
what are the clinical features of facial nerve palsy?
- weakness of upper and lower facial musculature
- decreased taste anterior 2/3 ipsalateral tongue
- ipsalateral hyperacuisis
- ipsalateal reduced tear production
what are the peripheral causes of an isolated facial nerve palsy??
meningioma/cholesteatoma
temporal bone fracture
parotid neoplasm
mastoid surgery
facial laceration
lyme
sarcoid
amyloid
GBS
diabetes
botulism
HIV
syphillis
what is the treatment for idiopathic bells palsy
What is the prognosis and what factors are associated with poorer income?
Treatment:
*eye care to prevent corneal exposure eg patch, lubricant
* pred 60mg 5/7 then taper
* ?need for antivirals
Prognosis
85% complete recovery 2 months
partial recovery
less chance of recovery in:
* pregnancy
* older age
* diabetes
* taste affected
what are the typical examination findings of third nerve palsy
- eye looks down and out (loss of adduction, elevation)
- ptosis
- mydriasis
in a third nerve palsy how does ipsalateral pupil dilation help distinguish aetiology?
Pupil constriction is mediated by parasympathetic fibres that accompany CN III they travel peripherally & are more susceptible to compression resulting in pupil dilation.
symptom not there in vascular cause
What are the causes of aniscoria?
- 3rd nerve palsy
- physiologica
- trauma
- horners
- acute close angle glaucoma
- drugs eg tropicamide
- Adies pupil
positive and negatives on scan
Diagnosis
positives
* hyperdensity in midbrain consistent with acute bleed
* dilatation of lateral horns consistent wth hydrocephalus
negatives
* no tonsiler herniation
* no midline shifft
* no intraventriclar blood
* no sign of trauma
Diagnosis
acute intracranial haemorrhage
what are the PRN end of life meds?
What are the components of OTTAWA SAH rule?
- age over 40
- neck stiffness
- witness LOC
- onset during extertion
- thunderclap
- limited neck flexion on examination
if any is a yes it cant be ruled out
what are the investigsations and pros and cons for ?sah 6 hours post presentation
What is the best scan within 6 hours?
**LP **
Pros - high sensitivy and specificty
cons - risks of infection, tine consuming, operator dependent
CTA
Pros - can diagnose aneurysms, pain free
Cons - 1-2% aneurysmic and may be asymptomatic
within 6 hours - CT
what are the ways to minimise post LP headache?
- atraumatic needle
- small needle calibre
- early mobilisation
- replace stylet before removal of needle
what can cause a headache and visual symptoms?
SAH
migraine
GCA
acute angle close glaucoma
CVA
SOL
what features of hx suggest migraine
prior migraines
FH
parasthesia
scotoma
nausea
photophobia
what is the first line medical treatment for migraine?
- paracetamol 1g PO
- ibuprofen 400mg PO
- Aspirin 900mg PO
- Sumitriptan 50mg PO
- Stemetil 12.5mg slow IV
what drugs can be used in migraine prophylaxis
propranolol
amitryptiline
verapamil
sodium valproate
what clinical features of GBS would suggest intubation is needed
FVC below 15ml/kg
bulbar weakness
tachynpnoea
hypoxia
what are the spinal tracts for movement and what do they control?
corticospinal - skeletal muscle
corticobulbar - cranial nerves
what part of the nervous system is responsible for involuntary movement
damage to what part causes involuntary movement
autonomic
damage to basal ganglia causes involuntary
Rinne
512 tuning fork on mastoid and infront of ear. Which is louder?
if louder on mastoid then conductive hearing is better
Wever
512hz tuning form in middle and say where louder
moves to conductive hearing loss or away from sensorineural
what are some atraumatic causes of senosorineural hearing loss?
post viral
gentamicin/vancomycin
vasculitis
sarcoid
what are the contraindications to LP
patient refusal
raised ICP
localised skin infection around site
focal neurological signs
coagulopathy
patient agitation
SAH symptoms
headache
vomiting
collapse
photophobia
neck stiffness
transient LOC
focal neuro signs
what are the break down products that make blood appear yellow
bilirubin
oxyhaemoglobin
What criteria would suggest a CT is needed before LP for ?SAH
signs if RICP
immunosuppression
focal deficit
new seizure
within 6 hours of ?sah headache
reduced GCS
three non tox causes
heat stroke
meningitis
hyperthyroid
name some tox causes and key examination findings
- serotonin toxicity - rigidity, hyperreflexia, mydriasis
- sympathomimetic - mydriases, tachycardia, hypertension
- anti-cholinergic - full bladder, tdry skin, flushed, delirium
4 drugs and doses for stopping seizure
- midazolam IV 5mg aliquots
- leviteracetam 40mg/kg IV
- phenytoin 20 mg/kg IV
- sodium valproate 1g
differentials for prolonged seizure
- head injury and ICH
- eclampsia
- primary epilepsy
- meningitis
- hypoglycaemia
5 serious complications of status
- hypoxic brain injury
- ICH
- pulmonary oedema
- rhabdo and AKI
- fractures eg spine
8 causes for first seizure
hypoglucaemia
primary epilepsy
meningitis
trauma and ICH
toxins - sympathomimetic
drug withdrawal
SOL
CVA
main side effects of IV phenytoin and management
- sodium channel blockade and widended qrs and VT - sodium bicarm 2mmol/kg IV every 2 mins
name some stroke mimics and how you may identify them
- hypoglycaemia - low bsl/known diabetic
- SOL - known CA
- seizure/todds paralysis - known epilepsy, witnssed seizure
- hemiplegic migraine - migraine sufferer, headache
- functional - psych hx
- MS - known hx
- Bells - LMN facial signs
what is the inclusion criteria for CVA thrombolysis
Clinical stroke +
* over 18
* clear onset within 4.5 hours
* No evidence of ICH on CT
* Consent
* focal deficit
exclusion criteria for CVA thrombolysis
- ICH
- no consent
- major surgery in last 14 days
- SBP over 185
- GI/GU bleed within 21 days
- platelets under 100
- on warfarin and INR over 1.5
- resolving neurology
what scoring system is used post TIA
ABCD2
finding
hyperdense MCA sign
What are the main causes of dizziness?
Peripheral - BPPV, vestibular neuritis, meinieres
Central - CVA, SOL, MS
other
hypoglycaemia
pre syncope
sepsis
list three history and three exam findings to help differentiate between central and peripheral causes of vertigo
Peripheral
* History - consitutinal sx, worse on movement, viral prodrome, tinnitus, hearing loss, sudden onset
* Exam - dix hallpike +ve, abnormal ENT exam, horizontal nystagmus
Central
* History - other neuro sx, CVS risk fx, gradual onset
* Exam - focal neuro deficity, other CN signs, vertical nystagmus, any cerebella sign
what investigations and why when looking at central v peripheral vertigo
What are the components of a HINTS exam and its clinical significance?
**1. nystagmus **- horizontal suggests peripheral. Vertical suggests central
2. head impulse test - correcrive saccade suggests periphral, none is central
3. Test of skew - abnormal skew test with ocular tilt suggests central
what features of nystagmus suggest central cause?
vertical or rotational
change in direction
non fatiguable
spontaneous
what are some differentials for hyperensive encephalopathy
ICH
menigoencephalitis
toxoplasmosis
SOL
migraine
hypoglycaemia
define:
hypertensive emergency
hypertensive urgency
hypertensive emergency - over180 or 120 with end organ damage or over 200
hypertensive urgency - over 180 or 120 with no end organ damage
drugs for hypertensive emergency
what is the target for treating hypertensive emergency/urgency
reduce MAP by 15-25% in 2 hours
what can cause apnoea post termination of seizure
over medication
hypercapnoea
hypoglycaemia
post ictal
coning eg SOL
subclinical seizure
SDH/EDH
menigitis
