Neurology Flashcards
In AF what, apart from anticoagulation can you do to reduce the stroke risk?
Reduce blood pressure, aim SBP <133
Which investigation has the highest specificity for detecting AF?
Implantable loop recorder
Which of the NOAC’s carries a high risk of GI bleed?
Rivaroxaban and Dabigatran (150 but not 110).
How do the NOACS and warfarin compare for stroke risk reduction in AF?
All non inferior to warfarin for stroke and systemic embolism prevention
All NOACS significantly reduce hemorrhagic stroke
Are NOACS useful for primary and secondary stroke prevention?
Yes
Which renal function measure should you use when prescribing NOACs?
Cockroft-Gault Equation
In a systematic review for prevention of stroke in AF which NOAC had the highest expected incremental net benefit?
Apixaban 5mg BD
In patients post embolic stroke of unknown source (no confirmed AF) is rivoroxaban better than aspirin?
No primary outcome of stroke or other embolic event and major bleeding higher in the Rivoroxaban group compared to aspirin
What are some early findings on CTB non contrast in an ischaemic stroke?
1) Hyperdense artery (White section of artery)
2) Loss of grey/white matter differentiation due to hypodensity of great matter.
How does the ischaemic area appear on MRI brain DWI?
Ischaemic areas appear bright
What are the key metrics used to determine ischaemic core and penumbral size on CT perfusion scan?
1) Mean transit time
2) Tmax
3) Cerebral blood volume
4) Cerebral blood flow
Diagnostic Tests in seizure
EEG
MRI - on all patients apart from children with genetic epileptic disorder
Mesial temporal sclerosis on MRI
Flair + high signal in the temporal region
What is the treatment for absence seizures (PBS)
Ethosuxamide
Treatment for focal seizures (PBS)
Carbemazepine
What percentage of patients become seizure three on mono therapy AED
50% (90% on low to moderate doses)
Best anti-epileptic to use in women of child bearing age
Lamotrigine and leviteracetam (the L’s)
Drug resistant epilepsy
Seizures despite two, appropriate, anti-epileptic drugs
Diagnostic studies to consider in a patient who may be candidate for epilepsy surgery
MRI Spect (Interictal and Ictal) SISCOM FDG-PET Functional MRI (to identify eloquent cortext to avoid in surgery) Intracranial EEG
Novel therapies for drug resistant epilepsy
Vagus nerve stimulation
Deep brain stimulation (anterior nucleus of the thalamus)
Ketogenic Diet
Prevalence of epilepsy
1 in 26 = approx 4% of the population
When does childhood absence seizures typically onset?
During primary school age
Investigations in new onset seizure
Early EEG (within 24 hours) MRI (note 15% of findings missed on CT scan)
Treatment for benzo refractory status?
Leviteracetam = phenytoin = valproate
Best drug for generalised seizures? (PBS)
Valproate
+: Mood enhancer
-: Teratogenic (do not use in young women)
Best drug for mycolonus? (PBS)
Clonazepam
Lamotrigine uses and adverse effects
Generalised epilepsy
- Alternative to Valproate in young women and obese
Lennox Gastaut
A/E
Rash when used with valproate
Dizzy when used with carbamezpine
Leviteracetam uses and adverse effects
Focal epilepsy
- Alternative for pregnant women
Adverse effects
- Mood disturbances
Topiramate
Use
- Focal epilepsy add on therapy
Adverse effects
- CNS fog
- Renal stones as carbonic anhydrase inhibitor
- Weight loss
- Teratogenic ?
Perampenel
Uses
- Focal epilepsy add on
Adverse effects
- CNS effects: somnolence/dizziness/agression
- Slow titration
- Teratogenecity
MOA of vigabatrin?
Elevates brain GABA (prevents the breakdown)
Leviteracetam MOA
Binds to synaptic vesicular protein SV2A
Perampanel MOA
Blocks post synaptic AMPA (glutamate) receptors. Therefore down regulates excitatory action
Carbemazepime and SJS
HLA_B*1502
Predominant in Han Chinese or SE Asian descent
Therefore if treating these patients need to tests for HLA-B*1502
Carbemazepime and DRESS
HLA-A*31:01
Phenytoin related Dress/SJS
CYP2C9*3
Autoimmune limbic encephalitis
Anti LGl1: Anti potassium channel antibody (Older men)
Anti NMDA: Antibody to NMDA (young woman with teratoma)
EEG findings in liver failure
Triphasic waves
EEG finding in CJD
Biphasic synchronous waves approx 1 per second
Carbemazepime MOA
Blocks voltage gated and use dependent sodium channels.
Pyramidal weakness
Legs: Flexors weaker
Arms: extensors weaker
Gold standard of vertebral imaging
CT Angiogram
Hyper-acute stroke therapy
IV thrombolysis: 0-4.5 hours (within 9 hours from recent study)
Endo-vascular therapy: 12 hours (24 hours for posterior stroke with salvageable penumbra)
- Up to 12 hours NNT is 2.6!
Based on salvageable penumbra
TIA definition
Symptoms <1 hr with no evidence of damage on imaging
20% of patients with acute stroke will have TIA in the weeks to months prior to event.
Most risk within 7-10 days
8% mortality at 6 months
Indication for carotid enderartectomy
Symptomatic carotid stenosis
> 50-69% (moderate) recommended in men
> 70-99% (severe) recommenced within 14 weeks with an ARR of 30%
Criteria for CEA
- Ipsilateral stroke or TIA
- Life expectancy >5 years
- Accesible lesion
Note stenting: data worse only useful if poor surgical candidate i.e restenosis post CEA or radiation induced stenosis.
Peri-procedural death/stroke rate is higher
Hyper-acute stroke therapy
IV thrombolysis: 0-4.5 hours (within 9 hours from recent study)
Endo-vascular therapy: 12 hours (24 hours for posterior stroke with salvageable penumbra)
- Up to 12 hours NNT is 2.6!
Extending the time frames is based on salvageable penumbra
Indications for reduced dose of Apixaban to 2.5 BD
two of three
1) Age >80
2) Weight <60
3) Cr >133
DOAC with increased risk of bleeding?
Rivaroxaban
What to consider in a patient with stroke/AF with high bleeding risk
Consider left atrial appendage occlusion devices i.e watchman/amulet device
Prague 17 study
Head to head of Watchmann vs Apixaban
11% vs 13% of embolic stroke/complications
Other option would be surgical closure during cardiac surgery
When to consider PFO closure?
Patients = 60 yoa
Embolic stroke without other risk factors (esp AF)
Note risks of AF post procedure = 4-6%
